Angular Dimensions of Retromolar Pad: An Observational Study

Abstract

Background Retromolar pad RMP is at an incline and is relatively resistant to resorption as compared to mandibular residual alveolar ridge due to the attachments of muscles and dense cortical bone underlying it. The existing stock trays are usually flat and cause undue pressure in RMP region often requiring arbitrary modification of stock tray. This study was conducted to record the RMP incline and formulate a stock tray that will help in recording an accurate impression to achieve excellent seal stability and support in the denture base.Methods RMP inclines and the residual ridge crests were marked on 280 master casts using markers and the angle between them were recorded using a protractor kept at the level of eye. Results The angle of RMP with the crest of ridge recorded on right and the left sides ranged between 105deg- 175deg and 125deg-180deg respectively. A p value of 0.024 was obtained with paired sample t-test. The mean angle of left and right sides combined was 152.12 plusmn 13.10deg. After removal of outliers the lower limit was 135deg which can be incorporated in an impression tray to accommodate the critical incline of RMP.Conclusion The present study recorded an angle of 135deg between RMP and residual ridge which can be considered as the standard angle for stock trays. Incorporating an angle of 135deg would be adequate to accommodate higher angles up to 175deg. This enables creating a strong foundation for a good complete denture prosthesis in patients with extremely resorbed mandibular completely edentulous ridges.