International Journal of Periodontics & Restorative Dentistry, 05/1998

The purpose of this review was to examine the periodontal and restorative factors related to restoring teeth with short clinical crowns. Modes of therapy are usually combined to meet the biologic, restorative, and esthetic requirements imposed by short clinical crowns. The complications presented by teeth with short clinical crowns demand a comprehensive treatment plan and proper sequencing of therapy to ensure a satisfactory result. Visualization of the desired result is a prerequisite of successful therapy. Short clinical crowns present many problems to the restorative dentist. Restorations should have proper form, function, and esthetics while promoting the maintenance of tissue health in the surrounding areas. However, adequate tooth structure for achieving these goals may not always be available. While it is difficult to precisely define minimum crown length, this study offers guidelines for defining a short clinical corwn and suggests procedures for achieving a predictable result without compromising the periodontium. The consequences of placing a restoration on a tooth with insufficient crown length are discussed and various treatment methods are reviewed.

The aim of this retrospective study was to evaluate the predictability of obtaining a vertical ridge augmentation around dental implants, strictly following a surgical protocol. Fourteen partially and four fully edentulous patients were treated between July 1993 and November 1995. Forty-eight consecutive implants were placed so that the circumference of the upper part of the cover screw was exposed from 2 to 7 mm. In addition to bone chips, autogenous bone grafts harvested with a bone-filtering aspirator were placed around the exposed threads and completely covered with a barrier membrane. Flaps were coronally displaced to cover the regenerative materials. Three of the 22 membranes became exposed prematurely and were removed immediately. The remaining 19 membranes stayed in place for a 12-month healing period until the second-stage surgery. In these 19 cases, where the membrane remained completely covered by the soft tissue, all of the available space underneath the membrane was filled with regenerative tissue. In eight cases a histologic biopsy was performed. Histologic analysis demonstrated vital bone with regularly formed bone cells; in three cases the most coronal part (approximately 1 mm) of the regenerative tissue was connective tissue, and the remaining tissue was bone. This retrospective analysis showed that when the clinical protocol was accurately followed, the possibility of clinical complication was reduced and the results for achieving vertical ridge augmentation around implants were predictable.

Twenty buccogingival recessions (3 mm deep) in twenty patients were selected and divided into two groups. Periodontal parameters were recorded (recession reduction, probing depth, clinical attachment level, and keratinized tissue width), and both groups were treated with regenerative therapy using a resorbable polylactic acid membrane. The test group was treated using the double papilla flap procedure, and the control group was treated using the coronally repositioned flap procedure. The results obtained at a 1-year follow-up were comparable between the test and control groups for recession reduction, probing depth, and clinical attachment level, although the test group obtained a very large amount of keratinized gingiva (+ 74.7%) compared to the control group.

In the pursuite of esthetic restorations for nonvital teeth, the introduction of a tooth-colored intraradicular post system is described. Conventional metallic posts can corrode and may cause inflammatory reactions and discoloration of the periodontium. Zirconium dioxide is a chemically stable ceramic with physical and optical properties that make it an ideal choice for the construction of esthetic, life-like restorations. The purpose of this study was to describe the composition, properties, and practical applications of zirconia posts in clinical practice.

The traditional goal of disease elimination in the anterior region opens the interproximal spaces, causing flattening or cratering of the interdental papilla. Today's patients increasingly demand esthetic results in addition to periodontal treatment, and recent advances in periodontal plastic surgery have enhanced the periodontist's ability to address these concerns. Three case reports demonstrate a proposed surgical technique for the reconstruction of collapsed interdental papillae using a connective tissue graft under the buccal and palatal flaps

Tissue reactions to natural and synthetic braided and monfilament suture materials in gingiva and oral mucosa were studied. A total of 138 sutures made of four commonly used materials were placed in the edentulous ridges and vestibutlar mucosa of eight beagle dogs. Biopsy specimens including the suture loop and surrounding tissues were obtained after 3, 7, and 14 days and processed for histolgoic analysis. The inflammatory reaction was more rapid and intense than the reaction that has been reported after suture placement in skin. Bacterial invasion of the sutu re track was a common sequela regardless of the material used, but it was particularly prominent for silk. The formation of a perisutural epithelial sleeve was well under way at 3 days and in some instances included the entire suture track within 7 days. Connective tissue reactions consisted of several well-defined, concentric perisutural zones. At 14 days, these zones were partly replaced by granulation tissue surrounded by a fibrous capsule. The synthetic monofilament suture elicited a mild inflammatory tissue response. The results showed that sutures placed in gingiva and oral mucosa produce a prolonged tissue response that is most likely a result of the continual influx of microbial contamination aslong the suture channel, which may be a lesser problem when sutures are placed in other surgical compartments. The results indicate that chromic gut sutures are rapidly and unpredictably absorbed when used in an environment characterized by moisture and infectious potential.

The objective of the present study was a morphometric and morphologic analysis of maxillary and mandibular first and second molars using three different techniques. Measurements of 207 maxillary molars (105 first and 102 second molars) and 207 mandibular molars (110 first and 97 second molars) were measured; root length, radicular trunk length (RTL), mesiodistal and buccolingual diameters (BLD) at the cementoenamel junction, inter-radicular angle (IRA) width, and furcal roof area (FRA) were recorded. No significant statistical correlations were found for most of these measurements, the only exception being the relationship between IRA/FRA, IRA/BLD in maxillary molars, and IRA/RTL in the maxillary first molar. Morphologic examination was carried out by stereo microscopy, light microscopy of undecalcified sections, and scanning electron microscopy. All of thse techniques showed the complexity of the furcation area with a large number of anatomic irregularities and plaque-retentive structures that could hamper adequate cleaning during peridoontal treatment.

Created periodontal defects in dogs were randomly assigned for experimental (Guidor bioresorbable membranes) or control (conventional therapy) treatment. The results showed t hat the new connective tissue attachment was significantly greater in test sites than in controls. This new attachment averaged 2.79 ± 0.74 mm and 1.47 ± 0.20 mm at test and control sites, respectively (P 0.05). Epithelial downgrowth was also reduced in the test sites (P 0.05). No differences in bone response were found. The bioresorbable barrier was effective in blocking gingival epithelial downgrowth and connective tissue proliferation, promoting new attachment according to the principles of guided tissue regeneration.