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ePaper created 2015-03-07, 18:13:20 | version 1.33.01
I case report _ use of CBCT _Introduction _Dental implants have become one of the most predictable treatment alternatives for patients who are missing teeth. Despite the high success rates, whicharewelldocumented,mostdentalimplantsare stillinsertedbyafree-handmethodofdelivery.CTand CBCT and have played an increasingly important role inthediagnosisandtreatmentplanningphase,allow- ingforincreasedaccuracy,predictability,improvedap- preciation of adjacent vital structures, and decreased complications. The use of CBCT imaging and interac- tive treatment planning software allows for the sim- ulation of dental implants and abutments, providing the foundation for the fabrication of surgical guides. Surgical guides derived from CT/CBCT datasets have been classified as tooth-borne, bone-borne, and mu- cosal-borne, and can be fabricated from a variety of methods, including CAD/CAM and stereolithography or 3-D printing of resin material with the incorpora- tion of metal guide tubes. StereolithographicguidesderivedfromCBCTdata and interactive treatment planning software allow for precise placement of implants around vital struc- tures and reduced alveolar support and control for depth, angulation and position.1 While most guides havebeeneithersupportedbyteeth,mucosaorbone, other guides have gained support/stability from mini implants.The2014Consensuspaper(IJOMI)reviewed the literature regarding the accuracy of guided sur- gery for implant placement.2 The Consensus paper found that bone-supported templates had greater deviations than mucosal or mini implant-supported guides and tooth-supported guides were the most accurate. With regard to accuracy, clinical deviations atthepointofdrillentryhavebeenreportedfromless than 1mm to 1.5mm. Errors at the apex have been reportedtobefrom1.5mmto3mm(moredependent on implant length) and angulation errors were re- portedfrom5degreesto8degrees.Withtheseerrors in mind, it would be prudent to plan a safety zone of at least 2mm from adjacent vital anatomical struc- Fig. 1_Pre-op photo showing the three existing Locator abutments. The use of existing locators to stabilize a CBCT-software derived surgical guide Conversion of a mandibular removable to a fixed prosthesis Author_ Dr Barry Kaplan, USA 10 I cone beam1_2015 Fig. 1