International Journal of Periodontics & Restorative Dentistry, 05/2009

The Class III defect environment entails a vertical and horizontal deficiency in the edentulous ridge. Often, bone and soft tissue surgical procedures fall short of achieving a natural esthetic result. Alternative surgical and restorative protocols for these types of prosthetic gingival restorations are presented in this three-part series, which highlights the diagnostic and treatment aspects as well as the lab and maintenance challenges. A complete philosophical approach involves both a biologic understanding of the limitations of the hard and soft tissue healing process as well as that of multiple adjacent implants in the esthetic zone. These limitations may often necessitate the use of gingiva-colored "pink" restorative materials and essential preemptive planning via three-dimensional computeraided design/computer-assisted manufacture to achieve the desired esthetic outcome. The present report outlines a rationale for consideration of artificial gingiva when planning dental prostheses. Prosthetic gingiva can overcome the limitations of grafting and should be a consideration in the initial treatment plan.

Most biomechanical studies of implant-supported restorations have not taken into account the biologic changes that occur following exposure of the implants to the oral environment. Therefore, the present finite element analysis study was designed to compare the biomechanical response of three types of implant-abutment configurations both before and after establishment of a new biologic width. The three functional units studied were: a 5-mm implant platform connected with an external hexagon to a 5-mm-diameter abutment (type 1), a 5-mm implant platform connected with an external hexagon to a 4.1-mm-diameter abutment (type 2), and a 4.8-mm implant platform connected with an internal hexagon to a 4.1-mm-diameter abutment (type 3). The type 3 design, which combined platform switching with an internal connection, exhibited the smallest distortions in stress distribution after bone modeling, and the stress was distributed over the entire contact surface most smoothly and uniformly. Bone resorption following creation of the biologic width changes the biomechanical behavior of a restoration. In this study, the two implant-abutment designs featuring a smaller-diameter abutment on a largerdiameter implant platform achieved better results than the implant featuring the same-diameter implant platform and abutment, even though their initial biomechanical load potential was lower.

Socket or ridge preservation is performed to maintain the contour of the alveolar ridge prior to conventional or implant-based prosthetic therapy. In this retrospective analysis of consecutive subjects, a natural bone mineral containing collagen was grafted into 110 sockets in 62 patients. The sites were left open to heal. Based on external measurements with a periodontal probe, the soft tissue volume and contour were largely preserved at all sites, irrespective of the initial defect morphology. Clinical advantages of this protocol include predictable preservation of the soft tissues, favorable healing characteristics, and easy handling of the material.

The color stability of both porcelain and luting materials is very important for the esthetics of laminate veneers and all-ceramic crowns. The purpose of this study was to determine the effect of different shades of resin-based luting cement and the thickness of IPS Empress ceramics on the final color of the restorations. Resin-based dual-polymerized composite cement in two different shades (RelyX ARC) and ceramic disks of different thicknesses were selected for the study. Forty specimens (ten each of four different thicknesses: 0.5 mm, 1 mm, 2 mm, and 3 mm) were used for the evaluation. Initial specimen color parameters were determined in a Commission Internationale de l'Eclairage L*a*b* color order system with a colorimeter. Two different shades of the cement were prepared as polymerized layers and applied to one face of the specimens in order. Color changes were calculated between baseline color measurements and measurements after cementation. Color difference data were analyzed statistically. All specimens showed a significant color shift (ΔE > 3.7) after cementation regardless of the cement shade. However, the differences in the cement shade did not significantly affect the final color of the ceramic specimens for any thickness, and color shifts were not perceivable between the different shades of cement.

The purpose was to identify the effects of estrogen on the expression of alkaline phosphatase (ALP) and osteoprotegerin (OPG) in human periodontal ligament cells (hPDLCs). Cells were obtained from healthy periodontal tissue explants of teeth that had been extracted for orthodontic reasons. ALP activity was determined after 17ß-estradiol (17ß-E2) treatment at 0, 0.1, 1, 10, and 100 nmol/L by using assay reagents. OPG expression in hPDLCs was studied by enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction. It was shown that the ALP activity and the OPG protein production were increased in a time-dependent manner (P .05). Whereas a physiologic concentration of 17ß-E2 enhanced the secretion of OPG (P .05) and the expression of OPG mRNA, a high dose (100 nmol/L) of 17ß-E2 had no such effect on hPDLCs. It appears that estrogen may exert its antiresorptive effects and maintain periodontal health through stimulating ALP and OPG expression in hPDLCs.

Several surgical techniques, such as the papilla preservation flap, the modified papilla preservation flap, and the sulcular incision flap, have attempted to achieve clot stabilization and graft coverage in an attempt to regenerate lost tissue due to periodontal disease. This case report focuses on soft tissue root coverage and bone regeneration in a one-wall osseous defect using the pouch-and-tunnel surgical procedure. The pouch-and-tunnel surgical technique is a minimally invasive periodontal plastic surgical procedure that uses subepithelial connective tissue as a free graft in a pouch beneath the gingival margin, created by sulcular incisions around the involved teeth. The autogenous bone graft placed in this one-wall osseous defect through a sulcular incision after root planing is protected in a stable pouch-like recipient site with an abundant blood supply. The free connective tissue graft also prevents epithelial migration into the recipient site. The use of Emdogain may help with cementogenesis around the planed root surface. This technique warrants further evaluation of cases with similar defects using this surgical procedure.

In this study, a new type of distraction implant (DI) that could be transformed into a prosthetic implant after distraction was applied to augment the alveolar ridge, and the bone response around it was observed in six dogs. Two DIs were placed into the lateral edentulous submandibular ridge after osteotomy. The DIs were left to integrate into the bone after 8 days of distraction at a rate of 1 mm per day. Specimens were obtained at 5, 8, and 12 weeks after distraction. Radiopacity of the regenerated bone increased steadily during the consolidation period. After 12 weeks, homogeneous bone density was observed. Histologic examination showed osseointegration of the whole DI in the region of the threads in the native bone and in the regenerated area 12 weeks later. These results suggest that simultaneous bone regeneration in a distracted gap and osseointegration of DIs in an augmented alveolar ridge can be achieved. The overall treatment time could be shortened significantly with this method.

The perceptions of dental professionals and laypeople were compared with respect to relative gingival marginal levels of the lateral incisors, flatness of the gingival margin of central incisors and its variations in horizontal locations, and interproximal contact length relative to gingival biotype. The distribution of toothgingiva topography in periodontally healthy subjects was also identified. A noticeable difference was observed between dental professionals and laypeople in their perception of maxillary anterior esthetic components. Normal distribution of the topographic features of anterior teeth and gingiva delineated an intermediate biotype between those preferred by dental professionals and those preferred by laypeople. The present study clearly indicates that dental professionals and laypeople demonstrated significant differences in their perceptions of dental esthetic components. These differences may influence the decision-making process by dental professionals with respect to designing the gingival levels of lateral incisors, the horizontal gingival contours of central incisors, and the shape of interproximal contact areas.

The use of biodegradable fixation materials or devices during maxillofacial, craniofacial, and orthopedic reconstructive surgical procedures reduces or eliminates the need to perform a second surgical procedure, which would otherwise be required to remove a nonbiodegradable device. This article presents a novel approach to augment a horizontally deficient alveolar ridge using both a resorbable plate/screw fixation system composed of a polylactic acid-polyglycolic acid (PLLA-PGA) copolymer to provide a rigid scaffolding for the bone chips and a resorbable collagen barrier (Bio-Gide, Osteohealth) to secure the graft material. For periodontal reconstructive procedures, such as guided bone regeneration, the clinical application of this technique may be advantageous and also provide a more esthetic result by minimizing the need for an additional surgical procedure.

The aim of this study was to evaluate the early phases of bone healing around two different implant surfaces. For this purpose, four minipigs were used. Implants with rough titanium surfaces (ITI sandblasted/acid-etched and Brånemark TiUnite) were placed in the maxillae of the animals and sacrifice was scheduled in such a way that healing times of 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, and 7 weeks were obtained. Histologic analysis revealed that a similar pattern was observed in the phases of bone healing around both types of implants between 3 days and 7 weeks. This pattern consisted of the replacement of blood clot and bone debris with a provisional connective tissue in the first few weeks and with mineralized tissue and marrow spaces later on. Both rough surfaces allowed for "contact osteogenesis" to take place.