Sharon C. Siegel

Thermal Safety of Er:YAG and Er,Cr:YSGG Lasers in Hard Tissue Removal

OBJECTIVE The aim of this study was to compare the thermal safety of Er:YAG and Er,Cr:YSGG lasers with conventional multi-use and single-use diamond burs. BACKGROUND DATA Thermal effect of tooth preparation is mostly evaluated through the pulp chamber because it is difficult to measure the temperature of the preparation surface. A new in vitro method was introduced to simultaneously evaluate the heat increase of the preparation surface together with the pulp chamber. METHODS Six laser and bur instrument groups were used to make standardized preparations on buccal surfaces of 60 intact third molars. The preparations removed an equal volume of hard tissue from each tooth (4 mm occluso-gingival x 8 mm mesial-distal x 1.6 mm bucco-lingual). The teeth also included tunnel preparations from the opposite (lingual) surface, exposing the pulpal axial wall (axial dentin wall in contact with the pulp chamber from the preparation surface site). An infrared thermal camera was positioned to capture the preparation surface in direct vision, while the pulpal axial wall was indirectly reflected to the thermal camera via a minimal-energy-loss mirror. Data from both surfaces were analyzed statistically using Nested Least Squares Analysis. RESULTS The laser groups generated significantly lower heat compared to bur groups on the preparation surfaces. In contrast, both lasers generated greater pulpal heat increase, and the Er:YAG laser group showed significance (p < 0.0001). CONCLUSIONS Lasers produced less heat on the preparation surface but more on the pulpal axial wall. However the temperature rise was less than the 5.5 degrees C threshold margin of safety.

Simplified Technique for Incorporating a Metal Mesh into Record Bases for Mandibular Implant Overdentures

Mandibular implant-retained overdentures have become the standard of care for patients with mandibular complete edentulism. As part of the treatment, the mandibular implant-retained overdenture may require a metal mesh framework to be incorporated to strengthen the denture and avoid fracture of the prosthesis. Integrating the metal mesh framework as part of the acrylic record base and wax occlusion rim before the jaw relation procedure will avoid the distortion of the record base and will minimize the chances of processing errors. A simplified method to incorporate the mesh into the record base and occlusion rim is presented in this technique article.

Modern Day Treatment Planning Dilemmas; Natural Tooth Versus Implants

Decision-making about a treatment plan whether to preserve a compromised tooth with endodontic therapy and a protective, functional restoration or to extract and replace it with an implant requires evidence-based diagnosis and recommendations based on patient factors, tooth and periodontium-based factors, and treatment-based factors. The first consideration should be the preservation of the natural dentition as long as possible, since the extraction and implant placement can be done at anytime and the implant treatment is not without risk. This component of the chapter outlines the evidence to recommend and plan the most appropriate treatment when faced with restoring the compromised tooth.