13- overdentures

8/9/2019 13- overdentures

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OVER DENTURES – HYBRIDS

Tooth supported complete dentures

Definition

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Introduction

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History

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Indications, contraindications

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Rationale for over dentures

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Examination, diagnosis treat planning prognosis

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Periodontal considerations

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Endodontic considerations

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Types c lassification (depending on the method of

abutment preparation coping abutments attachment

a! "verdentures for congenital and ac#uired defects

b! Transitional overdentures

c! Immediate overdentures


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d! Remote overdentures

e! $ro%n&sleeve coping prosthesis

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$entric relation chec' points

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Post insertion instructions and complications

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Denture problems

↓dvantages and disadvantages

Definition

n overdenture is a complete or a par tial denture

supported by mucoperiosteum and prepared teeth!

tooth supported complete denture is a dental

prosthesis that replaces the lost or missing natural

dentin and associated structures of the maxillae and)or

mandible and receives partial support and stability from

one or more modified natural teeth!

removable partial denture or complete denture that

covers and rests on one or more remaining natural teeth,


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the roots of natural teeth and)or dental implants (*PT

+!

Introduction

Prevention is better than cure- . this phase is heard

time and again in a medical and dental profession!

I can thin' of no other better example of preventive

dentistry than the use of an "/ER DE0T1RE-!

Indications

Denture opposed by natural teeth or a removable partial

denture, because able resist increased occlusal forces

exerted by opposing natural teeth!

Patients %ith congenital or ac#uired defects!

Patient %ith fe% teeth remaining and it is understood

that patient %ill have difficulty in adapting to complete

dentures (e!g! Par'inson2s disease!


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3hen remaining teeth are considered unsuitable as

partial denture abutments because of position,

angualtion and state of cro%ns!

3hen the prognosis of the teeth because of mobility is

poor! This mobility can be decreased in the cro%n root

ratio!

In cases of tooth surface loss due to attrition, abrasion

or erosion may be used as abutment for over dentures!

4or patient %ith poor prognosis for complete dentures!

& Palatal vault is high and ridges slope

& 5andible has a poorly defined subl ingual fold,

floor of mouth drapes

ontraindications

Patient %ho lac' motivation

Teeth that cannot be saved by periodontal and

endodontical therapy!

Remaining natural teeth are ade#uate to restore dental

arch %ith fixed or removable partial dentures!


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Rationale for retention of teeth for o!er dentures concept

6efore I tal' about proprioception I %ould add a note

on receptors %hich are responsible for this receptor is a

nerve terminal that responds to stimuli!

Receptors are classified (Ramford and sh

Exteroreceptors . affected by changes in external

environment (stimuli, temperature, vision, hearing

Interoreceptors . respond to the changes in the visera

(Hinger, visceral pain, thirst

Proprioreceptors . concerned %ith sense position and

movements of body and its parts (ligaments, muscles,

tendons!

"roprioception #$"T – %&

Definition

The reception of stimulation of sensory nerve terminals

%ithin the tissues of the body that give information

concerning movements and the position of the body!


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Sensor' input from periodontal receptors

7ensitivity of anterior teeth

The minimal threshould for detection of load %as 8gm

on the incisal surface of anterior teeth (axial direction

and 9 to 8:gm on the occlusal surfaces of molars, but in

individual %earing dentures i t %as ;


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Aerge (8?Ba% movements during mastication!

Proprioception and salivary secretion

Capur and $oll is ter (8?+: said tha t periodontal

receptors played an indirect role in the masticatory

salivary reflex by regulating the range and type of

masticatory stro'e!

In denture %earers there is impairment of the

mechanism of regulating parotid gland stimulation

during mastication!

Tooth mobility in reduced teeth


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Reduction %ill improve cro%n . root ration and reduce

the mobility of retained! The mobility is reduced from

8:: to B:!

(l!eolar )one preser!ation in o!er dentures

The alveolar bone loss in anterior part of mandible in

overdenture %earers %as :!Bmm and in the case of

conventional dentures in ;!=mm almost 9 times more!

E*(+IN(TION, DI($NOSIS, TRE(T+ENT

"-(NNIN$ (ND "RO$NOSIS

./ Histor'

Medical history

Debilating diseases

& Diabetes

& Hypertension

& HI/, Hepatit is 6

Psychiatric disorders

Dental history


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Past dental experience, influence is attitudes

motivation, expectation!

Reasons for loss of tooth

Pre treatment records

Photographs

$asts

Profile registrations

$ephalometric radiographs

Examination

/isual examination . for any pathologic changes

Rigital examination

& 7harp mylohyoid ridges

& Exoteses

& Disposable tuberosity t issues

& 1ndercut areas

Dental examination

ny resin, caries, occlusion, denture space, habits


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Inflammation . recession, attached gingiva, poc'ets,

bony deformitive

& Periodontal examination

& Radiographic examination . I"P, "P*

Dia0nosis

The propectine po%er denture patients have chronic

generalied periodontitis, congenital deformities, or loss of

teeth due to trauma!

Treatment plannin0

"ver dentures is considered as treatment of choice if

four or fe%er retainable teeth are present, %hich are mobile,

improper cro%n root ration, %here removable partial denture

and fixed partial denture are not recommended!

()utment selection

Evaluat ion of abutment teeth should be evaluated

carefully from vie% points!


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8! Periodontal status . minimal mobility, acceptable bone

support, ade#uate band of attached gingiva!

=! $aries activity . minimal or no caries activity!

endodontic treatment contributes abutment tooth and

replacement %ith one of the similar sie and shape!

$ro%n root ratio2s improved after endodontic treatment!

@! Posit ional considerations . teeth should be retained

%here the occlusal force on the residual ridges has the

greatest destructive potential! Ideally t%o canines and

t%o premolars area act as 'eystone of the arch! T%o

canines and a central incisor . tripod of heavy

techni#ue! ngulation of the tooth should considered!

The root should be perpendicular to direc tion of

occlusal forces!

;! Path of insert ion . tooth that is retained causes an

undercut in the labial contour of the ridge that %ould

not persist in case the tooth is removed! The retention

of premolar or incisors may protect the out part of the


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arch or relief can be given or the borders can be under

extended!

"eriodontal considerations for an o!erdenture patient

Presence of healthy teeth in the mouth is essential for

maintaining the alveolar ridge!

$anines are the most favorable teeth in the arch as they

have a larger surface area for attaching the periodontal

fillers!

"sseous defects are usually not found in amount portion

of the >a%s since the cortical plate and alveolar housing

often are fused %ithout any spongy bone!

"eriodontal therap'

Includes elimination of periodontal poc'et increase the

>one of attached gingiva, increase depth of the vestibule

and correction of any osseous defects! 5aintenance of

abutment teeth %ith good oral hygiene procedures!

omplications


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Irritation from the denture base, pressure atrophy due to

inade#uate inlay relief of the overdenture

Poor oral hygiene

Periodontal abscess

Endodonitc considerations

Endodontic treatment is a must for teeth %ith mobility

as the cro%n&root ration cannot improved!

The important to select abutment %ith the single root

canal!

"ne visit endodontic therapy that is usually follo%ed,

increase of periapical infection it is contraindicated!

Endodontic implants

It is used to stabilie teeth %ith extremely short roots or

excessive bone loss! 7pecial instruments . @:mm

intraosseous bone drills!

"rocedure – use of ru))er dam, anesthesia


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Removal of the incisal third to half of clinical cro%n to

allo% access to pulp chamber and root canal!

Preparation is to =&


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5any patients %ith congenital and ac#uired defects

cannot be treated successfully by orthodontic therapy or

surgical intervention!

$ongenital defects

The cleft palate

"ligodontia

5icrodontia

Dentiongenesis imperfecta

(c1uired defects

ccidents

5isuse

"ral cancer

"rocedure

Impressions are made of both the arches using stoc'

trays and irreversible hydrocolloid!

The cast placed on the surveyor to determine the path of

insertion!

1ndesirable undercuts are bloc'ed out!


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6ase plates are made using autopolymeriing resin by

sprin'le on method!

5axillomandibular relationship record made by tactile

method!

The teeth of proper mold and shade are selected and

ground on the lingual aspect to overlay the existing

teeth!

The dentures are %axed and processed in the

conventional manner!

Transitional o!erdentures #Interim o!er denture&

It made from an existing removable partial denture, the

patients o%n teeth or both!

n existing removable partial denture is most common

indication for an interim over denture!

Procedure

Endodontic therapy is completed before modifying teeth

or the removable partial denture!


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Evaluate the existing removable partial denture and

natura l cro%ns to ensure tha t they have ade#uate

strength!

5a'e an index that relates all cro%ns to the occlusal

surface of the removable partial denture!

Chair side procedures

Prepare the retained teeth! Remove each cro%n in on

piece and save it!

5a'e an alginate important %ith removable partial

denture in the mouth!

Laboratory procedures

Remove the roots of extracted teeth and prepared

retention holes in the cro%n that they can be

mechanically retained!

$ut off the s tone tee th on the cas t and re la te the

removable partial denture to the cast add the necessary

teeth using the occlusal index by sprin'le on method!

"ost insertion care

"ral hygiene instruction


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Regular visits for maintenance

Advantages

Fess costly

Patient experience %ith overdenture usually allo%s

smooth transition to over denture status!

Disadvantages

6order extension, esthetics, occlusion, support and

stability of removable partial denture are unsatisfactory

often many years of use!

1se autopolymer resin results in %ea'er over denture!

Immediate o!erdentures

n immediate over denture is an over denture

constructed for insertion immediately after the removal of

natural teeth!

butment selection


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Pretreatment recorded.measurement made from the

gingival margin of an abutment to the tooth in the

opposing arch %hen the >a%s are closed!

Treatment plannin0

If the arch contains large number of hopeless teeth, the

post hopeless teeth are removed in increments at least B

%ee's are allo%ed for healing before imp! Hopeless anterior

teeth are retained for esthetic prere#uisite endodontic and

periodontic treatment can be completed in healing period!

Impressions

1s t method

lgimate implant is made! $ast is poured . custom tray

is constructed on the cast over the teeth and residual ridges!

It used in ma'ing final imp %ith alginate or rubber base!

nd method

$ustom tray is fabricated on the edentulous portion of

cast, border moulded imp made %ith Ginc oxide eugenol!

This imp replaced in mouth and alg inate irrevers ible

hydrocolloid imp made!


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Aa% relations . not enough teeth present for orienting

casts base p la tes are fabricated to fac il ita te >a%

relationships!

7electing and positioning of teeth . by removing one

teeth on the cast and substituting the corresponding the

replacement for compression all teeth are removed

except the abutment!

butment is prepared on the cast to


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4luoride application . =&8minture application of P4

gel follo%ed, =&8minute application of :!@ stannous

fluoride!

7urgica l procedures . extension, frecnectomy,

tuberosity, reduction, undercut correction etc!, & sutures

placed!

Insertion of overdentures . provides excellent

protection for surgery side sutures removed in < . ;

days!

(daptin0 o!erdentures to a)utment

butment teeth should be polished before adapting the

over dentures!

Definite circumferential margin is made around each

indentations!

utopolymeriing resin is placed in the abutment

indention the abutment is %ell lubricated and vent is

placed for the excess to flo% out and the denture is


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placed in the mouth until initial set then placed in %arm

%ater!

"ost insertion care

!ral hygiene instruction

6ubble gum therapy . after a %ee' .


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Preparation of teeth to serve as abutment2s results in

exposure of considerable amount of dentin! $oping provides

some protect ion against car ies! $opings also pressure

abutment contours %hich can be modified!

Improper brushing

6ruxisim

"reparation of a)utment

The incisal or occlusal surface of coping is convex

(5iller 8?;9!

Provides a rounded contact bet%een coping and metal

base!

Endodontic, per iodontic and surgical procedures

completed before preparation!

The clinical cro%n should be reduced =!


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7hort do%el is placed in prepared root and for retention

(;.+mm

parallel tapered groove is placed on the buccal or

lingual surface of canal preparation to contour

rotational force!

The entrance of canal preparation is beveled to

eliminate sharp edges!

2a3 patterns

$ontour of coping is descr ibed as Hemispheric-

rounded occlusally and incisally! 3ax on occlusal surface

and incisal surface in copings are prepared %ith type III

gold!

Impressions (broader molding and rubber base are

made %ith ne%ly prepared coping!

Tooth selection and positionin0

The resin teeth for the abutment are selected hollo%ed

%ith a bur and positioned over the abutments!


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"pa#uing the metal base . pin' color to part of denture

base to covered by base resin!

The metal base cemented to the cast . >ined

oxyphosphate! Pac'ing the over denture and finishing

and polishing!

Advantages

Inherently stronger

Resist dimensional changes associated %ith

polymeriation of denture resins!

5etal base is excellent for >a% relation procedures!

Dentures supporting tissues respond more favorably!

Disadvantages

Relining presents more technical problems

5ore t ime consuming . addit ional laboratory and

clinical procedures

4(2 RE-(TION REORDS

"unctionally generated path techni#ue $Meyer% 1&'&(

5axillary dentures opposed by natural dentin!


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The opposing arch is restored first %ith fixed or

removable partial denture!

5a'ing the compound rim

The blac' imp compound, is used to form occlusal rim!

The compound rim sealed to resin base plate to prevent

separation!

The compound rim softened by flaming!

The mandible stone teeth lubricated and art iculator

closed to form distinc t indentation2s!

The compound rim cooled, remove the compound on

each side of the ridge formed by the central fossa!

$ompound removed on the anterior position (8 . =mm!

Recordin0 cuspal path

fter cuspal path %ax added to compound rim, patient

as'ed instructed to execute centric closures, as %ell as

protrusive, right and left lateral movements!

Procedures condt until smooth cuspal path is exhibited!

Pouring the path!


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The base plate and path rinsed thoroughly in cool %ater,

placed on cast, sealed %ith %ax and remounted in

articulator!

Then cuspal path is boxed stone poured and mounted to

lo%er lo% of the ar ticulator!

(daptin0 denture teeth to the core

The %axed denture teeth is replaced on the cast and

adapted to the core by using thin articulator stripe as an

indicator!

"ver dentures constructed by this techni#ue exhibit

excellent functional harmony!

entric chec5 point procedure

Effective method to verify accuracy of >a% relation

records (6re%er 8?B


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The centric chec' points are attached to the base plates

by removing all traces of occlusion rim!

7et of centric chec' points consists of

& three short point

& three long poin ts

& three med points

& three short cups

& three long cups

& %rench

$entric chec' point is assembled %ith long cup onto the

short point! The long point is scre%ed into the float end

of the long cup med point is used if the inter arch space

is nor sufficient!

"ne is placed in the midline and other in the molar

area! They are slanted slightly to%ard so that the points

are in line %ith arch of closure!


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7hort point is attached to max base plate long point to

mand base plate %ith imp compound!

Each cup is then rotated %ith %rench until the short

point is freed articulator opened each cup rotated off!

Then base plate is removed from the articulator and

placed in the patient mouth and centric relation is

chec'ed if the tips of the point should coincide it is

certain that the mandible is in centric relation!

"ost insertion care

!ral hygiene instructions

$hair side advice is soon forgotten %ritten instruction

best! Remove the denture before the retire at nite!

Recommended 8?B9 academy of denture prosthetics!

Readymade fluoride gel carrier!

Disclosing tablets

Care of abutment

Patients %ho lac' agility!

$hild tooth brush . easy to gain assess


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7oft %ebless rubber polishing cup

!ver denture hygiene

Removing after each meal %ith soft brush and ordinary

hand soap!

t nite removed and 'ept in denture cleansing solution!

7mall ultrasonic denture cleaner available!

Complications

8! $aries . because of recession

=! Inade#uate oral hygiene . symptoms of severe

periodontal disease %ill be present!


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& 6etter service than alternative method of

treatment!

& 1seful in pa tient congenita l abnormalit ies and

class III not amenable to surgical or orthodontic

procedure!

& Restore occlusion and improve esthetics by proper

positioning!

& Patient has fe% remaining teeth %hich ade#uately

supported by bone!

7implicity of construction!

& 7ome conventional $P

Ease of maintenance

7tability . comparable to fixed partial denture

Retention . 6ecause better stability

"pen palate possible

Excellent patient acceptance . 6ecause 'no%ledge that

he still has his o%n teeth!


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Fess trauma to supporting tissues . void resorption as

$P

7tabiliation of existing structures . as no resorption

vertical dimensions and lip and face maintained!

13- overdentures

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