International Journal of Periodontics & Restorative Dentistry, 02/2007

The present paper reports on two patients who underwent three-dimensional ridge augmentation using a xenograft in combination with recombinant human platelet-derived growth factor-BB (rhPDGF-BB). Patient 1 received a deproteinized bovine block infused with PDGF and secured to the alveolar crest by two fixation screws to augment the crest horizontally. After 5 months, implants were successfully placed. Patient 2 underwent a vertical ridge augmentation procedure that combined deproteinized bovine bone particles embedded in a collagen matrix soaked in PDGF. Three titanium dental implants were placed in each patient 5 months later. Clinical and histologic results showed excellent soft and hard tissue healing. Bone had regenerated throughout the whole area and the xenograft particles were embedded in bone, which presented resorption lacunae close to areas with ongoing bone formation. This indicated that, in augmented areas, intense physiologic remodeling was ongoing. No data exist concerning three-dimensional bone augmentation using PDGF and a xenograft in humans. This report suggests that the use of rhPDGF-BB in combination with a deproteinized bovine graft may have the potential to regenerate large three-dimensional alveolar defects in humans.

This article describes a procedure to achieve natural-looking morphology and surface textures in anterior ceramic restorations. The natural dentition serves as an atlas to interpret and mimic the orientation and location of dental anatomic structures. Transition angles and ridges; proximal slopes; labial grooves; the cervical, middle, and incisal thirds of the buccal surface; the lingual central concavity; and the lingual transition ridges should all be mimicked by the prosthetic work to achieve esthetic integration. The position of buccal transition ridges directly influences the buccal mesiodistal dimension-the so-called "visual width." Once the desired morphology is obtained, a gold powder is used to outline its surface texture. This uniform golden appearance allows for precise identification of specific surface features such as ridges, grooves, and sulci for their consequent mimicking onto the ceramic surface. Specific surface texture characteristics reflect light and thus enhance visual dimensions of the rehabilitation and its final esthetic integration.

Grafting with intraoral bone blocks is a good way to reconstruct severe horizontal and vertical bone resorption in future implant sites. The Piezosurgery System (Mectron) creates an effective osteotomy with minimal or no trauma to soft tissue, in contrast to conventional surgical burs or saws. In addition, piezoelectric surgery produces less vibration and noise because it uses microvibration, in contrast to the macrovibration and extreme noise that occur with a surgical saw or bur. Microvibration and reduced noise minimize a patient's psychologic stress and fear during osteotomy under local anesthesia. The purpose of this article is to describe the harvesting of intraoral bone blocks using the piezoelectric surgery device.

This article describes an alternative surgical approach to the harvesting of subepithelial connective tissue grafts from thin palates. A partial-thickness flap is raised, and a graft composed of epithelium and connective tissue is removed from the palate. The superficial layer (epithelium and a thin zone of connective tissue) is then dissected from the graft and replaced at the donor site to facilitate faster healing. The subjacent layer of connective tissue is placed as needed to obtain root coverage. The clinical application of this technique is described in two patients with multiple gingival recessions.

Computer-driven implant dentistry uses the latest technology to coordinate every aspect of implant treatment. It provides a means with which to control the placement of implants with a high degree of accuracy. This is important, since accuracy has a direct bearing on the safety, esthetics, invasiveness, and cost of implant treatment. Computer-driven implant dentistry must be conceived as a chain in which every link is related to the others. Within this chain, there are elements that can be employed to maximize the benefits realized by computer-guided implant dentistry. A scan template is a radiologic template that permits visualization of the prosthetic plan prior to treatment and determines the course of implant treatment from the perspective of esthetics. The SimPlant software program (Materialise) allows implants to be planned in two and three dimensions using data received from a computerized tomographic scan. The resulting implant plan can be transferred to the mouth and implemented by means of a stereolithographic surgical guide (SurgiGuide, Materialise). Finally, the SAFE System (Materialise) is used for guided implant placement. It is associated with dedicated drilling devices and can be used in combination with SurgiGuides or with traditional acrylic resin guides manufactured by the dental lab on a synthetic plaster cast.

The purpose of this study was to evaluate the new bone formation and biodegradability of various bone fillers placed underneath a nonresorbable membrane (expanded polytetrafluoroethylene [e-PTFE]) in standardized defects in a beagle dog model. Mandibular premolars and first molars were extracted bilaterally in six adult female beagle dogs. Three months after the extractions, six rectangular defects (4 mm apicocoronally, 7 mm mesiodistally, and the entire width of the ridge buccolingually) were surgically created in the alveolar processes. All defects were covered with an e-PTFE membrane and stabilized buccally with stainless steel fixation screws. Five different bone fillers were placed under the membranes in a random configuration in each dog: autogenous bone, demineralized freeze-dried bone, anorganic bovine bone, tricalcium phosphate granules, and collagen sponge. One site in each animal was treated with the e-PTFE membrane alone. Following an 8-month healing period, a bone core was harvested from each grafted site using a trephine drill. Samples from each of the grafted sites were evaluated histologically and histometrically for their bone regenerative potential. The result of this study demonstrated a positive effect of bone fillers on bone regeneration when combined with a nonresorbable membrane; however, no significant differences were found between the various bone fillers in terms of their regenerative potential.

The application of immediate loading of implants in the edentulous maxilla in multiple-risk patients is presented. Five partially edentulous patients attended with failing prostheses supported by hopeless teeth. An immediate-loading protocol was proposed because the patients rejected provisionalization with a removable prosthesis. Multiple teeth were extracted, and 44 immediately loaded implants were placed, most of them (55.5% to 88.9%) in fresh extraction sites, to support a cross-arch prosthesis that was loaded 3 to 4 days after surgery. The overall implant failure rate was 13.4%; in healed sites it was 20% (2/10) and in fresh extraction sites it was 8.82% (3/34). Prosthetic success was 100%. The overall failure rate was higher than is usually seen with the standard delayed-loading approach. Nevertheless, this immediate-loading protocol was satisfactory for the patients and the practitioner because prosthetic success was maintained during the provisionalization phase.

The goal of this study was to evaluate the clinical changes obtained when intrabony defects were treated with an enamel matrix derivative (EMD), a bone graft, and guided tissue regeneration. Fifty patients with a periodontal defect not associated with a furcation and with an attachment loss of at least 7.0 mm were included in this study. Full-thickness flaps were reflected, the roots were planed, EMD was applied, a demineralized freeze-dried bone allograft combined with EMD was placed, a bioabsorbable membrane was placed, and more EMD was applied. The defect areas were then sutured. At a mean of 5.3 months after treatment, there was a mean increase in recession of 0.7 mm, a mean reduction in probing depth of 5.7 mm, and a mean gain in attachment level of 5.0 mm. In this study there was more recession in smokers than in nonsmokers and in defects associated with anterior teeth. Additionally, the deeper defects (those with greater probing depths and attachment level loss) had the greatest reductions in probing depth and gains in attachment level. Based on this study, this technique proved itself to be an effective method to improve the clinical situation when treating periodontal defects not involving furcations.

Correct occlusal relationships are part of the successful prosthetic treatment of edentulous patients. Occlusal checking should be performed via a remount procedure because denture base materials and fabrication procedures cannot provide dimensionally accurate complete dentures. Occlusal errors caused by the adjustment of denture bases to the denture foundation after a certain period of wearing can also be corrected by means of remounting. The following remount procedures for complete dentures are described: fabrication of transfer casts, transfer of a maxillary denture with a facebow, centric relation record, and mounting of dentures with transfer casts in an articulator with a dental stone. Deflective occlusal contacts of denture teeth in centric occlusion can be eliminated by selective grinding and by tooth-guided excursive movements. In complete denture treatment, priority is given to anterior/canine-guided occlusion.