1[Type text] Peri-implant tissue condition evaluation following flap and flapless dental implant placementClinical and radiographic evaluationA ThesisSubmitted to faculty of Dental MedicineAl-Azhar University, Cairo, in Partial Fulfillment ofThe Requirement of the Master DegreeInOral Medicine, Periodontology,Oral Diagnosis and Radiology.By Mohamed Ismael As- Sa'daway Alwakel(B.D.S) (2003G)Faculty of Dental Medicine for boys AlazharUniversityCairo Demonstrator of Oral Medicine, Periodontology, Oral Diagnosis and Radiology Faculty of Dental MedicineAlazharUniversityCairo (Boys) Egypt2013G-1434HSupervisorsDr. Akram Abass ElawadyProfessor of Oral Medicine, Periodontology, Diagnosis and Radiology,Faculty of Dental Medicine, Al-Azhar University,Cairo (Boys)Dr. Magdy Kamel MohamedAssociate Professor of Oral Medicine, Periodontology, Diagnosis and Radiology,Faculty of Dental Medicine, Al-Azhar UniversityCairo (Boys).Dr. Fatma Mohamed RayanLecturer of Diagnosis and Radiology,Faculty of Dental Medicine, Al-Azhar University,Cairo (Girls).Dr. Radi Massoud KumperLecturer of Oral Medicine, Periodontology, Diagnosis and Radiology,Faculty of Dental Medicine, Al-Azhar UniversityCairo (Boys).List of contentsNo of content pages1-Introduction 13 2-Review of Literature 153-Aim of the Study 424-Patients and Methods 455-Results 626-discussion 1027-Summary and Conclusions 1118-References 1169-arabic summary 140 LIST OF TABLESTable no.TitlePage1The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between PPD of the two techniques622The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean PPD of each technique693The mean %, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between percentages of change in PPD 704The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between GI of the two techniques715The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean GI of each technique736The mean %, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between percentages of change in GI 747The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between pain VAS scores of the two techniques758The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between comfort VAS scores of the two techniques769The mean, standard deviation (SD) values and results of paired t-test for comparison between bone height measurements of the two techniques7710The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean bone height measurements using flapless technique7911The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean bone height measurements using flap technique8012The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between amounts of bone loss8113The mean, standard deviation (SD) values and results of paired t-test for comparison between mean gray value measurements of the two techniques8314 The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean gray value measurements using flapless technique8415The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean gray value measurements using flap technique8416The mean %, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between percentages of change in mean gray value.8617The mean, standard deviation (SD) values and results of paired t-test for comparison between integrated bone density measurements of the two techniques8818The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean integrated bone density measurements using flapless technique8919The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean integrated bone density measurements using flap technique.9020The mean %, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between percentages of change in integrated bone density 9221The mean, standard deviation (SD) values and results of paired t-test for comparison between raw integrated bone density measurements of the two techniques9422The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean raw integrated bone density measurements using flapless technique9523The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean raw integrated bone density measurements using flap technique9624The mean %, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between percentages of change in raw integrated bone density 98 Aim of the study LIST OF FIGURESFigure no.TitlePage1Bone sounding procedure (ridge mapping).452A study model was sectioned and the soft tissue was delineated453Metal sphere implanted within acrylic resin base464Digital panoramic image with a metal ball determining implant position and showing equal magnification.475A radiographic transparent template486The transparent template overlapped on the panoramic image487Evaluation of the panoramic image of the selected implant site relation to mandibular canal with the measurement of the distance from bone level to the canal to be sure that the height selected is away and suitable.498A: Crestal horizontal incision was made and the flap was elevated. B: Mucosal punching for the standard (narrow/wide) diameter of implant.509A: Periimplant probing depth for flap right side. B: Periimplant probing depth for flapless left side.5110Visual Analogue Scale (VAS)5211Planmeca Prolin XC unit.5212Acrylic bite block for patient to bite each time at the same position during exposure5313Periapical image of implant5414Diagrammatic representation of reference lines for level height measurement.5515Inverted image showing area of densitometric analysis mesial to the implant (blue line).5616Bar chart representing comparison between PPD of the two techniques6817Line chart representing changes by time in PPD of each technique6918Bar chart representing mean % change in PPD of the two techniques7019Bar chart representing comparison between GI of the two techniques7220Line chart representing changes by time in GI of each technique7321Bar chart representing mean % change in GI of the two techniques7422Bar chart representing comparison between pain VAS scores of the two techniques7523Bar chart representing comparison between comfort VAS scores of the two techniques7624Bar chart representing comparison between bone height measurements of the two techniques7825Line chart representing changes by time in bone height measurements of flapless technique7926Line chart representing changes by time in bone height measurements of flap technique8027Bar chart representing mean amounts of bone loss with the two techniques8228Bar chart representing comparison between mean gray value measurements of the two techniques8329 Line chart representing changes by time in mean gray value measurements of flapless technique8530Line chart representing changes by time in mean gray value measurements of flap technique8531Bar chart representing mean % change in mean gray value of the two techniques8732Bar chart representing comparison between integrated bone density measurements of the two techniques8833Line chart representing changes by time in integrated bone density measurements of flapless technique9034Line chart representing changes by time in integrated bone density measurements of flap technique9135Bar chart representing mean % change in integrated bone density of the two techniques9336Bar chart representing comparison between raw integrated bone density measurements of the two techniques9437Line chart representing changes by time in raw integrated bone density measurements of flapless technique9638Line chart representing changes by time raw integrated in bone density measurements of flap technique9739Bar chart representing mean % change in raw integrated bone density of the two techniques9940Subtracted images and color subtraction showing difference in bone around implants. A: for flap site & B; the same in color subtraction. C: for flapless site & D: the same in color subtraction. Where color subtraction accentuates the area around implant with extent of osteointgration, (red color intensity decreases with increase bone deposition).10041Digital panoramic subtracted image showing the difference between flapless (left) and flap (right).101List of abbreviationsTerms description1CBL Crestal Bone Loss2PI Papillary Index3PPD Periimplant Probing Depth 4PICF Periimplant Crevicular Fluid5TGF Transforming factor6PRGF plasma Rich in Growth Factor7BMP Bone Morphogenetic Proteins8TPS Titanium Plasma Sprayed9RFA Resonance Frequency Analysis1oISQ Implant Stability Quotient11DSI Digital Subtraction Image12MRI magnetic resonance image Dedication To my mother, I bow down for all her blessings, love and unquestioning support and encouragement throughout my study. To my wife and my daughter Fatimah, special thanks Acknowledgement There are moments when, whatever may be the attitude of the body, the soul is always praying. Glory to Allah Who art perfect in knowledge and wisdom. I owe an enormous debt of gratitude and deep sincere thanks to Prof Dr. Akram Abass Elawady Professorof Oral Medicine, Periodontology, Diagnosis and Radiology, Faculty of Dental Medicine, Al-Azhar University, Cairo (Boys) For sharing his vast experiences, most valuable guidance, continuous encouragement and timely suggestions not only in taking up this study but throughout my postgraduate course.. I wish to give my best thanks to Dr. Magedy kamel Mohamed Associate Professor of Oral Medicine, Periodontology, Diagnosis and Radiology, Who continually conveyed a great help in regard to a research and scholarship. I am greatly indebted to Dr. Fatma Mohamed Rayan, Lecturer of Oral Diagnosis and Radiology, Faculty of Dental Medicine, Al-Azhar University, Cairo (girls). For patiently guiding me not only for this study but also throughout my post graduate course. I will always be thankful to her. I would like to express my sincere gratitude and deepest appreciations to my supervisor Dr. Radi Massoud kumper Lecturer of Oral Medicine, Periodontology, Diagnosis and Radiology, Faculty of Dental Medicine, Al-Azhar University, Cairo (Boys) for his scientific advice, great co-operation, and support, I will remain grateful to him.Finally, I wish to express my best thanks to my family, friends and colleagues, who have supported me. Introduction The introduction of osseointegration in 1977 by Brnemark (1) revolutionized oral rehabilitation in partially and fully edentulous patients. This concept was based on the utilization of a mucoperiosteal flap. The flap was designed for the visualization of underlying bone by reflecting the alveolar crest soft tissue for placement and closure with suture on completion of the procedure. This concept implies that implants should be covered by soft tissue to warrant primary stabilization and decrease infection as a standard of care. It has the advantage of allowing better visualization, particularly in areas of inadequate bone quantity and it permits the manipulation of soft tissue. Despite their popularity, flap techniques have disadvantages including gingival recession, bone resorption around natural teeth. (2, 3) There have been many modifications to implant flap design, including the flapless surgical technique. Flapless surgery was first introduced by kan in 2000.(4) In contrast to the flap technique, implant flapless surgery does not require reflection of a mucoperiosteal flap while perforating the alveolar mucosa and bone. Therefore, flapless surgery generates less postoperative bleeding, less discomfort for the patient, surgery time is shorter, and healing time is reduced.(5) The flapless technique uses rotary burs or a tissue punch to gain access to bone without flap elevation, so the vascular supply and surrounding soft tissue are well preserved.(6) Flapless surgery has been regarded as having multiple limitations such as: poor control of precise drilling depth due to difficulty in observing the drilling direction of the alveolar bone; inability to preserve keratinized gingiva with a tissue punch perforation; and poor ability to assess the implant point of entry due to the lack of direct vision of the recipient bone. For many practitioners, the flap technique has remained the mainstay of implant surgery However, with the advances of flapless surgery; the traditional flap method is being challenged because it is being perceived as unnecessary for some practitioners. Review of literature Surgical and restorative concepts related to implant dentistry have been modified tremendously through the years. The ultimate goal of implant-supported restorative therapy is to replace a tooth with a structure that will mimic what is lost functionally and esthetically. Several surgical techniques have been developed to regenerate soft and hard tissue. These procedures allow the dentist to increase tissue support around dental implants. In addition, several parameters have been developed to control the esthetic outcome of the treatment. The initial trend of case reports and personal communications has been replaced by clinical studies, though there is still a need for well-controlled, longitudinal investigations. General dentists and specialists who would like to include implant dentistry in their practices should be familiar with the current improvements and limitations of this fast-developing discipline. (7) Flap surgical techniques for implant placement The original Branemark (1)flap design protocol required a vestibular flap with a two stage approach. The implant was placed and buried under a full-thickness flap and an adequate period of healing (about three months mandible, six months maxilla). The original protocol suggested that covering the implants eliminate bacterial contamination and avoid micro movements during osseointegration. A second stage surgery then was performed with crestal incisions to expose the fixtures and connect a trans-epithelial abutment. After adequate soft tissue healing, the restorative dentist could fabricate the prosthesis. (8) One stage surgical protocols were developed by ITI in Switzerland that allowed the implant fixture to extend through the soft tissues during the period of initial healing. (9) This protocol was shown to be effective using a two stage system with the same predictability. (10) Several flap and suturing techniques have been proposed. Soft tissues are often manipulated and augmented for aesthetic reasons. It is often recommended that firm (attached/keratinized) soft tissues rather than movable mucosa to improve their long-term prognosis surround implants (11) There is insufficient evidence to recommend a specific flap or suturing technique. (12) When dental implants are placed by raising a surgical muco periosteal flap, there is an associated slight cresal bone loss (CBL) (13) at the site, Scarring and other complications are of concern. (14) Flapless surgical technique for implant placement In recent years some interest has arisen in how to develop techniques, such as flapless surgery, that can provide functionality, aesthetics and comfort with a minimally invasive surgical approach for implant insertion (15) Flapless implant surgery was reported to be associated with high success rates and can result in reduced intra operative bleeding and decreased postoperative pain and discomfort. (16) also reduced postoperative swelling, and the risk of hematomas. (17) (18) The aim of minimally invasive flapless surgery is to reduce periosteum delamination and preserve the soft tissue architecture (5) including the gingival margins of the adjacent teeth and the interdental papillae (19). The flapless approach also shortens the length of the surgery, accelerates recovery, (6), (20) and prevents complications arising from soft-tissue elevation such as infection, dehiscence and necrosis, and provides dental implant success rates equal to conventional flap technique (18). Flapless implant surgery provides preservation of the vessels, (5) (18) (21) (22) maintenance of the original mucosal form around the implants, (23) ((24) and retention of hard tissue volume at the surgical site. (25) The single-phase flapless surgery, a less complex protocol and the reduced operation time is psychologically and financially acceptable to patients. (26) Avoiding separation of the periosteum from the underlying tissue may result in a better-maintained blood supply to the marginal bone, thus reducing the likelihood of bone resorption (27) and enhance implant stability compared to the conventional ap surgery protocol. (28) With avoidance of vertical incisions close to the implant site, a smoother healing and better overall result were obtained. (29) (30) Flapless dental implant placement is possible in selected Patients but limited to those sites with adequate or augmentable attached gingiva and available bone volume and density. (29), (31) However, the true quality and quantity of bone underlying the mucogingival covering cannot be directly observed. (32) (33) The lack of direct visualization requires greater surgical skill, surgical guides (34) and experienced clinicians. (29), (31) The topography of the underlying available bone is key information in the decision for a flapless procedure. An appropriate site requires 5 mm of facial- lingual width and 7 mm of mesiodistal length. These dimensions allow a standard-sized diameter (3.54.2 mm) root form screw type or press fit implant to be placed with adequate bone housing and implant-dental spacing. The vertical platform position should be 2 to 4 mm apical to the adjacent proximal cemento-enamel junction. (35) In the case of an unsatisfactory anatomy of the alveolar ridge, methods of alveolar ridge augmentation might need to be employed. (36) Very small diameter (1.8 mm, mini) implants may be placed flaplessly but a denser quality of bone may be necessary for implant stability as well as an adequate zone of attached gingival for protection of the implant epithelial coronal attachment. (20) Flapless surgical procedures As the one stage implant surgery became more predictable, there was an interest in pushing the surgical part another step and placing the implant with a flapless approach. Flapless surgery procedures can be divided into 3 categories; Traditional Approach, Model Based Approach and Computer Assisted Approach. Traditional Based approach require Traditional Approach require a reasonable understanding of the bone and soft tissue profile of the area and includes use of an initial tissue punch and sequential drilling to widen the osteotomy and implant placement and a surgical guide might be required. (37) Model Based Approach involves the use of study models with ridge mapping information transferred to the model. Ridge mapping involves the use of a calibrated probe with a stopper to measure the thickness of the tissue along the edentulous site on a bucco-lingual manner including the crest. The information of each reading in the location is then transferred to the model in the form of dots on the model corresponding to the same location. The model is then sectioned and the ridge form can be evaluated. Based on this information, a surgical guide can then be fabricated. (38) Computer Based Approach, a new method that allowed placing multiple implants in a flapless approach with greater predictability and precision. This method involves the use of a radiographic guide and a 3D scan of the patient with the radiographic guide in order to generate a 3D model of the edentulous site in the computer. At this point, with the help of an implant planning software, a virtual implant is placed with the anticipated future restoration, in terms of angulations, length, width and location of the implant. (39) The information is then sent to the company, which will make a stereo lithographic surgical guide milled from the information obtained from the planning software. (40) A guide generated in this manner allows the implant surgeon to place the implant within a 5 degree error. Since the planning allows for implants to be placed with such little error it is even possible to plan on the final abutment and the prosthesis at the same time. (41) (42) When a flapless surgical procedure is planned, a tissue punch is used to remove the mucosa on the crest of the ridge and an osteotomy is performed. Implants are inserted without raising the periosteal flap, by employing either immediate implantation after tooth extraction or punch incision; with a cylindrical punch hole is made using trephine or transmucosal implantation; implants are inserted directly through muco periosteum. (26) Tissue response around dental implant Implants with poor secondary stability relates to the degree of osseointegration that occurs during bone formation and Soft tissue response. Pathological changes in the peri-implant tissues may be placed in the general category of peri-implant disease. (43), (44) Inflammatory changes, which are confined to the soft tissue surrounding an implant, are diagnosed as peri-implant mucositis (45), (46). Progressive peri-implant bone loss in conjunction with a soft tissue inflammatory lesion is termed peri-implantitis (45) (46) Peri-implantitis begins at the coronal portion of the implant, while the more apical portion of the implant maintains an osseointegrated status. This means that the implant is not clinically mobile until the late stages, when bone loss has progressed to involve the complete implant surface. (43) The implant gingival tissues serve as barrier function and necessitate the integration of three types of tissues: bone, soft connective tissue, and epithelium. The morphology of the healthy soft tissue adjacent to teeth has many features in common with that adjacent to implants: Both types of tissue have a well-keratinized oral epithelium, a junctional epithelium and a connective tissue lateral to the junctional epithelium and between the bone crest and the most apical extension of the junctional epithelium. (47) The vascular topography of the soft tissues around implants demonstrates that the soft tissue blood supply is derived from terminal branches of larger vessels from the bone periosteum at the implant site and blood vessels adjacent to juntional epithelium. (48) The cause of peri-implant tissue breakdown is multifactorial, but bacterial infection and biomechanical overload are considering major factors. With Bacterial infection, plaque accumulates on the implant surface, the sub epithelial connective tissue becomes infiltrated with inflammatory cells. (45) When the plaque continues to migrate apically, clinical and radiographic signs of tissue destruction are seen around implants. (49) (50) Sub gingival bacterial flora associated with clinically inflamed implant sites are very similar to those occurring around natural teeth and bacterial flora in adult periodontitis and peri-implantitis seem to have great similarities. (51) Excessive biomechanical forces lead to high stress or micro fractures in the coronal bone-to-implant contact and so lead to loss of osseointegration around the neck of the implant (52) (53) The role of loading is likely to have increased influence in clinical situations with poor bone quality, insufficient transmission, heavy occlusal function associated with parafunctions, and misfit of the prosthesis. Crestal bone resorbs around a titanium screw implant 0.9 to 1.6 mm during the first year of function. In the follow-up period, average annual rates of bone loss decrease to 0.05 to 0.13 mm . (54) Increased bone loss around titanium implants after a period of implant function is seen in 4 to 15% of the implants, with probing depths exceeding 5 mm in 5 to 20% of the implants. (55) Implant surface characteristics like hydroxyapatite-coated implants show higher amounts of peri-implant marginal bone loss (43) Primary implant stability depends on the surgical technique, implant design and implantation site. Cortical bone allows a higher mechanical anchorage to the implant than cancellous bone. Primary stability limits micro-motion of the implant in the early phases of tissue healing and favors successful osseointegration. (56) Dental implant manufacturers have suggested protocols to clinicians for earlier restoration and immediate, early, and delayed loading of dental implants. Many dental implant manufacturers are recommending single-stage surgical approaches, as well as immediate placement into extraction sockets. The method of placing and uncovering the implant may likely affect how the soft tissues react over time. (57) Bone healing around implants involves a cascade of cellular and extracellular biological events that take place at the bone-implant interface until the implant surface appears finally covered with a newly formed bone. These biological events include the activation of osteogenetic processes similar to those of the bone healing process, at least in terms of initial host response, this cascade of biological events is regulated by growth and differentiation factors released by the activated blood cells at the bone-implant interface. The host response after implantation is modified by the presence of the implant and its characteristics, the stability of the fixation and the intraoperative heating injuries that include death of osteocytes extending 100-500 m into the host bone. (58) Major stages of skeletal response to implantation-related injury and key histological events as related to the host response include hematoma formation and mesenchyme tissue development, woven bone formation through the intramembranous pathway, and lamellar bone formation on the spicules of woven bone. The first biological component to come into contact with an endosseous implant is blood Blood cells including red cells, platelets, and inflammatory cells such as polymorph nuclear granulocytes and monocytes emigrate from post-capillary venules, and migrate into the tissue surrounding the implant. The blood cells entrapped at the implant interface are activated and release cytokines and other soluble, growth and differentiation factors. (59) Initial interactions of blood cells with the implant influence clot formation. Platelets undergo morphological and biochemical changes as a response to the foreign surface including adhesion, spreading, aggregation, and intracellular biochemical changes such as induction of phosphotyrosine, intracellular calcium increase, and hydrolysis of phospholipids. The formed fibrin matrix acts as a scaffold (osteoconduction) for the migration of osteogenic cells and eventual differentiation (osteoinduction) of these cells in the healing compartment. Osteogenic cells form osteoid tissue and new trabecular bone that eventually remodels into lamellar bone in direct contact with most of the implant surface (osseointegration). (60) Osteoblasts and mesenchymal cells seem to migrate and attach to the implant surface from day one after implantation, depositing bone-related proteins and creating a non-collagenous matrix layer on the implant surface that regulates cell adhesion and binding of minerals. This matrix is an early-formed calcified afibrillar layer on the implant surface, involving poorly mineralized osteoid similar to the bone cement lines and laminae limitans that forms a continuous,0.5 mm thick layer that is rich in calcium, phosphorus, osteopontin and bone sialoprotein. (61) Peri-implant osteogenesis can be in distance and in contact from the host bone. Distance osteogenesis refers to the newly formed peri-implant bone trabeculae that develop from the host bone cavity towards the implant surface. In contrast, contact osteogenesis refers to the newly formed peri-implant bone that develops from the implant to the healing bone. The newly formed network of bone trabeculae ensures the biological fixation of the implant and surrounds marrow spaces containing many mesenchymal cells and wide blood vessels. A thin layer of calcified and osteoid tissue is deposited by osteoblasts directly on the implant surface. Blood vessels and mesenchymal cells fill the spaces where no calcified tissue is present.(62). The newly formed bone was laid down on the reabsorbed surface of the old bone after osteoclastic activity. This suggested that the implant surface is positively recognizable from the osteogenic cells as a biomimetic scaffold, which may favor early peri-implant osteogenesis. Cement lines of poorly mineralized osteoid demarcated the area where bone reabsorption was completed and bone formation initiated. A few days after implantation, even osteoblasts in direct contact with the implant surface began to deposit collagen matrix directly on the early formed cement line/lamina limitans layer on the implant surface. Osteoblasts cannot always migrate so rapidly to avoid being completely enveloped by the mineralizing front of calcifying matrix; these osteoblasts became clustered as osteocytes in bone lacunae. (61) The early deposition of new calcified matrix on the implant surface is followed by the arrangement of the woven bone and bone trabeculae. This is appropriate for the peri-implant bone healing process as it shows a very active wide surface area, contiguous with marrow spaces rich in vascular and mesenchymal cells. Marrow tissue containing a rich vasculature supports mononuclear precursors of osteoclasts so bone trabeculae remodel faster than cortical bone. (62) Initially, rapid woven bone formation occurs on implants to restore continuity, even though its mechanical competence is lower compared to lamellar bone based on the random orientation of its collagen fibers. Woven and trabecular bone fill the initial gap at the implant-bone interface. Arranged in a three-dimensional regular network, it offers a high resistance to early implant loading. Its physical architecture including arches and bridges offers a biological scaffold for cell attachment and bone deposition that is biological fixation. (63) The early peri-implant trabecular bone formation ensures tissue anchorage that corresponds to biological fixation of the implant. This begins at 10 to 14 days after surgery. Biological fixation differs from primary (mechanical) stability that is easily obtained during the implant insertion. Biological fixation of the implant involves biophysical conditions such as primary stability that is implant mechanical fixation, bio-mimetic implant surface and right distance between the implant and the host bone. It is prevalently observed in rough implant surfaces. (62) Woven bone is progressively remodeled and substituted by lamellar bone that may reach a high degree of mineralization. At three months post-implantation, a mixed bone texture of woven and lamellar matrix can be found around different types of titanium implants. (58) Peri-implant bone contains regular osteons and host bone chips enveloped in mature bone. The implant surface is covered with flattened cell. The bone-implant interface shows inter-trabecular marrow spaces delimited by titanium surface from one side and by newly formed bone from the other one rich in cells and blood vessels. (62) Host bone chips between the implant and the host bone cavity presumably occur from the surgical bur preparation or implant insertion. These are enveloped in a newly formed peri-implant trabecular bone, and seem to be involved in trabecular bone formation during the first weeks, i.e., in the biological fixation of the implant, by improving and guiding peri-implant osteogenesis as osteoconductive and osteoinductive biological material. Therefore, it was stressed that it is useful in clinical practice to avoid irrigation with a saline solution or aspirating the bone cavity before or during the implant insertion. (64) Factors that affect peri-implant osteogenesis include might the decreased number and/or activity of osteogenic cells, the increased osteoclastic activity, the imbalance between anabolic and catabolic local factors acting on bone formation and remodeling, the abnormal bone cell proliferation rate and response to systemic and local stimuli and mechanical stress, and the impaired vascularization of the peri-implant tissue. Vascularization is of critical importance for the process of osseointegration. Differentiation of osteogenic cells strictly depends on tissue vascularity. Ossification is also closely related to the revascularization of the differentiating tissue. Since aging impairs angiogenesis, biomaterial osseointegration is also reduced. In the elderly ,the association of impaired angiogenesis with osteoporosis increases the implant failure risk. (65) Bone in contact with the implant surface undergoes morphological remodeling as adaptation to stress and mechanical loading. The turnover of peri-implant mature bone in osseointegrated implants is confirmed by the presence of medullary or marrow spaces containing osteoclasts, osteoblasts, mesenchymal cells and lymphatic/blood vessels next to the implant surface. During the remodeling of the peri-implant bone, new osteons circle around the implant with their long axes parallel to the implant surface and perpendicular to the long axis of the implants. Osteoid tissue is produced by osteoblasts suggesting that osteogenesis is underway. The remodeled bone can extend up to 1 mm from the implant surface. (62) An understanding of normal bone formation and remodeling, through which such architectures are achieved, may well provide an insight into both the healing of bone around implants and the influence of implant surface design on such healing mechanisms .Bone tissue is arranged in two macro architectural formstrabecular (or cancellous, or spongy) and cortical (or compact)which are employed in various proportions and geometries to form the individual bones of the body. This constant remodeling of bone tissue provides a mechanism for scar-free healing and regeneration of damaged bone tissue, and results in the exquisite lamellar micro architecture of both cortical and trabecular mature bone. (66), (67) Contact osteogenesis relies upon osteoconduction, or the recruitment and migration of differentiating osteogenic cells to the implant surface, together with de novo bone formation by those cells on the implant surface. Osteoconduction also occurs during normal tunneling remodeling in bone. In such remodeling, differentiating osteogenic cells are derived from undifferentiated peri-vascular connective tissue cells (pericytes). (68) Platelets can be expected to be of particular importance in these early stages of healing since their activation results in the release of cytokines and growth factors that are known to accelerate wound healing. Although the exact mechanisms have yet to be elucidated, a small number of reports have emerged that show that the presence of an implant material may have profound effects on early blood cell reactions, including the agglomeration of red blood cells. (69) The initial adhesion of platelets has been shown to be mediated by GPIIb/IIIa integrin binding to implant surface adsorbed fibrinogen Thus, surfaces of greater micro topography will exhibit an increased surface area and a resultant increase in fibrinogen absorption, which could explain the observed increase in platelet adhesion. (70) it has shown not only that platelet activation is a function of substrate surface topography, (71) But also that platelets activated on micro textured candidate implant surfaces will up regulate neutrophils the first leukocyte population to enter the wound site during the acute inflammatory phase of healing. (69) Implant surface modifications influence tissue growth Several approaches have been devised to improve tissue in growth to synthetic implants. Surface modification is the most prevalent approach by changing surface topography or adsorbing bioactive factors. Certain topographic features fabricated on implant surface are generally associated with enhanced cell adhesion, such as osteoblasts adhesion to implant surface.(71) It has been shown that finely pitted (micropits of 1 to 3 m and larger elements of approximately 6 to 10 m) surfaces result in early enhancement of bone-implant integration.(72) The modified surface provides a configuration that properly retains the blood clot and stimulates the bone healing process, which allows implants with modified surfaces to be loaded earlier. Bioactive cues are typically adsorbed to biomaterials, such as hydroxyapatite or hydro gel polymers, that are coated on the implants surface. The transforming growth factor (TGF) super family has been the most commonly used bioactive cues, including TGF-s and bone morphogenetic proteins (BMPs).(73) TGF-1 plays a major role in the modulation of the behavior of multiple cell lineages, such as fibroblasts and osteoblasts, which are of relevance to wound healing and tissue regeneration.(74, 75)TGF-1 also up-regulates molecules that are critical to tissue integration on implant surface and bone ingrowth, such as alkaline phosphates, type I collagen, bone sialoprotein, and osteocalcin .TGF-1 is further efficacious in increasing the calcium content and the size of calcified nodules of primary osteoblasts.(76)Autologous plasma rich in growth factors (PRGF) has been shown to enhance and accelerate soft tissue repair and bone regeneration in the preparation of future sites for dental implants.(77) A preparation of PRGF applied to a titanium implant adheres to the metal and might create a new dynamic surface that could potentially show biological activity Osseointegration was enhanced by covering the implant surface with PRGF before insertion into the alveolus. The clinical use of this biologically active surface in oral implant logy might improve the prognosis.(78)to accelerate the osseointegration of the implants in patients with osteoporosis, one of the most current methods is the use of PRGF (plasma rich in growth factors) .(79) PRGF contains, in addition to growth factors, adhesive proteins: fibrin, fibronectin, vitronectin, von Willebrand factor, thrombospondin, laminin. Application of PRGF on the titanium implant surface can create a dynamic area with potential biological activity that ensures interaction of the implant surface with the surrounding tissues.(78) It is generally accepted that calcium phosphate materials, whether they are employed as lithomorphs or coatings, provide two advantages over most other endosseous materials. First, they accelerate early healing. Second, they bond to bone.(80) Calcium phosphate is readily adsorbing proteins to their surfaces. Potentiating protein adsorption on calcium phosphate surfaces (with respect to uncoated metal oxide surfaces) could be expected to increase the binding of fibrinogen that would lead to increased platelet adhesion and, possibly, result in increased platelet activation that would accelerate healing. Increasing protein adsorption could also include an increase of, or improvement in, fibrin binding to the implant surface resulting in an earlier establishment of the three-dimensional matrix through which osteogenic cells have to migrate to reach the implant surface. Thus, calcium phosphate coatings could have a biphasic effect on both platelet activation and fibrin binding. (81) It has been found that platelet activation on calcium phosphate surfaces is a function of the surface topography of the calcium phosphate, rather than due to the presence of calcium and phosphate ions in the surface of the material .it is almost impossible to vary substrate surface chemistry without altering the substrate topography. (82) The mechanism for the bone-bonding phenomenon is generally accepted to be a chemical interaction that results in collagen, from the bony compartment interdigitation with the chemically active surface of the implant. Clearly, in the case of de novo bone formation and contact osteogenesis, this mechanism is inconceivable since the first extracellular matrix elaborated by bone cells at the implant surface is collagen-free. As cement lines are found on both nonbonding and bonding biomaterials, then are evaluation of the phenomenon of bone bonding is essential. experimental evidence demonstrates than in cases of de novo bone formation at implant surface, bonding is achieved by micro-mechanical interdigitation of the cement line with the material surface.(83)Implant surface micro topography is critical to not only the generation of contact osteogenesis, but also whether the elaborated bone matrix will bond to that surface.(81) The porous implants showed a 96 percent increase in bone-to implant contact and a 50 percent increase in the growth of new bone over placebos. Because stem cells play a vital role in the growth of new bone, Dr. Mao and colleagues (84)have focused on impregnating the titanium implants with a factor that "homes" the bodys own regenerating cells to the potential growth site to create and build on a platform for new bone. This may eliminate the need to harvest bone from a non-injured site in the body for grafting into the site of injury, as is commonly performed now. It should be possible to harness the bodys natural tissue regeneration capacity to recruit the right cells to the site where new bone tissue is needed. (133) The rougher surfaces seem to improve the de novo bone formation due to the early surface adhesion of non-collagenous proteins like osteopontin and bone sialoprotein.(85)titanium serves as a well-documented bone-conductive material, and the combination of a titanium nano-structure added to other biocompatible materials, such as collagen as may be a strategic option to improve bone regeneration and engineering.(86) also, low-level laser stimulation creates a number of environmental conditions that appear to accelerate the healing of bone in vivo and in vetro investigations. (87, 88)Implant systems Features affect periimplant tissuesImplant geometry Until recently, the majority of threaded implants had a cylindrical (i.e. parallel-sided) shape. However, recently popular tapered shapes that more closely resemble tooth roots have been suggested to provide more optimal stress transfer into crestal bone.(89)Following osseointegration, the bone-to-implant interface of most threaded implants comprises a planar contact without undercut regions. As a result, these transverse force components are transferred primarily as compressive forces to the crestal bone opposing the implant surface forced against it.(90, 91) Additionally, the resulting stresses will be greatest in bone next to the most coronal implant thread tips. The resulting high-localized compressive stresses can lead to micro-fractures in crestal bone followed by resorption. This coincides with the fact that most crestal bone loss with traditional threaded implants occurs in the first year of function. Ways to reduce the high compressive forces acting on crestal bone with threaded implant designs would be to use longer implants, wider implants,(92) specific thread pitch heights especially in cancellous bone.(93) Tapered implant shapes, and micro-threads incorporated in to the implant neck, unlike most threaded implant designs, sintered porous-surfaced dental implants achieve integration by 3-dimensional bone ingrowth into and mechanical interlocking with the porous surface region formed by sintering. This type of bone-to-implant interface is able to provide resistance to interfacial tensile (upstream) forces. As a result, there is a more uniform stress distribution around the implant periphery with transverse force components being transferred to crestal bone at all implant aspects. This reduces the likelihood of micro fracturing and resorption of crestal bone.(90, 94, 95)Implant neck design Traditionally, the cervical or neck region of dental implants had a non-threaded, highly polished surface of sufficient height to accommodate biologic width without exposing much of the threaded implant segment meant to maintain implant fixation. Polished collar heights were generally in the range of 0.75 to 2.8mm. Remembering that establishment of biologic width required at least 1.5mm of linear implant surface from the micro-gap, polished collar height became more important with rough and moderately rough implant surfaces which ideally should remain buried in bone to avoid complications like peri-implantitis.(10, 96) Naturally, use of platform switching to add a horizontal component to biologic width allows shorter polished collar regions to be used successfully. However, another effective way to manage the implant collar segment is to add micro-threads to its geometry. Micro-threads offer two possible advantages.Firstly, their addition increases linear length of coronal implant surface available for biologic width and secondly allows some stress transfer in the coronal region superior to the macro-threaded segment of implant body.(97)This lower level of stress transfer to crestal bone is less likely to cause bone micro-fractures and reduces the probability for stress shielding and disuse atrophy of crestal bone as may occur with traditional polished implant collars. Both clinical and animal studies have documented good retention of crestal bone for implants with incorporated micro-threads(98).(99). Bone loss associated with coronally incorporated micro threads ranges from 0.11-0.18mm over 1 to 5 years.(98, 100, 101)Carrying a moderately rough texture all the way to the top of an implant has not been adequately confirmed to be beneficial, having a polished collar that is too long also may lead to unwanted bone loss. Al-Sayyed et al studied crestal bone loss in dogs around 2-piece, sintered porous-surfaced implants with either short (0.75mm) or long (1.8mm) collars.The short collared implants showed less bone loss, and the difference from long collared implants was linked to stress-shielding of crestal bone and disuse atrophy. (102).(103)Implant surface roughness Implant surface roughness may be classified as minimally rough, moderately rough, or rough. Machine-turned implant surfaces, as used on the original Brnemark-system threaded implant, are considered to be minimally rough(Sa - 0.5m) while, only plasma-sprayed surfaces, like those used on the original Straumann ITI implant or titanium plasma-sprayed press-fit implants, are classified as rough(Sa > 2.0 m). (104) The majority of contemporary threaded implant designs have what are considered moderately rough surfaces (Sa between 1.0 - 2.0m). Moderately rough implant surfaces have been shown to be more osteoconductive than minimally rough ones(105) and, as a consequence, require shorter initial healing intervals.(81, 106)Employing a moderately rough surface increases resistance to torquing forces once integration has developed .It may be one approach to improving implant outcomes in bone of lower density even with abbreviated healing intervals.(72)Rocci and colleagues compared anodized with machine-turned threaded implants that all were immediately loaded in posterior mandible locations. Implant failure rates were 14.5% for machine-turned and 4.5% for surface anodized implants. Mean marginal bone loss after 1 year of loading was similar (0.9 mm for surface anodized vs 1mm for machine-turned).(107)Aalam et al provided bone loss data for implants with surfaces roughened by anodization or dual acid etching compared to machine-turned implants at two years' post-loading. No significant differences were seen but a trend toward greater bone loss was seen with anodized implants, which had no polished collar.(108) Implant length and diameter Both length and diameter (width) of dental implants may influence marginal bone loss. Naert et al evaluated factors influencing marginal loss with machine-turned threaded implants functioning in partially edentulous patients for as long as 15 years. After 6 months in function, significantly (P=.03) more bone loss was observed as implant length increased. Implants in lengths of7mm, 13mm, and 18mm had annual bone loss of 0.02mm, 0.04mm and 0.05mm. Respectively, it was suggested that longer implants lost more crestal bone because they were more likely to have been placed in sites of predominantly alveolar rather than basal bone, the latter being more resilient to resorption. However, other identified factors may have played a role in this rather surprising outcome.(109) Rokni et al reported a similar negative correlation between crestal bone loss and implant length with sintered porous-surfaced, press-fit implants after 5 years function. Long implants (9 or12mm) had significantly greater crestal bone loss (0.2 mm more) than short implants (5 or 7mm). Others, however, have found that short threaded implants suffer more crestal bone loss than longer ones.(110)Like implant length, differing implant diameters have been associated with crestal bone loss. Multiple studies have demonstrated that increased implant diameter tends to be associated with reduced crestal bone(111, 112).Radiographic evaluation of dental implant European and American guidelines for implant therapies recommend that X-ray tomography of one tooth or a small area, or computed tomography (CT) of an area including multiple teeth, be carried out together with conventional radiography (intraoral radiography, occlusal radiography, panoramic radiography and lateral cephalometric radiography) as imaging diagnosis prior to implantation surgery(113). In particular, CT has been used for preoperative evaluation of bone quality(114), and in recent years there have also been reports of preoperative imaging diagnosis using magnetic resonance imaging (MRI) (115) However, applications of CT and MRI for postoperative imaging diagnosis aimed at monitoring the course following implantation still have problems such as artifacts and resolution. Moreover, for judging the prognosis after implantation, it is important to evaluate the relationship between the implant and the surrounding trabecular bone structure. It was also reported that secondary implant stability was increased due to bone formation and remodeling at the implant/tissue interface and in the surrounding bone. (116) A digital panoramic image, the same as all digital images, is an image that is composed of a large number of very small pieces of information known as pixels (picture elements). A specific number that corresponds to the brightness with which the pixel will be displayed represents each of the pixels in a digital image. This number is known as pixel value the pixel value corresponds to a specific shade of gray since all the images encountered are black and white. An analog- to-digital converter to a number assigning each pixel converted the electrical charge that is generated in each of the pixels after exposure. This number will eventually represent the pixel intensity value (shade of gray) of the specific location of the digital image. (117) Two-dimensional (2-D) digital radiography is considered a powerful diagnostic tool for simple and complex procedures. Recent advancements in digital imaging have reduced radiation exposure, increased resolution, and improved detection capabilities. The advantages of direct digital imaging in dental radiology were stressed. Digital modalities allow the dentist to perform mathematic operations for image enhancement and also take advantage of advanced techniques, such as geometric registration, digital subtraction, and computer-aided recognition of image features.(118) The use of dental radiographs is a potentially important means of determining change in alveolar bone. The value of radiographic measurements depends on both the reproducibility of geometric alignment of successive radiographs and the techniques used to analyze change including the repeatability of measurements.(119) Digital Subtraction of dental images was used to make the image contrast reflect the subject contrast and to emphasize the differences between two images.(120) It is a common assumption that panoramic image subtraction is impossible because of the large distortions that result from geometry misplacements among the serial images, but the feasibility of this approach by using computer-based image registration techniques has been demonstrated. (121) For implant treatment, planning and follow-up controlled panoramic radiography is commonly used rather than multiple intraoral radiographs. Under controlled standardized conditions, the potential of using digital subtraction techniques with panoramic images was demonstrated (122). The role of loading is likely to have increased influence in clinical situations with poor bone quality, insufficient bone for ideal load transmission, heavy occlusal function associated with parafunctions, and misfit of the prosthesis. (123) showed, in a dog experimental model, that implants placed without flap reflection remained stable and exhibited clinically relevant osseointegration similar to that observed when implants were placed with flapped procedures. Sennerby (124) reported a mean marginal bone loss of 3 mm. Of these, 14% experienced greater than 3 mm and 27% had more than 2 mm of bone loss. They found more bone loss in dental implants placed with flapless than with flap techniques. These results yielded were attributed to the attempt increase efficacy and effectiveness by using one-piece implants, flapless technique and immediate loading. X-ray assessment of peri-implant alveolar bone over 12 months was assessed using different techniques including peri-apical X-rays, panoramic radiography, CBCT and radiographic fractal analysis. Minimal bone changes over a short time can be monitored using digital intra-oral radiography. Radiographic fractal analysis did not appear to match histological fractal analysis and CBCT was not consistent for bone density measures, but might have potential in structural investigation of the trabecular bone(125) Many methods evaluating bone density have been introduced. Among them, histologic and morphometric measurements are the gold standard for the measurement of bone density.(126) These measurements include the Hounsfield unit using quantitative computerized tomography (127) or quantitative cone-beam computerized tomography, dual energy X-ray absorptiometry,(128) and magnetic resonance imaging(129) however, such methods are limited in that they cannot be applied to all implants clinically. (130) Bone quality is often referred to as the amount of cortical and cancellous bone in which the recipient socket is drilled, and lower bone density might compromise osteogenesis and stability or cause excessive resorption compared with higher density bone, thereby upsetting osseous healing(131, 132). Using computed tomography suggested that calibrated information on bone mineral density (BMD) may be used in dental implantology to measure bone quality (132) Using digital radiography with morphological filter system and a grayscale test assessment as a computer-assisted diagnosis for evaluating implant osseointegration was reported (116). In addition, in vivo experimental studies suggest that the implant holding properties increased with time as a result of osteogenesis in trabecular bone(133) A progressive tissue response over a long period of time also occurs. (1) Therefore, although there is a range of implant stability at installation, implants eventually achieve good stability clinically. Implant stability depends largely upon cortical bone thickness. (134) With the methodology named computer-guided implantology, anatomic limitations and bone quantity and quality can be evaluated precisely. The increased use of this method can be attributed to improvements in radiologic technologies and dental implant treatment planning and analyzing softwares. It is possible to pre-surgically determine the best position for implant placement and to plan the implant position and inclination, based on the final prosthetic outcome as well. . (135) Aim of the StudyThe aim of the present study was to evaluate clinically and radiographically the condition of periimplant tissue following flap and flapless dental implant placement. Patients and method Patients and methods 140 Patients and methods Ten patients, (three males and seven females) ranged in age from 25-45 years, were chosen from individuals who were referred to the Department of Oral Medicine, Periodontology, Oral Diagnosis and Radiology, Faculty of Dentistry, Al- Azhar University, Every patient received two implants placed in two bilateral similar edentulous sites in the same patient (split mouth design).Inclusion criteria:- Bilateral identical loss of posterior teeth in the mandible and required fixed restoration.- Presence of adequate bone width on both sides of the mandible for implant stabilization. precluding the need for bone augmentation procedures.- Compliance to control plaque around implants. Exclusion criteria:- General medical conditions contraindicating implant surgery.- Bone volume limited in width, height, or otherwise insufficient for bilateral implant placement in the posterior mandible.- Smoking.- History of previous periodontal disease. All patients provided informed consent prior to implant placement. In each patient, the left edentulous site of the lower molar region was selected to receive implant with flapless technique the opposite contralateral right edentulous site received implant with flap technique. The implant used in this study was tapered screw grit blasted acid etched micro threaded Xive plus implant*. Implants insertion procedures: Implant sites, left for flapless and right for flap were evaluated clinically by bone sounding procedure and radiographically for position of the implant placement prior to implant surgical procedure.Bone sounding procedure (ridge mapping): Figure (1) Analysis of study models for the mandibular bilateral edentulous sites to estimate the morphology of the alveolar process. The morphology of the alveolar process covered with mucosa agrees with that of the underlying bony layer. Therefore, it has been suggested to assess the size and shape of the alveolar bone by bone sounding (ridge mapping) (136). Following local anesthesia, the thickness of the mucosa is measured by penetrating the soft tissue with endodontic files with rubber stops one every 2 mm from the buccal to the lingual the measurements were recorded at various sites in the region. The study model was sectioned in correspondence with the implant sites and the soft tissue was delineated. Figure (2) By using the recorded measurements, the volume of the soft tissue was determined. The position and diameter of the implants were selected.*DENTSPLY. Friadent. GermanyFigure (1): Bone sounding procedure (ridge mapping).Figure (2): A study model was sectioned and the soft tissue was delineatedRadiographic evaluation for position of the implant placement The position of the implant placement was determined by the position of the depicted metal ball implanted within acrylic resin base. Figure (3) & evaluated by digital panoramic image. Figure (4) the metal ball, with known dimensions may be placed in the region of interest (ROI) making it possible to ensure equal magnification in both planes. (137)Figure (3): Metal sphere implanted within acrylic resin baseFigure (4): Digital panoramic image with a metal ball determining implant position and showing equal magnification. The implant system provides a radiographic transparent template Figure (5) that includes a set with the actual implant dimensions and another set with magnied images of the implant. The transparent template overlapped on the panoramic image Figure (6) to ensure actual position and selection of implant size. The preliminary evaluation of the panoramic image of the selected implant site relation anatomical structures as mandibular canal was evaluated. Figure (7)Figure (5): A radiographic transparent templateFigure (6): The transparent template overlapped on the panoramic imageFigure (7): Evaluation of the panoramic image of the selected implant site relation to mandibular canal with the measurement of the distance from bone level to the canal to be sure that the height selected is away and suitable.Implant surgical procedures All patients received antibiotic prophylaxis. Immediately before the procedure, the patient rinsed for two minutes with 0.12 chlorohexedine digloconate solutions. Both left and right areas were injected with local anesthetic. For the right flap site, Figure (8-A) crestal horizontal incision was made and the flap was elevated. Drilling of the bone was done at 600 rpm with copious internal and external saline irrigation and Xive plus implant was installed using Xive surgical kit and the ap was sutured using 3/0 braided silk*. *Mersilks, Ethicon, Johnson & Johnson, Madrid, Spain.For the left flapless site, a punch drill made Figure (8-B) mucosal punching for the standard (narrow/wide) diameter of implant then round drill was used to prepare the site and Twist drills in a chronological sequence with permanent internal cooling and Xive plus implant was installed. BA Figure (8): A: Crestal horizontal incision was made and the flap was elevated. B: Mucosal punching for the standard (narrow/wide) diameter of implant.No surgical guide was used for free-hand inserted implants because only single cases were treated. The implant platform was positioned at the alveolar crest level. All patients were included in a strict hygiene recall. All patient were recalled periodically at one month (base line) and also at 3, 6 months and one year after surgery for clinical and radiographic evaluation.The implant can be provided with a provisional restoration at placement, allowing for the mucosal epithelium and the connective tissue adhesion to form coronal to the alveolar crest (138) Clinical evaluationInfection, swelling and gingival inflammation were assessed using the gingival index (GI) according to Loe and Silness.(139) Probing Depth (PD) Figure (9-A&B) was measured according to a standard procedure described by Glavind and Loe (140) using periodontal probe with Williams calibrations. (141)BA Figure (9): A: Periimplant probing depth for flap right side. B: Periimplant probing depth for flapless left side. Patients were asked to answer a questionnaire with questions on a Visual Analogue Scale (VAS) Figure (10) measuring their opinion about the procedure; regarding discomfort and pain.(34)Figure (10): Visual Analogue Scale (VAS)Radiographic evaluation Standardized direct digital panoramic images were obtained using Planmeca Prolin XC* unit Figure (11) operated at 80 kvp, 7mA, 18s exposure time and total filtration 2.5 mm Al. with a constant equal magnification of 1.2 (moving axis of rotation). Exposure parameters were fixed during the follow up period for standardization.Figure (11): Planmeca Prolin XC unit.* Planmeca. Helsinki. finlanda To control the placement of the patient relative to the x-ray unit, as small differences in placement having large effects on resulting images so an acrylic bite block Figure (12) was fabricated for each the patient to bite each time at the same position during exposure for standardization of subsequent images. The triple laser beam system of the unit also adds to correct positions. The bite blocks were saved and reused for postoperative follow up at one month and three months and six months and one year. Periapical images Figure (13) were done when needed for detecting any subtle changes.Figure (12): Acrylic bite block for patient to bite each time at the same position during exposureFigure (13): Periapical image of implant. Direct digital panoramic images were exported and stored in JPEG (Joint Photographic Experts Group) file format. Radiographic image processing evaluation of bone level height (for bone resorption) & Density profile; computer assisted densitometric image analysis (CADIA) (for osteointgration) mesial and distal to the implant & Digital subtraction radiography (DSR). Windows based image processing softwares; ImageJ software * & Emago software ** were used for image evaluation. Image processing analysis: Bone level height: Bone level height was performed using ImageJ software. Bone height is set in a scale in relation to distance in pixels with the equivalent in mm. * ImageJ software; Ij 1.45m (http://imageJ.nih.gov/ij**Emago software; Emago/advanced version 5.7. Bone level height was measured Figure (14) A main reference line was identified along the long axis of the implant (red arrow). Another two reference lines were identified one at the apex and the other in relation to the upper border of the radioloucent vents perpendicular to the reference line (blue arrows). The level of bone was determined by the horizontal line on mesial & distal to implant and bone height was measured (yellow arrows). Figure (14): Diagrammatic representation of reference lines for level height measurement.Density profile (CADIA) & Digital subtraction radiography (DSR) Densitometric analysis was performed using ImageJ software. The density was evaluated after selection of the region of interest (ROI) which is the area mesial & distal to the implant along the sides. Figure (15) Images were subjected to histogram equalization excluding the minimum gray value (black or 0) and the maximum gray value (white or 256) as those values might not be a true representation of the gray value of the original image. Figure (15): Inverted image showing area of densitometric analysis mesial to the implant (blue line). Densitometric results were presented as mean gray value, integrated density & raw integrated density. Mean gray value is the average gray value within the selection. This is the sum of the gray values of all the pixels in the selection divided by the number of pixels. Integrated density is the sum of the values of the pixels in the selection. This is equivalent to the product of Area and Mean Gray Value. Raw integrated density is the sum of pixel values which is displayed under the heading Raw integrated density as Integrated density is enabled. Digital subtraction radiography (DSR): was performed between the original first image and the subsequent images using Emago software. Advanced image matching was performed which is a combination of Geometric registration, gray scale matching and subtraction. Geometric registration was performed to produce a pair of images with identical image formation geometry by mapping the information contained in one image onto the projection plane of the other image, which is considered a reference one. Subtraction is used to evaluate small changes between images which will be visible when the corresponding pixels were subtracted. The resulting image is empty when the gray values of the pixels in both images are the same but shows a brighter area (increased density) which means gain of material or darker area (decreased density) which means loss of material in those locations where the pixel values are different.Statistical analysisStatistical analysis was performed with IBM IBM Corporation, NY, USA. SPSSSPSS, Inc., an IBM Company. Statistics Version 20 for Windows. Data were presented as mean and standard deviation (SD) values. The present study is a split-mouth design; so paired t- test was used to compare between bone density and bone height measurements of the two techniques. Paired t-test was also used to study the changes by time in bone density and bone height measurements with each technique. Percentage changes in bone density, amount of bone loss, VAS scores data showed non-parametric distribution; so Wilcoxon signed-rank test was used to compare between the two techniques. This test is the non-parametric alternative to paired t-test. The significance level was set at P 0.05. Results Results ResultsClinical FindingsClinical findings showed that all implant succeeded there were no mobility, no effect on the adjacent teeth, no infection, no intrusion in the mandibular canal, patients reported high degree of satisfactionPeriimplant probing depth (PPD) Table (1) & Figure (16)The mean probing depth (PPD) of Flapless group was (0.77 0.31) at 3 months, (0.89 0.33) at 6 months, and (1.17 0.32) at 12 months, while Flap group it was (0.63 0.32) at 3 months, (0.91 0.56) at 6 months, and (1.06 0.32) at 12 months. There was no statistically significant difference between PPD of the two techniques through all periods.Table (1): The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between PPD of the two techniques TechniquePeriodFlaplessFlapP-valueMeanSDMeanSD3 months0.770.310.630.320.2346 months0.890.330.910.560.72512 months1.170.321.060.620.621*: Significant at P 0.05 Results Figure (16): Bar chart representing comparison between PPD of the two techniquesChanges by time within each technique: Table (2) Figure (17).Flapless technique: There was no statistically significant change in mean PPD after 6 months while after 12 months there was a statistically significant increase in mean PPD.Flap technique: There was a statistically significant increase in mean PPD after 6 months and 12 months. Table (2): The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean PPD of each techniquetechnique PeriodMean differenceSDP-valueFlapless3 months 6 months0.130.300.1813 months 12 months0.400.430.035*Flap3 months 6 months0.280.340.020*3 months 12 months0.430.370.017**: Significant at P 0.05Figure (17): Line chart representing changes by time in PPD of each techniqueComparison between percentages changes in PPD in the two groups: Table (3) & Figure (18). Flap technique showed statistically significantly higher mean % increase in PPD than flapless technique. Table (3): The mean %, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between percentages of change in PPD TechniquePeriodFlaplessFlapP-valueMean % SDMean % SD3 months 6 months15.65.844.415.60.005*3 months 12 months5125.468.321.70.043**: Significant at P 0.05Figure (18): Bar chart representing mean % change in PPD of the two techniquesGingival index (GI)Comparison between GI measurements of the two techniques: Table (4) & Figure (19).The mean Gingival index (GI) of Flapless group was (0.06 0.11) at 3 months,(0.50 0.41) at 6 months, and (0.33 0.35) at 12 months, while Flap group it was (0.08 0.18) at 3 months,(0.22 0.19) at 6 months ,and (0.17 0.17) at 12 months. There was no statistically significant difference between GI of the two techniques through all periods. Table (4): The mean, standard deviation (SD) values and results of Wilcoxon signed-rank test for comparison between GI of the two techniques TechniquePeriodFlaplessFlapP-valueMeanSDMeanSD3 months0.060.110.080.180.3176 months0.500.410.220.190.08812 months0.330.350.170.170.131*: Significant at P 0.05Figure (19): Bar chart representing comparison between GI of the two techniquesChanges by time within each technique: Table (5) & Figure (20).Flapless technique: There was a statistically significant increase in mean GI after 6 months and 12 months.Flap technique: There was no statistically significant change in mean GI after 6 months and 12 months. Table (5): The mean differences, standard deviation (SD) values and results of paired t-test for the changes by time in mean GI of each techniqueTechnique. PeriodMean differenceSDP-valueFlapless3 months 6 months0.440.410.027*3 months 12 months0.280.290.023*Flap3 months 6 months0.140.250.1293 months 12 months0.080.180.180*: Significant at P 0.05Figure (20): Line chart representing changes by time in GI of each techniqueComparison between percentages changes in GI in the two groups: Table (6) & Figure (21). Flapless technique showed statistically significantly higher mean % increase in GI than flap technique. TechniquePeriodFlaplessFlapP-valueMean % SDMean % SD3 months 6 months733.3435.2175.282.4