Changing concepts in periodontics

Gingival esthetics: an orthodontic and periodontal approach

INTRODUCTION: Currently, people's esthetic requirements and expectations have increased substantially. Therefore, dentists have been seeking ways to provide excellent treatment results which, consequently, increasingly require a well organized transdisciplinary approach. The link between orthodontics and periodontics became evident from the moment professionals began to understand the biology of tooth movement. As regards smile esthetics, however, such cooperation is now essential. OBJECTIVE: To show clinically how and when orthodontists and periodontists should work jointly to enhance smile esthetics based on the display and harmony of the gingival contour.

Evaluating the validity of probing attachment loss as a surrogate for tooth mortality in a clinical trial on the elderly

Most periodontal trials are based on the assumption that the superior treatment, as judged by short-term intangible changes in probing attachment levels (the surrogate), is also the treatment most likely to affect tooth mortality. This assumption is valid if: (1) the surrogate is informative about tooth mortality, and (2) the surrogate captures a substantial proportion of the treatment effect on tooth mortality (e.g., > 50% or 75%). The goal of this study was to evaluate whether both conditions were satisfied in a randomized controlled trial (RCT) of elders at high risk for dental diseases. The results suggested that the first condition for a valid surrogate was satisfied: Both one- and two-year changes in probing attachment level were informative about tooth mortality risk. A 1-mm loss measured over a one-year period was associated with a 56% increased tooth mortality risk (relative risk = 1.56; 95% confidence interval, 1.08 to 2.26; p = 0.017); a 1-mm loss measured over a two-year period was associated with a 102% increased risk for tooth mortality (relative risk = 2.02; 95% confidence interval, 1.26 to 3.25; p = 0.004). The second condition necessary for a valid surrogate could not be confirmed in the present trial. With 95% confidence, it was concluded that one-year changes in probing attachment level measurements did not capture a significant proportion of the treatment effect (point estimate, 6%; 95% confidence interval;-38% to 53%). No useful statements could be made regarding the proportion of treatment effect captured by two-year changes, due to the width of the confidence interval (point estimate, 18%; 95% confidence interval;-151% to 140%). It is concluded that (1) the evidence surrounding the one-year change in probing attachment level indicates that it can be ruled out as being anything more than a weak surrogate marker for tooth mortality, and (2) further research is required to study the validity of two-year change in probing attachment level as a surrogate marker. Due to characteristics of the population and the treatments investigated, the generalizability of these findings to other RCTs is questionable.

Clinical implications of recent orthodontic-periodontic research findings

During the past 15 years, advances in basic science related to periodontal biology, and clinical trials on prevention and treatment of periodontal disease, have dramatically changed many treatment concepts in periodontics. The most pertinent information for orthodontic practice from these studies is summarized. Also, recent advances in orthodontics, particularly regarding bonding of attachments to artificial tooth surfaces and improved long-term stabilization of orthodontic treatment results in adults by means of bonded lingual retainers have significant implications. This article outlines how recent research information from both dental specialties may be used by orthodontists to improve treatment planning, clinical management, and retention of their adult and elderly patients in whom different malocclusions are complicated by moderate to advanced periodontal destruction.

A survey of endpoint characteristics in periodontal clinical trials published 1988-1992, and implications for future studies

Endpoints are conditions or events that are associated with individual study subjects and that are used to assess treatment efficacy. 2 types of endpoints can be distinguished: "true" endpoints (reflect unequivocal evidence of tangible benefit to the patient) and "surrogate" endpoints (usually a measure of disease process). The purpose of this study was to survey four aspects of endpoint usage in randomized controlled trials (RCT's) on the treatment of periodontitis: (1) the typical number of endpoints per RCT, (2) the proportion of RCTs using the same endpoint, (3) the proportion of RCTs using true endpoints, and (4) whether treatment choice influenced endpoint choice. 92 publications (1988-1992) reporting on 82 RCT's were identified. The typical number of endpoints per RCT was 6 (range: 1-28). The 3 most frequently used endpoints were mean probing depth (78% of the trials), mean probing attachment level (66%), and the plaque index (37%). In total, 153 distinct surrogate endpoints were defined. Most of these were used infrequently; over 80% of the 153 endpoints were used in fewer than 5 of the 82 trials. No trials used tooth loss as a true endpoint. In the design of an RCT, treatment choice influenced surrogate endpoint choice. Surrogate endpoints based on re-entry surgery were exclusively used for regenerative procedures and microbiological surrogate endpoints were mostly used for RCT's on anti-microbials. The conclusion is that the typical RCT used multiple surrogate endpoints, some of which were used infrequently by other trials. Such endpoint usage characteristics are suitable for exploratory RCTs (designed to identify active treatments or to elucidate treatment mechanisms). The question is raised as to whether periodontal research has reached the point of needing properly designed definitive studies, whose purpose it would be to provide unequivocal evidence of tangible benefits to the patient by the various treatments. If a need for definitive randomized controlled trials is perceived, then the use of (multiple) surrogate endpoints as primary outcomes should be questioned. Surrogate endpoint usage has led to both false positive and false negative conclusions in other chronic disease studies. Endpoint selection and validation in RCTs may be an important element in resolving controversies about periodontal treatments.

Autogenous and allogeneic bone grafts in periodontal therapy

This article is limited to a review of bone autografts and allografts, as used in periodontal therapy. The various graft materials are discussed with respect to case reports, controlled clinical trials, and human histology. Other reviewed areas are wound healing with periodontal bone grafts, tissue banking and freeze-dried bone allografts, and the use of bone grafts in guided tissue regeneration.

Gingival margins for crowns: a review and discussion. Part II: Discrepancies and configurations

While there is variation regarding the maximum acceptable marginal discrepancy, there is little argument that poorly fitting margins are a frequent finding. Large discrepancies are clinically significant, since they facilitate plaque retention. Margins incorporating slip joint geometry have usually been favored as a method of minimizing seating and sealing discrepancies. However, many of these discussions largely ignored the effects of the cementing medium and the clinical applicability of slip joint geometry is based on questionable assumptions with regard to casting accuracy and seating. Greater understanding of the role of restorative margins and gingival health indicates the need for shallow margin placement within the crevice, which requires a reassessment of the use of long bevels. Horizontal margins can be made accurately and, when combined with procedures to maximize crown seating, may provide the best method of minimizing seating discrepancies and maximizing gingival health.

Causes of tooth loss in a veteran population

Tooth loss in adults over age 35 usually is attributed to periodontal diseases. However, certain adult populations are known to have high caries rates. It is not clear to what extent caries contributes to tooth loss in adults. This pilot study examined the causes of tooth loss in a veteran population residing in an 800-bed, primarily long-term care facility. The study retrospectively reviewed 572 patients' dental records and documented causes for dental extractions. Of the sample population, 168 teeth were extracted in 51 patients who had 860 teeth present before treatment. Mean age of the patients undergoing extractions was 57.7 years, lower than the sample population of 60.1 years. Of the 168 teeth extracted, 105 (63%) were attributed to caries and 33 (20%) were documented as root tips, suggesting the presence of root caries. Fifty-five (33%) were extracted due to periodontal disease and six (4%) were extracted for prosthodontic reasons. Of the maxillary teeth, 67 percent were extracted for caries and 25 percent of periodontal reasons. Caries accounted for 57 percent and periodontal disease accounted for 42 percent of the mandibular teeth extracted. The order in which teeth were most frequently extracted was maxillary anteriors, mandibular anteriors, maxillary and mandibular premolars, and maxillary and mandibular molars. This study supports the recent work of authors who have found caries contributing significantly to tooth loss in adult populations.

Hemisection and root amputation

The disciplines of endodontics and periodontics fuse when molars that have bifurcation or trifurcation involvements are treated with hemisection and root amputation. Attempts to save parts of teeth go back 100 years or more, but it is the increased predictability of success of endodontic therapy and the increased sophistication of periodontal treatment that have given us the means to save molars with furcation problems that, otherwise, would be lost. Even when less invasive modes of therapy have failed (scaling, root planing, occlusal adjustment, and flap surgery perhaps with osseous recontouring and synthetic or natural bone grafting material where indicated), it is no longer necessary to lose a molar with complete furcation problems. When restorative dentistry has already been finished, and the retention of part of the tooth will extend the life of a crown or fixed partial denture, the patient certainly deserves the option of hemisection or root amputation rather than extraction.