Richard D. Trushkowsky

Effect of Interimplant Distance (2 and 3 mm) on the Height of Interimplant Bone Crest: A Histomorphometric Evaluation

BACKGROUND Implants restored according to a platform-switching concept (implant abutment interface with a reduced diameter relative to the implant platform diameter) present less crestal bone loss than implants restored with a standard protocol. When implants are placed adjacent to one another, this bone loss may combine through overlapping, thereby causing loss of the interproximal height of bone and papilla. The present study compares the effects of two interimplant distances (2 and 3 mm) on bone maintenance when bone-level implants with platform-switching are used. METHODS This study evaluates marginal bone level preservation and soft tissue quality around a bone-level implant after 2 months of healing in minipig mandibles. The primary objective is to evaluate histologically and histomorphometrically the affect that an implant design with a horizontally displaced implant-abutment junction has on the height of the crest of bone, between adjacent implants separated by two different distances. RESULTS Results show that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for interimplant distances of 2 or 3 mm. The horizontal position of the bone relative to the microgap on platform level (horizontal component of crestal bone loss) was 0.31 ± 0.3 mm for the 2-mm interimplant distance and 0.57 ± 0.51 mm above the platform 8 weeks after implantation for the 3-mm interimplant distance. CONCLUSIONS This study shows that interimplant bone levels can be maintained at similar levels for 2- and 3-mm distances. The horizontally displaced implant-abutment junction provided for a more coronal position of the first point of bone-implant contact. The study reveals a smaller horizontal component at the crest of bone than has been reported for non-horizontally displaced implant-abutment junctions.

Treatment of dentin hypersensitivity.

Dentinal hypersensitivity is exemplified by brief, sharp, well-localized pain in response to thermal, evaporative, tactile, osmotic, or chemical stimuli that cannot be ascribed to any other form of dental defect or pathology. Pulpal pain is usually more prolonged, dull, aching, and poorly localized and lasts longer than the applied stimulus. Up to 30% of adults have dentinal hypersensitivity at some time. Current techniques for treatment may be only transient in nature and results are not always predictable. Two methods of treatment of dentin hypersensitivity are tubular occlusion and blockage of nerve activity. A differential diagnosis needs to be accomplished before any treatment.

Radiological and micro‐computed tomography analysis of the bone at dental implants inserted 2, 3 and 4 mm apart in a minipig model with platform switching incorporated

BACKGROUND The purpose of this study was to assess the effect of inter-implant distance on interproximal bone utilizing platform switching. Analysis of interproximal bone usually depends on traditional two-dimensional radiographic assessment. Although there has been increased reliability of current techniques, there has been an inability to track bone level changes over time and in three dimensions. Micro-CT has provided three-dimensional imaging that can be used in conjunction with traditional two-dimensional radiographic techniques. METHODS This study was performed on 24 female minipigs. Twelve animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 2 mm apart creating a split mouth design. Twelve other animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 4 mm apart creating a split mouth design too. The quantitative evaluation was performed comparatively on radiographs taken at t 0 (immediately after implantation) and at t 8 weeks (after termination). The samples were scanned by micro-computed tomography (μCT) to quantify the first bone to implant contact (fBIC) and bone volume/total volume (BV/TV). Mixed model regressions using the nonparametric Brunner-Langer method were used to determine the effect of inter-implant distance on the measured outcomes. RESULTS The change in bone level was determined using radiography and its mean was 0.05 mm for an inter-implant distance of 3 and 0.00 mm for a 2 mm distance (P = 0.7268). The mean of this outcome was 0.18 mm for the 3 mm and for 4 mm inter-implant distance (P = 0.9500). Micro-computed tomography showed that the fBIC was always located above the reference, 0.27 and 0.20 mm for the comparison of 2-3 mm (P = 0.4622) and 0.49 and 0.34 mm for the inter-implant distance of 3 and 4 mm (P = 0.1699). BV/TV inside the defined parallelepipedic masks reached 82.38% for the 2 mm inter-implant distance and 85.00% for 3 mm, P = 0.8432. For the comparison of the 3-4 mm inter-implant distance, the means were 84.69% and 84.38%, respectively, P = 0.8401. Non-inferiority tests for the smaller inter-implant distances for both comparisons showed similar differences and similar tolerance ranges. CONCLUSION The effect of a smaller interproximal distances between implants on bone level, fBIC and BV/TV assessed by two convergent investigation methods, radiology and μCT, was similar to that of larger distances. Implants can potentially be placed 2 mm apart instead of 3 mm and 3 mm apart instead of 4 mm when platform switching is utilized. Further research with a conventional platform is warranted.

Esthetic and Functional Consideration in Restoring Endodontically Treated Teeth

The selection of the best restoration for an endodontically treated tooth in the aesthetic zone depends on strength and the ability to recreate the form, function, and aesthetics of the natural tooth. The increased use of all-ceramic materials is a result of improved ceramic materials and adhesive systems. However, the advent of the current variety of translucent ceramic systems makes the shade of the abutment important in achieving the desired aesthetic outcome. This article discusses the different types of posts used in the restoration.

Treatment of the Patient with Gummy Smile in Conjunction with Digital Smile Approach.

Gummy smile cases are always esthetically demanding cases. This article presents a case treated with an interdisciplinary treatment approach and Digital Smile Approach (DSA) using Keynote (DSA), to predictably achieve an esthetic outcome for a patient with gummy smile. The importance of using questionnaires and checklists to facilitate the gathering of diagnostic data cannot be overemphasized. The acquired data must then be transferred to the design of the final restorations. The use of digital smile design has emerged as a powerful tool in cosmetic dentistry to help both practitioner and patient visualize the final outcome.

Effect of 3- and 4-mm interimplant distances on the height of interimplant bone crest: a histomorphometric evaluation measured on bone level dental implants in minipig.

Purpose: To analyze crestal bone loss changes that may affect the gingival height around an implant and bone loss in interproximal areas. When implants are placed adjacent to one another, interimplant bone loss around 1 implant may combine with the implant bone loss around the adjacent implant to affect the crestal bone loss interproximally. Materials and Methods: The primary objective of this study was to evaluate histologically and histomorphometrically the effect that this implant design with a horizontally displaced implant-abutment junction has on the height of the crest of bone, between adjacent implants separated by 2 different distances: 4 mm and 3 mm. A secondary objective was to evaluate the percentage of bone-to-implant contact, interproximal soft tissue height, location of the junctional epithelium, and length of connective tissue contact to abutment and/or implant, for the 2 different distances. Results: Results showed that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for interimplant distances of 4 or 3 mm. In addition, the secondary objective parameters also demonstrated similar results between the 2 interimplant distances. Conclusion: This study showed that interimplant bone levels can usually be maintained at similar levels for 4- and 3-mm distances during at least 2 months.

Interfaces in fixed dental prostheses: Challenges and opportunities

In recent years, zirconia-based restorative systems (i.e., porcelain-veneered zirconia and monolithic zirconia) have emerged as promising materials for all-ceramic prostheses due primarily to their superior mechanical properties, esthetics, and biocompatibility. However, the susceptibility to porcelain fracture as well as the poor fusion and resin–cement bonding capability of zirconia prevent the widespread use of such material systems. We have developed a surface glass infiltration method that creates a functionally graded material layer at the bonding surfaces of zirconia. Our test data show that glass infiltration at the veneering surface can effectively prevent veneer chipping and delamination, whereas that at the cementation surface can increase the interfacial fracture energy of zirconia by over a factor of 3, to a level consistent with feldspathic ceramic. These qualities, together with the increased resistance to flexural and contact damage, edge chipping, and delamination found in previous studies, suggest that functionally graded zirconia can be considered as a viable material option for dental restorations.

Tissue Healing Around Dental Implants With Marginal Bone Defects With and Without Flap Elevation: An Experimental Study in Dogs

The technique of immediate implant placement after extraction has been conceived for preserving residual bone support and soft tissue morphology. Today, this procedure is still unpredictable and presents inconveniences for both the patient and the dentist. Therefore, the healing process around a dental implant placed into an extraction socket needs to be deeply investigated to increase the predictability of this surgical approach. The aim of the present investigation was to evaluate the healing of bone defects (fresh extraction sockets) after implant installation with flap elevation, and primary closure compared with implant installation without flap elevation. This study use histologic and histomorphometric analyses to evaluate tissue healing around dental implants with marginal bone defects with and without flap elevation 1 week, 4 weeks, and 12 weeks after implantation in the dogs. The main qualitative findings showed that after 1 week of implantation almost no bone repair was observed, and there was no significant difference between the 2 groups in terms of bone-healing performance, inflammatory infiltrates (slight to moderate grade), and bone resorption (moderate to marked grade) limited to the coronal portion of the implanted sites. The 2 groups with or without flap elevation behaved similarly at this point of implantation. Under the experimental conditions of this study, no biological differences were observed between the 2 groups with and without flap elevation in terms of crestal bone repair, inflammation, marginal bone loss, and soft tissue downgrowth. The qualitative differences observed might be imputable to fortuitous events. The histomorphometric measurements confirmed the qualitative trends observed. The limitations of this study, as with all animal studies, are its translational aspects. Investigation of the same topic in a human population by setting up a controlled, randomized, prospective trial including a sufficient amount of patients investigated according to the split-mouth method would be beneficial.

The Interplay of Orthodontics, Periodontics, and Restorative Dentistry to Achieve Aesthetic and Functional Success

Previously dentists focused on repair and maintenance of function. However, the emphasis of many patients and dentists is now on esthetics. Often there is a need for the disciplines of orthodontics, periodontics, restorative dentistry, and maxillofacial surgery to work together in order to achieve optimum results. Currently the sequencing planning process begins with esthetics and then function, structure, and ultimately biology.

Modern Concepts in Aesthetic Dentistry and Multidisciplined Reconstructive Grand Rounds

In April 2007, Elsevier published an issue of Dental Clinics of North America entitled “Successful Esthetic and Cosmetic Dentistry for the Modern Dental Practice.” Authors and topics were selected that would provide generalists, specialists, seasoned practitioners, and recent graduates with foundational knowledge in a clear and concise text to help them provide their patients with those often elective procedures requested in the modern-day practice of dentistry. In April 2011, with our next project, entitled “Esthetic and Cosmetic Dentistry for Modern Dental Practice: Update 2011,” we continued to provide the readership with updated information on additional foundational material not covered in the previous issue. We also provided adjuncts for patient evaluation and improved communicative skills that would allow for better diagnosis, better treatment planning, better case presentation, and better laboratory communication. In this, our third project for Dental Clinics of North America, entitled “Modern Concepts in Aesthetic Dentistry and Multidisciplined Reconstructive Grand Rounds,” we have again provided foundational knowledge on adjuncts that will help clinicians provide quality, long-lasting restorations for their patients. In addition to this continued evidence-based information—including an updated Smile Evaluation Form, the use of the Kois analyzer, and Dr Ward’s proportional smile design—this issue champions “the medical model,” presenting numerous cases that apply all of our previous preparation with the intent of bringing our readers’ clinical knowledge to new heights. These cases furnish not only the functional and physiologic requirements of treatment planning but also the aesthetic component that is often considered a key component of excellence in modern dental care. They each offer pearls of information that in our opinion can be immediately incorporated into the practices of readers.