International Journal of Periodontics & Restorative Dentistry, 06/2004

The purpose of this study was to examine force transmissions of narrow-diameter ITI implants when used as a terminal support for freestanding three-unit fixed partial dentures (FPD). Photoelastic and strain-gauged models of two 4.1-mm-diameter solid-screw implants; a 3.3-mm reduced-diameter implant and a 4.1-mm-diameter solid-screw implant; and a 3.3-mm-diameter narrow-neck implant and a 4.1-mm-diameter solid-screw implant supporting fixed prostheses were fabricated. A static force of 100 N was applied on both implants and on the pontic of the prostheses in separate load cases, and the generation of isochromatic fringes was observed and photographed in the field of a circular polariscope. The straingauge signals were digitized by a data-acquisition system and displayed in a computer by corresponding software at a sample rate of 10,000 Hz, and the principal strains were calculated. The use of narrow-neck and reduced-diameter implants resulted in an overall increase in stress and strain magnitudes around supporting implants in comparison with support from two standard solid-screw implants. Narrow-diameter ITI implants may be used to support FPDs for patients with low bite forces. In other clinical situations involving narrow-diameter implants, increasing the implant support is crucial to improve the biomechanical outcome of the treatment.

The aim of this report is to describe the superficial-layer split-thickness flap, which provides maximal flap release and mobilization for coronal positioning. The traditional split-thickness flap technique dissects following the contour of the buccal alveolar plate, leaving a periosteal layer on the osseous surface, while the muscular layer remains with the flap. This limits flap mobilization and can lead to flap retraction during healing because of muscle pull from lip and cheek movement. The superficial-layer split-thickness flap technique dissects following the contour of the external surface of the flap, toward the lip or cheek, and separates the epithelium and connective tissue from the underlying muscular and periosteal layers, which remain attached to bone. The advantages of this technique are: (1) the extreme flap release that allows complete, passive flap coverage for virtually all root coverage, ridge preservation, and ridge augmentation procedures; and (2) the absence of muscle pull during healing, which prevents flap retraction and promotes more rapid union of flap margins. Four cases are presented to demonstrate the flap technique and healing advantages.

Controlled clinical trials that evaluate the benefits of adjunctive subantimicrobialdose doxycycline (SDD) with conventional therapy were selected for review. It was deemed important to distinguish between statistically significant and clinically relevant results related to SDD use to help guide clinicians in selecting appropriate therapies. Several investigations demonstrated that SDD prescribed as an adjunct to conventional therapy provides a statistically significant improvement with respect to probing depth reduction, gain of clinical attachment, decreased bleeding on probing, and reduced incidence of disease progression in patients with chronic periodontitis. However, conflicting data were also noted in some studies. Furthermore, it is suggested that the clinical relevance of improvements obtained with SDD beyond those obtained with conventional therapy is debatable. Therefore, clinicians should interpret the data cautiously and differentiate between statistically significant and clinically relevant findings before altering treatment regimens.

The aim of this prospective clinical study was to analyze graft-enhanced soft tissue healing during the initial phases after tooth extraction. Twenty patients in need of tooth extraction (incisors, canines, and premolars) and implant replacement were included. In patients with multiple extractions, one tooth was randomly selected for treatment. After administration of antibiotics, the selected tooth was gently removed. The socket was completely filled with deproteinized bovine bone mineral integrated in a 10% collagen matrix to fill out the space of the alveolus and support the soft tissue. A biopsy punch with a diameter corresponding to the socket orifice was chosen to harvest a free gingival graft of 2- to 3-mm thickness from the palate. The punched graft was carefully sutured to the deepithelialized soft tissue margins of the socket. One week after graft insertion, 64.3% of the mean graft area was fully integrated, 35.6% was fibrinoid, and 0.1% showed necrotic parts. Three and 6 weeks postsurgery, the mean integrated graft surface increased to 92.3% and 99.7%, respectively. After 6 weeks, a mean of 0.3% of the surface in four grafts showed incomplete wound closure, and no fibrin or necrosis was present. Colorimetry of the graft and adjacent tissue revealed a mean color match of ΔE = 2.91, lower than the critical threshold of 3.7 for intraoral visibility of different colors. This soft tissue punch technique led to successful biologic and esthetic integration of the transplanted graft into the local host tissues.

This 6-month clinical study evaluated the use of a porous bone mineral matrix xenograft (Bio-Oss) as an adjunct to a biodegradable barrier membrane (Bio-Gide) to support healing following the immediate placement of transmucosal implants into extraction sockets. Twenty adult patients scheduled for tooth replacement with dental implants were accepted for participation. Following implant placement into the extraction site, subjects were assigned to one of two treatment alternatives for the remaining bone defect around the implant: (1) Bio-Oss + Bio-Gide membrane (test); or (2) Bio-Gide membrane (control). The treatment outcome was evaluated after 6 months by the use of clinical and radiographic variables. The null hypothesis of no treatment group differences was tested by ANOVA. At 6 months, the radiographic bone level remained unchanged compared to baseline in the test and control groups. No differences were observed between test and control groups in terms of mean probing attachment level. At proximal sites, the soft tissue margin was located 2.6 mm more coronal than the shoulder of the implant in the test group, compared to 1.3 mm in the control group. The corresponding figures for the lingual aspect were 2.3 mm and 1.1 mm, respectively, and at buccal sites 2.1 mm and 0.9 mm, respectively. The use of deproteinized bovine bone mineral as a membrane support at immediately placed transmucosal implants may offer an advantage in areas with high esthetic demands in terms of soft tissue support.

Based on a systematic review of the literature from 1986 to 2002, this study sought to determine the survival rate of root-form dental implants placed in the grafted maxillary sinus. Secondary goals were to determine the effects of graft material, implant surface characteristics, and simultaneous versus delayed placement on survival rate. A search of the main electronic databases was performed in addition to a hand search of the most relevant journals. All relevant articles were screened according to specific inclusion criteria. Selected papers were reviewed for data extraction. The search yielded 252 articles applicable to sinus grafts associated with implant treatment. Of these, 39 met the inclusion criteria for qualitative data analysis. Only 3 of the articles were randomized controlled trials. The overall implant survival rate for the 39 included studies was 91.49%. The database included 6,913 implants placed in 2,046 subjects with loaded follow-up time ranging from 12 to 75 months. Implant survival was 87.70% with grafts of 100% autogenous bone, 94.88% when combining autogenous bone with various bone substitutes, and 95.98% with bone grafts consisting of bone substitutes alone. The survival rate for implants having smooth and rough surfaces was 85.64% and 95.98%, respectively. Simultaneous and delayed procedures displayed similar survival rates of 92.17% and 92.93%, respectively. When implants are placed in grafted maxillary sinuses, the performance of rough implants is superior to that of smooth implants. Bone-substitute materials are as effective as autogenous bone when used alone or in combination with autogenous bone. Studies using a split-mouth design with one variable are needed to further validate the findings.

This radiographic study evaluated the efficacy of different concentrations of rhBMP-2 to regenerate bone in alveolar defects in the anterior maxilla. The study was performed using reasonably standardized CT examinations and the Simplant program. The radiographic measurements were further refined by careful standardization of the measured regions of interest. There was a statistically significant difference in bone formation between subjects treated with a concentration of 1.5 mg/mL rhBMP-2 compared with each of the other groups. There was no statistically significant difference in bone volume between any of the other groups. None of the groups showed a loss in bone volume.

The goal of this report is to present a novel treatment strategy for mucogingival defects. The use of platelet concentrate gel in a collagen sponge carrier, combined with a coronally positioned flap procedure, is presented in two cases. Complete root coverage was achieved in both cases. Optimal esthetic results, with excellent soft tissue contour and texture, were observed. The patients were satisfied with the appearance. This technique warrants further investigation.