Lecture 06 - Occlusal Analysis PDF

Occlusal analysis and adjustment DR. Sara Zaky Mohamed Associate professor of Prosthodontics  Definitions Occlusion is "the static relationship between the incising or occlusal surfaces of the maxillary or mandibular teeth or tooth analogues. The occlusion should be balanced and as...

Occlusal analysis and adjustment DR. Sara Zaky Mohamed Associate professor of Prosthodontics  Definitions Occlusion is "the static relationship between the incising or occlusal surfaces of the maxillary or mandibular teeth or tooth analogues. The occlusion should be balanced and as stress free as possible".. OCCLUSION FUNDMENTALS  Among the numerous local and systemic factors with the potential to influence the progression of periodontitis, the patient’s occlusion remains a variable that requires an exact diagnosis Occlusion becomes a factor for consideration when the occlusal forces acting on a tooth produce displacement of the root in the socket which results in an injury to the supporting periodontal ligament. This periodontal tissue injury from occlusal forces has been defined as the lesion of trauma from occlusion. the microscopic changes include increased vascularization, increased vascular permeability, vascular thrombosis, and disruption of fibroblasts and collagen fiber bundles. If the force is maintained, osteoclasts appear on the surface of the alveolus, leading to net bone resorption. 3  Occlusion The teeth and their periodontium are subjected to functional dynamic loading during chewing, swallowing, and the performance of parafunctional habits, including bruxism and clenching. Tooth contact is minimal during speech. 4 5 6  Harmonious occlusal Harmonious occlusal force on a tooth stimulates the physiologic arrangement of its periodontal attachment fibres and its osseous architecture and encourages its stability. Forces that exceed the tolerance of the periodontium result in resorption of the bone and disruption of the attachment 7  Occlusion types A physiologic occlusion is present when no signs of dysfunction or disease are present, and no treatment is indicated. A non-physiologic (or traumatic) occlusion is associated with dysfunction or disease caused by tissue injury, and treatment may be indicated. A therapeutic occlusion is the result of specific interventions designed to treat dysfunction or disease 8  OCCLUSAL FUNCTION & DYSFUNCTION The identification of masticatory system disharmonies allows the clinician to recognize dysfunctional relationships, which may influence the accuracy of the diagnosis. Stability is enhanced by the simultaneous bilateral contact of multiple posterior teeth with occlusal forces in the long axis of most posterior teeth. 9  PARAFUNCTION Bruxism : an oral habit consisting of involuntary rhythmic, nonfunctional grinding or clenching of teeth, in other than chewing movements of the mandible, which may lead to occlusal trauma. Common cause for attritional wear, loose teeth, fractured cusps, alveolar exostoses and muscle pain. Bruxism may cause occlusal forces on teeth that are susceptible to periodontitis to be increased in intensity or frequency, thereby magnifying the potential damage. In the case of a sustained, low-level force, the amount of deformation of the periodontal membrane increases with the passage of time, causing ischemia. Repetition of this ischemic condition may affect the resistance of the periodontal issue. 10 11  BRUXISM AND PERIODONTAL DISEASE Bruxism does not initiate gingivitis or pocket formation. The most frequent results of bruxism are compensatory hypertrophy of the periodontal structures and increase in width of the periodontal membrane. When there is pre-existing gingival inflammation and particularly when there is some loss of tooth support, the weight of evidence suggests that bruxism probably accelerates the destructive process, as does any other form of secondary occlusal trauma. 12  CLINICAL EXAMINATION A comprehensive evaluation of masticatory system and muscles and occlusal anatomy is a prerequisite to identify any occlusal disharmony. Clinical assessments to be done are A- TMJ evaluation B-Testing for mobility of teeth C- Centric relation assessment D-Evaluation of excursions E-Articulated diagnostic casts 13 Evaluations Temporomandibular disorder screening evaluation 1. Maximal opening (range = 40- 50mm) 2. Opening / closing pathway 3. Range of lateral and protrusive excursions (≥ 7mm to 9mm) 4. Auscultation for TMJ sounds 5. Palpation for TMJ tenderness or tissue displacement 6. Palpation for muscle tenderness 7. Load testing of the patient’s TMJs Will be discussed in full details in TMJ lectures 14  Testing of mobility of teeth Manual evaluation of mobility is best carried out clinically using the handles of two instruments to move the teeth buccally and lingually. Fremitus : is the movement of a tooth or teeth subjected to functional occlusal forces, this can be assessed by palpating the buccal aspect of several teeth as the patient taps up and down. Peri odontometers to standardize the measurement of even minor tooth displacement. 15  Study of the mounted diagnostic Casts Study of the accurately mounted diagnostic casts can reveal occlusal discrepancies between initial contact in the centric relation closure arc and maximal intercuspation and occlusal disharmonies in excursions. 16  Techniques used for detection of occlusal disharmony Commonly used techniques are Articulating Paper Foils/Ribbon - is commonly used in clinical and laboratory settings to mark premature contacts in the occlusion. - This produces marks on the teeth representing either high force or premature contact. CONVENTIONAL TECHNOLOGIES 17  2- Silk strips They are available in average thickness of 80μ and are soft flexible indicator materials, which are reliable because of their texture and do not produce pseudo contact markings by adapting perfectly to cusps and fossae. 3. Foils Foils are the thinnest indicator materials which give more accurate readings than paper and silk 4- Occlusal indicator wax It follows a concept like impression materials, where the material is placed on the maxillary arch and the patient occludes in maximum intercuspation 18 Silk strips OCCLUSAL WAX INDICATOR FOIL 19  T-Scan System T-Scan The is a computerized device that consists of: 1) hand-held device with flat U-shaped pressure measuring sensor 2) computer software. 20  Photo-occlusion system It consists of a thin photoplastic film layer which is positioned on the occlusal surface of the teeth in which the patient would bite for ten to twenty seconds. Then the film layer is inspected under a polariscope light to obtain the relative tooth contact intensity was measured. 21  Requirements for Occlusal Stability Maximum intercuspation Light or absent anterior contacts Well-distributed posterior contacts Cross-tooth stabilization Forces directed along long axis of each tooth Smooth excursive movements without interferences No trauma from occlusion Favorable subjective response to occlusal form and function  OCCLUSAL THERAPY The purpose of occlusal therapy is to establish stable functional relationships favorable to the oral health of the patient, including periodontium. Effective nonsurgical therapy usually reduces inflammation within the periodontium and results in some healing of attachment, which often results in mobile teeth becoming more stable. When there is sufficient evidence of excessive occlusal forces on the patient’s teeth or when masticatory system disharmony exists and the patient desires a more stable occlusion, an occlusal appliance is prescribed. 23  Indications for occlusal therapy Trauma from occlusion Bruxism, muscular dysfunction Some forms of TMJ pathosis ,Food impaction Increased tooth mobility Dental pain associated with occlusion Occlusal soft tissue injury OCCLUSAL EQUILIBRATION 1. when there are occlusal contact relationships that cause trauma to the periodontium, joints, muscles or soft tissues. 2. When there are interferences that aggravate parafunction 24  TREATMENT OPTIONS 1. occlusal appliance therapy 2. occlusal adjustment 3. occlusal stability for restorative dentistry 4. orthodontic tooth movement 5. orthognathic therapy 25  Occlusal adjustment Occlusal adjustment or the selective reshaping of the occluding surfaces of the teeth can reduce the magnitude of occlusal interferences or direct the forces to be more compatible with the long axes of the affected teeth. 26 CORONOPLASTY 1. Retrusive prematurity's are eliminated. 2. Adjust ICP to achieve stable, simultaneous contacts 3.Test for excessive occlusal contact on the incisors in ICP 4.Elimination of posterior protrusive contacts. 5.Reduce mediotrusive prematurities 6. Laterotrusive prematurities 7.Gross occlusal disharmonies 8.Recheck Contact relationships. 27  The correction of occlusal supracontacts consists of grooving, spheroiding and pointing. 28  Any questions ?? 29