International Journal of Periodontics & Restorative Dentistry, 06/2002

Prompted by increased patient requests for esthetic treatment, restorative clinicians have evaluated a variety of new materials and procedures. This study reports on 5 years' experience with In-Ceram Spinell all-ceramic crowns. A total of 40 anterior crowns were positioned in 13 patients from October 1995 to December 1998. The clinical examination was made following modified California Dental Association/Ryge criteria. Final evaluation was carried out in October 2000, for an observation period of 22 to 60 months (mean 50 months). Only one failure was recorded, and the fractured crown needed to be replaced; according to Kaplan- Meier analysis, the estimated success rate was 97.5%. A thorough description of the clinical procedures through which anterior teeth can be successfully treated with all-ceramic Spinell crowns is described.

This article introduces a new technique using histomorphometrics to estimate the extent of bone-to-implant contact that might be expected on an implant surface in relation to the quality of the surrounding bone. Two implant surfaces, one machined and one Osseotite, were compared on the same implant in the same patient. Eleven of these custom-made 2-mm-diameter implants were placed in the posterior maxilla and allowed to integrate. After 6 months of nonloaded healing, implants were trephined with surrounding bone tissue and prepared into histologic sections. Digitized images were analyzed at 50X magnification with image-analysis software. Bone surface area was calculated over the entire microscopic field, and the actual bone-to-implant contact for each implant surface was measured. The expected bone-to-implant contact was calculated by superimposing the profile of the implant threads on the bone image a small increment (0.15, 0.5, or 1.0 mm) from the actual implant site and counting the linear amount of bone that would be in contact with the implant surface. The actual bone-to-implant contact for Osseotite was greater than its expected bone-to-implant contact, whereas the actual bone-to-implant contact for the machined surface was mostly lower than the expected values. Thus, the Osseotite surface appears to exert a positive effect on the amount of bone approaching the implant surface and can be described as conductive, while the machined surface is nonconductive. This technique may serve to predict the clinical success that the Osseotite surface will demonstrate in poor-quality bone.

Autologous platelet-rich plasma is a source of platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF-ß), both important in accelerating hard and soft tissue maturation. This article describes a two-step centrifugation method to sequester and concentrate platelets to a level four to eight times baseline whole blood values. The technique produces concentrations of PDGFAB above 500% and TGF-ß1 greater than 800%. Flow cytometry measuring pselectin expression shows that the platelets remain quiescent throughout the procedure, maintaining their integrity and viability, with no inadvertent activation.

We describe a case of gingival recession in which root coverage and coronal bone regrowth were achieved after treatment with a connective tissue-bone graft and enamel matrix derivative. The connective tissue-bone graft was harvested from a maxillary edentulous area and then curved to fit the root surfaces of the maxillary left central and lateral incisors. Enamel matrix derivative was applied to the root surfaces, and the connective tissue-bone graft was fixed to the interdental bone by a titanium screw. Six months later, the exposed roots were covered with thick gingiva, and coronal regrowth of thick bone was evident at reentry surgery. This technique is useful for esthetic restoration placement with an intracrevicular margin on teeth with a thin, receding gingiva.

This article describes a clinical case report in which an autogenous intraorally harvested block graft was used in combination with particulate autogenous and inorganic bovine mineral for localized alveolar ridge augmentation. No barrier was used above the graft material. Clinical evaluation revealed excellent integration of the graft material to the recipient site, while histologic analysis indicated that the block graft was vital and undergoing an active remodeling process. Excellent integration of the inorganic bovine mineral with the newly formed bone was also observed, suggesting that this material can be used as a filler for onlay grafting procedures.

A submerged hydroxyapatite (HA)-coated implant placed into a fresh extraction socket in conjunction with a nonresorbable HA graft was harvested after 6 years of unloaded healing. The implant and surrounding bone were processed for histologic analysis. The HA coating appeared to be stable and homogenous. An excellent bone-to-implant contact could be found along the entire implant length. No signs of HA resorption or detachment were found. The HA graft was still recognizable histologically around the apical third of the implant. Light microscopy revealed a good osteoconductive ability of the HA particles, which did not show any signs of remodeling or resorption. These findings suggest that HA-coated implants may be able to maintain optimal osseointegration over time, even in the absence of loading.

This article describes two different surgical techniques of root coverage using Emdogain and shows preliminary results on 26 shallow recessions in 14 patients. For the treatment of 13 recessions, Emdogain was used in combination with a coronally advanced flap (CAF+EMD group). In the other 13 recessions, Emdogain and the flap were used in combination with a subepithelial connective tissue graft (CAF+CTG+EMD group). For the CAF+EMD group, the root coverage at 6 months was 93.97%, with an attachment gain of 3.2 mm; for the CAF+CTG+EMD group, the root coverage was 93.59%, with an attachment gain of 3.4 mm (no statistically significant difference between groups). When complete root coverage was not achieved, the residual recession was 1 mm in four cases and 2 mm in one case. Keratinized gingiva was increased for both groups, but more for the CAF+CTG+EMD group (1.38 mm versus 0.69 mm; statistically significant difference). Clinical attachment level decreased significantly in both groups, from 4.46 to 1.23 mm in the CAF+EMD group, and from 4.62 to 1.23 mm in the CAF+CTG+EMD group. Preliminary results show that Emdogain, in combination with CAF or CAF+CTG for the treatment of Miller Class I or II gingival recessions, displays good clinical results, with percentage of root coverage comparable or superior to other techniques. Further experimental studies on the dynamics of wound healing are needed to prove that EMD is really responsible for improving the percentage of regenerated versus repaired tissues with respect to other techniques.

Recent clinical study shows that periodontal regeneration therapy using enamel matrix proteins (Emdogain; EMD) is expected to have the same therapeutic effect as guided tissue regeneration (GTR). However, reports on the combined effect of both therapies are limited, and the clinical significance is not definite. In this study, clinical effects were studied by comparing a combination of EMD and GTR using a collagen membrane for intrabony defects with GTR monotherapy and EMD monotherapy. Sixty-one patients with 69 intrabony defects were included. Efficacy of treatment was evaluated at 6 months and 1 year by assessment of reduction of probing depth, probing attachment gain, and radiographic bone gain. There were no statistically significant differences between presurgical soft tissue measurements and defect characteristics for the three treatment groups. The results showed no significant differences in reduction of probing depth, probing attachment gain, or radiographic bone gain between the three treatment groups at both evaluation times. The combination of GTR using a resorbable membrane for intrabony defects and EMD did not enhance the therapeutic effect compared with each monotherapy.

Although keratinized mucosa is not indispensible for the maintenance of periimplant tissue health if oral hygiene is adequate, its presence is generally advocated. The establishment of an adequate zone of gingiva that is firmly attached to the underlying periosteum and bone is important for the overall long-term success of implant-supported oral rehabilitation. The purpose of this study was to describe and evaluate a surgical approach for maxillary implant uncovering that augments the buccal periimplant keratinized tissue while avoiding a large zone of exposed implant-supporting bone by using a rotated palatal flap. The study comprised 40 implants that were uncovered in 13 patients using a combination of fullthickness buccally repositioned and rotated palatal flaps. Within each patient, the mean preoperative width of keratinized mucosa was 0.19 mm (SD 0.316), and the mean postoperative width was 3.45 mm (SD 0.489). The difference between post- and preoperative widths was 3.26 mm (SD 0.498), which was statistically significant according to a paired t test (P .0001). The main advantages of this technique are simplicity and predictability, and it consistently provides a wider zone of keratinized gingiva in the buccal aspect of the future maxillary implantsupported restoration.