occlusal schemes in complete denture
TRANSCRIPT
OCCLUSAL SCHEMES
IN COMPLETE DENTURE
Muneeb Muhammed AliRoll No:47
III BDS
INTRODUCTIONOCCLUSION:
Occlude means to “CLOSE” “The static relationship between the incising or
masticating surface of the maxillary or mandibular teeth or tooth analogues” (GPT 8)
It is important to plan occlusal scheme prior to selection and arrangement of artificial teeth
Requirements of complete denture occlusion:Cutting,Penetrating and shearing efficiency of occlusal
surface
Minimum occlusal contact areas
Reduced posterior cusp height to control horizontal forces
Reduced buccolingual width of posterior teeth to decrease forces transmitted to residual ridge
Stability of occlusion at centric relation position and in area forward and lateral to it
Stability of occlusion in centric and eccentric relations
Balanced occlusal contacts
Types of complete denture occlusion
Balanced Occlusion
Monoplane Occlusion
Lingualized Occlusion
BALANCED OCCLUSION:-“The bilateral,simultaneous,anterior and
posterior occlusal contact of teeth in centric and eccentric positions” (GPT8)
It is not seen in the natural teeth,if it occur in natural teeth it is considered as premature contact on non working side and considered as pathologic
It enhances the stability of denture
Balance in complete denture is unique and man made
Types of balanced occlusion1.Unilateral lever balance2.Unilateral occlusal balance3.Bilateral occlusal balance4.Protrusive occlusal balance
Unilateral lever balance:-This is present when there is equilibrium of the base on its supporting structures when a bolus of food is interposed between the teeth on one side and a space exist between the teeth on the opposite side
Bilateral occlusal balance• This is present when there is equilibrium on both sides of denture due to
simultaneous contact of teeth in centric and eccentric occlusion
• It requires a minimum of a three contacts for establishing a plane of equilibrium,the more the contacts the more assured equilibrium
Unilateral occlusal balanceThis is present when the occlusal surfaces of teeth on one side articulate simulataneously as a group with a smooth uninterrupted glide
Protrusive occlusal balance• This is present when the mandible moves essentially forward and
the occlusal contacts are smooth and simultaneous in the posterior both on right and left sides and on anterior teeth
• It is slightly different from bilateral balance in that it it requires a minimum of three contacts (one on each side posteriorly and one anteriorly)
Factors affecting balanced occlusion1.Condylar Guidance
2.Incisal Guidance
3.Plane of Occlusion
4.Compensating Curves
5.Cuspal Inclination
1.Condylar Guidance“The mechanical form located in the upper posterior region
of an articulator that controls movement of its mobile member (GPT8)”
Increase in condylar guidance will increase the jaw separation during protrusion.this factor cannot be modified,so in patients with steep condylar guidance incisal guidance is decreased to prevent the posterior jaw separation
2.Incisal Guidance“The influence of the contacting surfaces of the
mandibular and maxillary anterior teeth on mandibular movements” (GPT8)
Incisal guide angle:-The angle formed between horizontal plane of occlusion and a line drawn in the sagittal plane between the incisal edge of the maxillary an mandibular central incisors when the teeth are in maximum intercuspation
It is determined by dentist during anterior try in
it should never be greater than the condylar guidance
3.Plane of occlusion“The average plane established by the incisal and occlusal
surfaces of the teeth.Generally it is not a plane but represents the planar medium of the curvature of these
surfaces” (GPT8)
It is established anteriorly by the height of the lower canine and posteriorly by the height of the retromolar pad
4.Compensating Curves“The anteroposterior and lateral curvatures in the
alignment of the occluding surfaces and incisal edges of the artificial teeth that are used to develop a balanced
occlusion”1.Anteroposterior compensating curve (curve of spee):-
“The anatomic curve established by the occlusal alignment of the teeth,as projected onto medial plane,beginning with the cusp tip of the mandibular canine and following the buccal cusp tip of premolar and
molar teeth continuing through the anterior border border of the mandibular ramus,ending with the anterior most portion of the
mandibular condyle” (GPT8)
Described by Ferdinand Graf Spee in 1890
• Signifance of curve of spee is when the patient move s his mandible forward,the posterior teeth set on this curve will continue remain in contact,thus avoiding disocclusion
2.Lateral Compensating curves1.Curve of Monson:- ”Curve of occlusion in which each cusp and incisal edge touches or conforms to a segment of the surface of a sphere 8 inches in diameter with its diameter with its centre in the region of glabella” (GPT8)
2.Reverse Curve or Anti monson curve:A cuve of occlusion that is convex upwards and usually used to arrange the first premolars
3.Curve of Wilson: This curve that is convex downwards .the lower teeth are inclined lingually giving prominence to buccal cusps and bringing them into heavy occlusal contact with the upper buccal cusp during lateral movement on working side
4.Pleasure Curve:- This combination of monson and anti monson curves .hence it is not single curve but combination of curve
It was used for arranging non anatomic teeth in balanced occlusion
5.Cuspal Inclination“The angle made by the average slope of a cusp with the cusp plane measured mesiodistal or buccolingually.also
called as Cusp Angle”(GPT)
It is an important factor that modify the effect of plane of occlusion and compensating curves
Mesiodistal cusps are reduced to prevent the locking of cusps
Advantage:- Bilateral simultaneous contact help to seat the denture in a stable
position during mastication,swallowing and maintain retention
Denture bases are stable even during bruxing activity
Cross arch balance
Disadvantage:- It is difficult to achieve in mouths where an increased
vertical incisor overlap is present-class II Cases
It may tend to encourage lateral and protrusive grinding habits
A semi adjustable or fully adjustable articulator required
MONOPLANE OCCLUSION“An occlusal arrangement where in the posterior
teeth have masticatory surfaces that lack any cuspal height”(GPT8)
Occlusal arrangement using non anatomic teeth
Anterior teeth are arranged with an overjet of 2mm and no overbite
Monoplane occlusion can be balanced by placing balanced ramps distal to second molar,it will improves horizontal stability of denture
Ramps
Advantage:-They are more adaptable to unusual jaw relation such as
class II and class III relationsEasy to arrange teeth and less time consumingThey eliminate horizontal forces,more damaging than
vertical forcesThey accommodate better to the negative change in the
ridge height that occur with agingSimple non adjustable articulator is sufficient
Disadvantage:-No vertical Component to aid in shearing during
masticationLack of positive intercupationPoor Appearance
LINGUALIZED OCCLUSION“This form of denture occlusion articulates the maxillary lingual cusps with the mandibular occlusal surfaces in centric working
and non working mandibular positions” first described by S Howard Payne in 1941 (GPT8)
Lingualized occlusion can be a type of bilaterally balanced occlusal cheme
Anatomic tooth are used in maxilla opposing a flat cusped or shallow cusped mandibular tooth
Forces directed towards lingual side
Maxillary lingual cusp articulates with mandibular central fossae
Advantage:- Cusp form is more natural in appearance compared to non anatomic forms Good penetration of bolus is possible this may reduce the lateral chewing
component Both anatomic and non anatomic tooth forms are retained Simple technique Can be used in Class II,Class III,IV And cross bite situations
Disadvantage:- Wearing of maxillary lingual cusp or mandibular fossa More challenging teeth arrangement than monoplane occlusion
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