The success of dental implants is highly dependent on integration between the implant and intraoral hard/soft tissue. Initial breakdown of the implant-tissue interface generally begins at the crestal region in successfully osseointegrated endosteal implants, regardless of surgical approaches (submerged or nonsubmerged). Early crestal bone loss is often observed after the first year of function, followed by minimal bone loss (≤0.2 mm) annually thereafter. Six plausible etiologic factors are hypothesized, including surgical trauma, occlusal overload, peri-implantitis, microgap, biologic width, and implant crest module. It is the purpose of this article to review and discuss each factor. Based upon currently available literature, the reformation of biologic width around dental implants, microgap if placed at or below the bone crest, occlusal overload, and implant crest module may be the most likely causes of early implant bone loss. Furthermore, it is important to note that other contributing factors, such a...

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The Causes of Early Implant Bone Loss: Myth or Science?

Collagen materials have been utilized in medicine and dentistry because of their proven biocompatability and capability of promoting wound healing. For guided tissue regeneration (GTR) procedures, collagen membranes have been shown to be comparable to non-absorbable membranes with regard to probing depth reduction, clinical attachment gain, and percent of bone fill. Although these membranes are absorbable, collagen membranes have been demonstrated to prevent epithelial down-growth along the root surfaces during the early phase of wound healing. The use of grafting material in combination with collagen membranes seems to improve clinical outcomes for furcation, but not intrabony, defects when compared to the use of membranes alone. Recently, collagen materials have also been applied in guided bone regeneration (GBR) and root coverage procedures with comparable success rates to non-absorbable expanded polytetrafluoroethylene (ePTFE) membranes and conventional subepithelial connective tissue grafts, respectively. Long-term clinical trials are still needed to further evaluate the benefits of collagen membranes in periodontal and peri-implant defects. This article will review the rationale for each indication and its related literature, both in vitro and in vivo studies. The properties that make collagen membranes attractive for use in regenerative therapy will be addressed. In addition, varieties of cross-linking techniques utilized to retard the degradation rate of collagen membranes will be discussed.

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Collagen Membranes: A Review

A clinical trial was undertaken to study the healing capacity of the periodontal tissues following different modes of periodontal surgery in patients whose oral hygiene was professionally maintained at an optimal level. Fifty patients, distributed into five groups, participated in the study. Following an initial examination and presurgical treatment, the various patient groups were subjected to one of the following surgical procedures: 1) the apically repositioned flap operation including elimination of bony defects, 2) the apically repositioned flap operation including curettage of the bony defects but without removal of bone, 3) the “Widman flap” technique including elimination of bony defects, 4) the “Widman flap” technique including curettage of the bony defects but without removal of bone, 5) gingivectomy including curettage of the bony defects but without removal of bone. After surgery, all patients received oral hygiene instruction and professional cleaning of the teeth once every 2 weeks during a 2-year period.

The results showed that periodontal disease can be cured and further destruction of the periodontal tissues avoided irrespective of the surgical technique utilized for pocket elimination. Different surgical techniques, however, promoted varying degrees of regeneration of the supporting tissues. The most favourable healing was obtained when resection of bone was avoided and when complete coverage of the alveolar bone was ensured.

The healing potential of the periodontal tissues following different techniques of periodontal surgery in plaque-free dentitions. A 2-year clinical study.

A piezoelectric instrument vibrating in the ultrasonic frequency range was investigated for its potential use in periodontal resective therapy. The rate of postoperative wound healing (baseline and 14, 28, and 56 days after surgery) in a dog model following surgical ostectomy and osteoplasty was the marker used to compare the efficacy of this instrument (PS) with a commonly used carbide bur (CB) or a diamond bur (DB). The surgical sites treated by CB or DB lost bone, in comparison to baseline measurements, by the 14th day, while the surgical sites treated by PS revealed a gain in the bone level. By day 28, the surgical sites treated by all three instruments demonstrated an increased bone level and regeneration of cementum and periodontal ligament. However, by day 56, the surgical sites treated by CB or DB evidenced a loss of bone, versus a bone gain in the PS-treated sites. Thus, it appears that PS provided more favorable osseous repair and remodeling than CB or DB when surgical ostectomy and osteoplasty procedures were performed. Therefore, PS could be regarded as being efficacious for use in osseous surgery.

Osseous response following resective therapy with piezosurgery.

Background: Thick gingival tissue eases manipulation, maintains vascularity, and promotes wound healing during and after surgery. A few recent case reports correlate greater flap thickness to mean and complete root coverage after mucogingival therapy for recession defects. The aim of this systematic review is to appraise the current literature on this subject and to combine existing data to verify the presence of any association between gingival thickness and root coverage outcomes.Methods: Human studies that reported the number and class of recessions, measured flap thickness at a well-defined location, described the method of root coverage used, followed results for at least 3 months, and detailed mean root coverage underwent review and statistical analysis. Investigations were scored from 1 to 5 based on methodological quality. Weighted gingival thickness and weighted mean root coverage was calculated based on standard error. Statistical analysis used the Mann-Whitney test, analysis of variance (ANOVA)...

Flap thickness as a predictor of root coverage: a systematic review.

OSSEOUS SURGERY PROCEDURES are being performed on the vestibular bone over the tooth root by the profession for correction of alveolar bone deformities resulting from periodontal disease. Various mucoperiosteal flap operations are often used in conjunction with osseous surgery to gain access and visibility to the alveolar bone during the surgery. Osseous surgery correcting bone de­ formities can be classified as osteoectomy or osteo­ plasty. An osteoectomy in periodontal surgery indicates the bone immediately adjacent to the periodontal liga­ ment is removed; an osteoplasty is performed if any of the remaining bone other than bone immediately adja­ cent to the tooth is removed. The two types may be utilized separately or together.

Histogenesis of Repair Following Osseous Surgery

PURPOSE To measure the variations in L*a*b* values of a group of 25 guides and to assess whether shade guides are indeed interchangeable. MATERIALS AND METHODS The L*a*b* values of individual shade tabs were measured with a LabScan(tm) XE scanning spectrocolorimeter (SSC) with a special attachment for reproducibly positioning shade tabs. Each shade guide (Vitapan Classical, Vident) contained 16 shade tabs. Absolute calibration of the SSC was performed with color tiles traceable to NIST. One shade guide was used to determine the reproducibility of the experimental method by measuring and then removing each shade tab of the standard 10 times. This assessed the variations in observed values induced by the measurement method and the geometry of the specimens. The entire sample consisted of 25 shade guides. The tabs of each of the 25 shade guides were read five times in the SSC, without moving the specimen. Measurements and calculations of E, L*, a*, and b* were performed using Universal Software V4.10 (Hunter Associates Laboratory). The mean, standard deviation, and range were determined of the E, L*, a*, and b* values for each one of the 16 shades in the shade guides. Differences in color are expressed as DeltaE in color science. The standard deviation of E (E(sd)) and the range of E (E(r)) for each of the shades were used as a DeltaE value to assess color differences. RESULTS For the reproducibility measurements, the shades had values for E(r) varying from 0.08 to 0.69, and E(sd) between 0.02 and 0.22. This established the detection limit for our method for each of the shades. For the group of 25 shade guides, E(r) varied from 0.75 to 3.05, and E(sd) from 0.22 to 0.54. The difference in value of E(r) obtained from the reproducibility test and the E(r) of the group of 25 guides is significant at p < 0.05. The same was found for E(sd). The largest reproducible E(r) observed was 3.05 for shade C1. CONCLUSIONS The differences observed between shade guides are larger than the variations induced by the experimental method. The difference in E values for the shades C1 and C2 is 2.19; hence the observed E(r) of 3.05 between shade tabs of the same shade (C1) is larger than the changes in color between shades. This large a variation in what are claimed as identical shade tabs is deemed of clinical importance, and therefore, the shade guides should not be considered interchangeable.

Variations of L*a*b* values among Vitapan Classical Shade Guides.

This study compared the effect of payment systems on recall visits and oral health outcomes for four patient payer groups. The authors reviewed recall audit data obtained over a 4-year period. Dental payer groups in the study population differed with respect to dental outcomes. Patients who had recall visits at 1 year or longer had worse outcomes than patients seen more frequently. A Medicaid subgroup with the greatest number of risk factors displayed improved oral health outcomes when seen on a more frequent recall schedule. Study findings suggest that, given the increased risks to maintaining oral health, patients being supported by public-funded programs would benefit from more frequent recalls. Such an emphasis would appear to provide the opportunity to improve outcomes in disadvantaged populations and increase the quality of care offered.

Kenneth A. King

Papers

Histogenesis of Repair Following Osseous Surgery

Variations of Lab* values among Vitapan Classical Shade Guides.

Oral health outcomes in an adult dental population: the impact of payment systems.