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الكلية كلية طب الاسنان
القسم ترميم ومعالجة الاسنان
المرحلة 3
أستاذ المادة احمد غانم مهدي الهلال
4/19/2011 5:05:23 PM
Definition:
It’s the art and science that deals with restoration and replacement of a damaged tooth or tooth with crown the replacement and restoration of teeth by artificial substitutes that are not readily removable from the mouth. Its focus is to restore function, esthetics, and comfort.
Contents:
1. Retainer: it is the part that is cemented on the abutment teeth which is either extra or intracoronal.
2. Pontic: it is the part that presents the missing natural teeth and restores function and esthetic.
3. Connector: which connect the Pontic to the retainer, it could be rigid (solid) or non rigid (movable) connector.
A- Rigid connectors: it’s of three types: cast, soldered or loops.
B- Non-rigid connectors: it’s used either as stress breaker or to accommodate misaligned abutments, it’s composed of male (Tenon) and female (Mortise) parts.
Crown root ratio:
Is the measurement of the length of the tooth occlusal to the cervical margin compared to the length of the root embedded in the bone.
The ideal measurement to be used is 1:2 as abutment tooth, and the minimal ratio is 1:1.
ANTE S law:
The root surface area (pericemental area) of the abutment teeth more or equal to the pericemental area of the missing teeth.
Types of crowns:
1. Complete crown (full veneer crown): this type covers all the coronal portion of the tooth e.g. full metal, full metal with facing, porcelain fused to metal, porcelain or acrylic jacket crowns.
2. Partial crown: it covers part of the crown of the tooth e.g. ¾ crown and 7/8 crowns.
3. Post crown: it’s completely restores the coronal portion of the tooth and it retains itself by means of post extended inside the root canal of the tooth.
Types of bridges:
1. Fixed-Fixed bridge:
It s the most commonly used anteriorly and posteriorly. The Pontic or pontics are connected rigidly by solid joint to the retainer at both ends of the bridge, so we have only one path of insertion.
2. Fixed-Movable bridge:
The pontic is attached to a fixed retainer while the other side is movable joint which is connected with the other retainer.
It s useful in cases of tilted teeth where a common path of insertion can t be obtained and also a drifted abutment teeth that difficult to have the parallelism between the abutment teeth.
3. Cantilever bridge :
A. Simple cantilever:
Usually consist of one retainer, that’s mean one abutment tooth on one side only, it s usually indicated in missing lateral or premolar.
B. Spring cantilever:
The pontic is connected to gold bar which also connected to a retainer away from the pontic, it s usually used in case of missing maxillary central or lateral on one side of the maxillary arch with the presence of distance between the anterior teeth.
The forces applied are absorbed by the spring, it s usually not advised to be used on lower arch.
4. Resin bonded bridge (R.B.B): (conservative bridge)
There is minimal preparation within enamel, it s used for short span (3 units), less retentive than other types and we use composite as resin for cementation the abutment tooth.
Contraindication of R.B.B. :
1. Heavy occlusion.
2. Decreased over jet.
3. Attrition.
4. Long span.
5. Edge to edge.
Indication of FPD:
1. Restore function and esthetic.
2. Restore speech and phonetics especially in lower anterior teeth.
3. Prevent over eruption and drifting of apposing and adjacent teeth which may lead to premature contact or TMJ disorder.
4. Recontouring of occlusion, tooth surface, proximal contact with the adjacent teeth, and prevent food impaction.
5. Act as space maintainer.
6. Correction of disharmony exists between teeth and TMJ.
7. Periodontal splinting, the FPD can be used to stabilize the tooth in a condition that will prevent an increase in mobility but not eliminating it. There must be healthy abutment teeth.
8. The FPD can be used after orthodontic treatment to replace missing teeth.
Contraindication of FPD:
1. Long span edentulous area.
2. Free end extension.
3. Abutments with unstable bone support.
4. Short interjaw space and short teeth.
5. Patient with excessive bone loss especially in the visible anterior teeth because the bridge will have unacceptable appearance.
6. Age of the patient, FPD is preferred to be done in the age (after) 18 years since before this age the teeth have large pulp and not fully erupted.
7. Patient with dry mouth create a poor environment for FPD because of great risk of recurrent caries.
8. Occupation and habit limitation affect treatment.
9. Financial limitation.
Steps of crown and bridge construction:
1. Diagnosis and diagnostic caste.
2. Teeth preparation.
3. Impression making.
4. Bite registration.
5. Temporary (provisional) restoration.
6. Construction of working model.
7. Mounting of upper and lower models on articulator.
8. Waxing.
9. Investing.
10. Wax elimination.
11. Casting.
12. Finishing and polishing.
13. Cementation of restoration.
14. Follow up.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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