Onlay partial denture 嘉泉醫大 吉病院 齒科센터

Anterior teeth – attrition Vertical dimension – decrease RPD - abrasion

A. Etiology Parafunctional occlusal habits Chronic bruxism Other oral habits : biting on needles, pipe stems, pencils, hairpins

A. Etiology Abrasion : diet – chewing of abrasive materials (rice, tabacco) Definition : defined as the wearing away of tooth tissue by external agents Occlusal abrasion is usually attributed to diet, chewing of abrasive. Environment factors : constant exposure to dust and grit

A. Etiology Erosion : chemical action Result from excessive intake citrus juices, cola, chronic vomiting Incisal edge, lingual or occlusal surface : cupped-out appearance (unbalanced occlusal force)

Evaluation of Vertical Dimension OVD : occlusal vertical dimension VDO : vertical dimension of occlusion VDR : vertical dimension of rest

C. Methods of evaluation Posterior support History of wear Phonetic evaluation Inter-occlusal distance Facial appearance

C. Methods of evaluation Posterior support Loss of posterior support is the most common cause of decreased occlusal vertical dimension Posterior collapsar : combination of missing, tipping, rotated and broken down teeth

C. Methods of evaluation Phonetic evaluation : speaking space 를 이용 하는 방법에는 “S” sound 시 하악 전 치의 incisal edge 가 상악 incisal edge 에 비해 1mm 정도 inferior and lingual 에 위 치함, 1mm 이상의 차이가 있을시 VD 의 loss 가 있다고 봄

C. Methods of evaluation Inter-occlusal distance ; VDO, VDR 에서 3mm 이상 차이가 있으면 excessive wer 가 있다고 본다. 재는 방법에 따라 논란 이 많음. 그러나 complete denture 환자 에 있어서 VD 재는 방법을 이용하기도 하 고 myomonitor 를 이용하기도 한다.

Approaching technique OVD 를 변화 시키는 치료를 행 할 때는 다음의 원칙을 준수 해야 한다. Concepts of conservative treatment Trial period with interim prosthesis Transitional RPD (desired OVD) Use of acrylic splint Use of provisional restoration

Interim removable partial denture

Initial patient assessment Intraoral examination Extraoral examination Smile analysis Phonetic evaluation Initial prostheses assessment

Initial patient assessment Intra-oral examination Excessive loss of tooth structure Healthy periodontum with sufficient bone Lack of posterior occlusion Class I jaw relationship

Initial patient assessment Extra-oral examination Slight decrease in facial height Inversion of maxillary lip Inter-occlusal rest space of 3 to 4mm

Initial patient assessment Smile analysis No touch of maxillary teeth to lower lip Straight maxillary incisal edge alignment to lower lip Increase vestibular space

Initial patient assessment Phonetic evaluation F-V position – inadequate in vertival plane S position : acquired “S”sound deficiency

Initial patient assessment Initial prostheses assessment Poor plane of occlusion Lack of occlusion as a result of excessive wear of acrylic resin Inadequate border extensions

To determinate the VD 4mm increase ( anterior incisor area) Direct assessment technique Diagnostic wax-up technique

Mounted diagnostic wax-up To assess the patient’s tolerance & acceptance of restored OVD Use face-bow, centric relation, condylar angle (protrusive record, lateral check bite) Mount the semi-adjustable articulator

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