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ePaper created 2018-05-18, 10:27:03 | version 1.38.0
amalgam root-end filling and a cumulative success rate of 59.0 percent; seven studies using contempo- rary surgical procedures (CRS) with a collective sam- ple size of 610 teeth, employing magnifying loupes, ultrasonic root-end preparation and biocompatible filling materials and a cumulative success rate of 88.1 percent; and nine studies on endodontic microsur- gery (EMS) with a total of 699 teeth using the identi- cal techniques as CRS with the only differences being the use of high-power magnification devices such as microscopes or endoscopes instead of loupes and a cumulative success rate of 93.5 percent. The cumulative success rate of the EMS group was significantly higher than the CRS group, which only employed loupes, and the TRS group, which used no magnification. The EMS group combined stud- ies that employed both the dental microscope and the endoscope. It needs to be mentioned that these studies are comparable as both microscopes and endoscopes provide high-power magnification and illumination and also because the microscope is used for the majority of the steps of the surgical procedure in the studies where an endoscope was used during root-end preparation. The endodontic microsurgery procedures dem- onstrated significantly better cumulative success rates than the studies that only employed loupes when all 16 studies with a total of 1,309 teeth were compared. Seven of 16 studies provided information on the individual tooth type (four for CRS and three for EMS), demonstrating a significant difference in probability of success between the groups for molars. Tsesis et al.29 provided an updated systematic review on endodontic surgery in 2013 and also confirmed a statistically significant difference in successful out- comes of both microscope and endoscope-assisted procedures compared with loupes. _Microscope features and upgrades Modern dental microscopes have evolved consid- erably with regard to features and options available to the dental clinician. Depending on personal prefer- ences and possible locations in the operatory, floor- standing, wall- or ceiling-mounted units are avail- able. While standard microscopes come with basic optics and light options, certain accessory features are recommended for endodontic purposes. Surgical procedures will require greater angulations to view resected root surfaces and other surgical details. At a minimum, a microscope should be equipped with 180-degree-tiltable binoculars to address the angu- lation requirements and an eyepiece with a reticle. A reticle is a set of fine lines, most commonly in the shape of crosshairs or concentric rings, that provides proper centering on the object in focus and allows for easier individual calibration (parfocaling) of the C.E. article_ microscopes I Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 microscope. It also is an indispensable tool for docu- mentation. Since light and the object image reach the binoculars virtually free of shadows, microscope photography and recording allow for excellent image quality for documentation and clinical operations. However, this requires perfect calibration with an external monitor and a reticle to center the image. Full high-definition and three-chip cameras are the gold standard for video recording and available as ex- ternal or internal solutions. Screenshots from video recordings can be obtained at higher quality by using post-processing software applications that allow for image stacking.30 For still photography, new genera- tion digital mirrorless cameras have demonstrated advantages compared with DSLRs. There is a variety of additional upgrades for core microscope functions. Instead of fixed focal distances that limit the microscope to an object dis- tance of 200 mm, 250 mm or 300 mm, variable focal distance adapters have become available, allowing for easier switching between practitioners and easier adjustment to patients of different statures. These are offered in top-of-the-line microscopes, often in conjunction with electrical zoom and fine focus op- tions that allow smooth and stepless adjustments of both magnification and focus. Extendable (foldable) Fig. 7_Pre-op image of a mandibular right first molar in which nonsurgical root canal treatment had been completed five years ago. (Photos/ Provided by Dr. Frank C. Setzer) Fig. 8_Clinical image shows previously treated canals with infected gutta-percha filling. Fig. 9_A furcation canal is visible under high magnification (arrow). Fig. 10_A third distal canal is also located under magnification. Fig. 11_Post-operative radiograph shows the retreated tooth with five main canals. Fig. 12_The one-year follow-up radiograph demonstrates the complete resolution of the periradicular radiolucencies and permanent restoration of the tooth. roots 1_ 2018 I 09