Dennis P. Tarnow

Gingival Zenith Positions and Levels of the Maxillary Anterior Dentition

PURPOSE The location of the gingival zenith in a medial-lateral position relative to the vertical tooth axis of the maxillary anterior teeth remains to be clearly defined. In addition, the apex of the free gingival margin of the lateral incisor teeth relative to the gingival zeniths of the adjacent proximal teeth remains undetermined. Therefore, this investigation evaluated two clinical parameters: (1) the gingival zenith position (GZP) from the vertical bisected midline (VBM) along the long axis of each individual maxillary anterior tooth; and (2) the gingival zenith level (GZL) of the lateral incisors in an apical-coronal direction relative to the gingival line joining the tangents of the GZP of the adjacent central incisor and canine teeth under healthy conditions. MATERIALS AND METHODS A total of 240 sites in 20 healthy patients (13 females, 7 males) with an average age of 27.7 years were evaluated. The inclusion patient criteria were absence of periodontal disease, gingival recession, or gingival hypertrophy as well as teeth without loss of interdental papillae, spacing, crowding, existing restorations, and incisal attrition. GZP dimensions were measured with calibrated digital calipers for each individual tooth and within each tooth group in a medial-lateral direction from the VBM. GZLs were measured in an apical-coronal direction from a tangent line drawn on the diagnostic casts from the GZPs of the adjacent teeth. RESULTS This study demonstrated that all central incisors displayed a distal GZP from the VBM, with a mean average of 1 mm. Lateral incisors showed a deviation of the gingival zenith by a mean of 0.4 mm. In 97.5% of the canine population, the GZP was centralized along the long axis of the canine. The mean distance of the contour of the gingival margin in an apical-coronal direction of the lateral incisors (GZL) relative to gingival line joining the tangent of the adjacent central and canine GZPs was approximately 1 mm. CONCLUSION This investigation revealed a GZP mean value of 1 mm distal from the VBM for the central incisor tooth group. The lateral incisors showed a mean average of 0.4 mm. The canine tooth group demonstrated almost no deviations of the GZP from the VBM. The GZL of the lateral incisors relative to the adjacent central incisor and canine teeth were more coronal by approximately 1 mm. These data could be used as reference points during esthetic anterior oral rehabilitation. CLINICAL SIGNIFICANCE The information presented in this article can be clinically applied to reestablish the proper intratooth GZPs of the maxillary anterior teeth during periodontal crown lengthening or root coverage procedures. In addition, the intra-arch gingival level of the lateral incisor gingival zenith relative to the adjacent central and canine teeth can be appropriately established.

Screw loosening for standard and wide diameter implants in partially edentulous cases: 3- to 7-year longitudinal data.

Screw loosening is considered to be a common problem with both screw - retained and cemented implant restorations. A wider abutment platform, as well as using a torque driver to tighten specifically designed screws may help prevent this loosening. However, there has been no clinical study evaluating either of these. To longitudinally compare the frequency of screw loosening in standard diameter, (3.75 and 4.0 mm) implant supported prostheses to that of wide diameter, (5.0 and 6.0 mm) implant supported prostheses that were hand tightened, and to evaluate whether using a torque driver would minimize or prevent this problem, if screw loosening occurred. A total of 213 dental implants in 106 patients were included in this prospective longitudinal study. Of the implants 68 were wide diameter and 145 were standard diameter implants. Wide diameter implants showed 5.8% screw loosening, while standard diameter implants showed 14.5% screw loosening after insertion with only hand torquing. When these loose screws were tightened with a torque driver, there was no more loosening of screws. Within the limitations of this study, the wide diameter implants tested showed less screw loosening than the standard diameter implants when hand torqued. Additionally, within the scope of our study, using a torque driver to tighten the screws with the recommended force prevented this loosening from reoccurring in all cases.

Survival Rate of Immediately vs Delayed Loaded Implants: Analysis of the Current Literature

Immediate loading of oral implants has been reported as a beneficial treatment protocol in implant dentistry that increases the comfort of the patient. However, documentation in the literature is poor regarding the clinical outcome and the peri-implant bone response of immediately loaded implants compared with the conventional loading protocol placed in different bone qualities. The aim of this report was to present the role of bone quality in the survival rate of implants using conventional or immediate loading according to the literature. A literature search analysis was performed to demonstrate the survival rate of immediately loaded implants, as well as data from the histologic and histomorphometric evaluation in comparison with conventional loaded implants. This analysis showed high survival rates of immediately loaded implants along with osseointegration, with high percentages of bone-to-implant contacts based on histologic evaluation from human and animal studies of immediately and conventionally loaded implants. This study may provide histologic and clinical evidence of the immediate loading protocol for different bone qualities.

Extraction Sockets and Implantation of Hydroxyapatites With Membrane Barriers A Histologic Study

The purpose of this pilot study was to investigate the effect on extraction socket healing when an absorbable hydroxyapatite (AH) and a nonabsorbable anorganic bovine bone mineral (ABB) covered with either an acellular dermal matrix allograft (ADMA) or expanded polytetrafluoroethylene (ePTFE) membrane barrier were left exposed to the oral cavity. Following tooth extraction, a total of 16 sockets in 15 patients with deficient buccal plates of ≥5 mm were randomly divided into 4 treatment groups: 1) AH covered with ADMA, 2) AH covered with an ePTFE membrane, 3) ABB covered with ADMA, and 4) ABB covered with an ePTFE membrane. Primary coverage was not attempted or obtained in any of the 16 treated sockets. Six to 8 months postextraction at the time of implant placement, histologic cores of the treatment sites were obtained. These cores were processed, stained with Stevenel’s blue/van Gieson’s picro fuchsin, and histomorphometrically analyzed. Vital bone, connective tissue and marrow, and residual graft particles were reported as a percentage of the total core. The mean vital bone was 34.5% (AH with ADMA), 41.7% (ABB with ADMA), 27.6% (ePTFE and AH), and 17.8% (ePTFE and ABB). The average percentage of vital bone in the 8 sockets covered with ADAMA was 38% compared with an average percentage vital bone of 22% in the 8 sockets covered with ePTFE membrane barriers. Because of the small number of specimens in the 4 groups, statistical analysis was not possible. However, in this pilot study, ADMA-covered sites resulted in more vital bone present 6 to 8 months postsocket treatment than obtained in the ePTFE-covered sites regardless of bone replacement materials used. Further research is warranted to see if these results show a similar difference in bone-to-implant contact after implant placement.

Maxillary sinus elevation by lateral window approach : evolution of technology and technique

CONTEXT The maxillary sinus elevation procedure has become an important pre-prosthetic surgical procedure for the creation of bone volume in the edentulous posterior maxilla for the placement of dental implants. Research and clinical experience over the past 30 years has increased the predictability of this procedure as well as reduced patient morbidity. EVIDENCE ACQUISITION Data on grafting materials and implant survival rates comes from 10 published evidence-based reviews that include all relevant published data from 1980 to 2012. Supporting clinical material comes from the experience of the authors. EVIDENCE SYNTHESIS The evidence-based reviews report and compare the implant survival rates utilizing various grafting materials, implant surfaces, and the use or non-use of barrier membranes over the lateral window. Clinical studies report on complication rates utilizing piezoelectric surgery and compare them to complication rates with rotary instrumentation. CONCLUSIONS The conclusions of all the evidence-based reviews indicate that the utilization of bone replacement grafts, rough-surfaced implants, and barrier membranes result in the most positive outcomes when considering implant survival. Further, the utilization of piezoelectric surgery, rather than rotary diamond burs, for lateral window preparation and membrane separation leads to a dramatic reduction in the occurrence of the intraoperative complications of bleeding and membrane perforation.

The use of CO(2) laser in the treatment of peri-implantitis.

Different techniques have been used for the treatment of peri-implant defects. However, there are always questions about the issue of reosseointegration. The present paper explores the recent literature on the topic of peri-implantitis therapy, and presents a surgical protocol for implant surface decontamination using the CO(2) laser, grafting of the defect, and coverage with a membrane according to a clinical case. The results appear to be promising and may improve the long-term clinical outcomes of failing dental implants.

Human Histologic Evidence of Integration of Functionally Loaded Hydroxyapatite-coated Implants Placed Simultaneously with Sinus Augmentation: A Case Report 2½ Years Postplacement

This article histologically and clinically presents a case report showing two retrieved implants that were placed simultaneously at the time of the antral augmentation. These implants were retrieved 2.5 years after placement and 2 years after loading. To our knowledge, this is the first human histological case report of implants that were simultaneously placed with a sinus lift and loaded.

Flapless postextraction socket implant placement in the esthetic zone: part 1. The effect of bone grafting and/or provisional restoration on facial-palatal ridge dimensional change-a retrospective cohort study.

A number of human comparison studies and case series have demonstrated the effectiveness of using a platform-switched implant-to-abutment connection to prevent peri-implant bone loss and subsequent soft tissue loss. To compare the bone around platform-switched and nonplatform-switched connections, adjacent pairs of both connection types were placed in a one-stage surgical procedure on each side of the mandibles of three monkeys (Macaca fascicularis). Eight weeks after abutment connection, histomorphometric analysis showed that both vertical and horizontal alveolar bone resorption had occurred around the nonplatform-switched implants, whereas bone was maintained vertically and new bone formed horizontally around the platform-switched implants.The dental literature has reported vertical soft tissue changes that can occur with immediate implant placement, bone grafting, and provisional restoration ranging from a gain or loss of 1.0 mm. However, little is known of the effects of facial-palatal collapse of the ridge due to these clinical procedures. Based upon treatment modalities rendered, an ensuing contour change can occur with significant negative esthetic consequences. The results of a retrospective clinical cohort study evaluating the change in horizontal ridge dimension associated with implant placement in anterior postextraction sockets are presented for four treatment groups: (1) group no BGPR = no bone graft and no provisional restoration; (2) group PR = no bone graft, provisional restoration; (3) group BG = bone graft, no provisional restoration; and (4) group BGPR = bone graft, provisional restoration. Bone grafting at the time of implant placement into the gap in combination with a contoured healing abutment or a provisional restoration resulted in the smallest amount of ridge contour change. Therefore, it is recommended to place a bone graft and contoured healing abutment or provisional restoration at the time of flapless postextraction socket implant placement.

Implant Periapical Lesions: Etiology and Treatment Options

Implant failures due to apical pathology are conditions that have not been extensively studied nor reported in the literature. The implant periapical lesion (IPAL) has different symptoms, and several etiologies have been proposed in the literature. This article reviews cases of IPAL reported in peer-reviewed journals and presents possible treatment options. Analysis of the data collected was performed based on diagnosis, cause of extraction of the natural tooth, location, period of implant placement, implant surface, and treatment approach. Even the data presented in this review are based on few reported cases the etiology of these lesions seems to be multifactorial or with an unknown origin. Contamination of the implant surface, bone overheating during surgery, excessive torquing of the implant, poor bone quality, perforation or thinning of the cortical bone, premature or excessive load over the fixture, fracture of the bone inside the hollow portion of the hollow implant, and an implant placement in an infected maxillary sinus have been discussed. In general, areas around endodontically compromised teeth should be carefully analyzed prior to implant placement to prevent implant failures.

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.