A 15-year study of osseointegrated implants in the treatment of the edentulous jaw

Background Authors were assigned the task to develop case definitions for periodontitis in the context of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. The aim of this manuscript is to review evidence and rationale for a revision of the current classification, to provide a framework for case definition that fully implicates state-of-the-art knowledge and can be adapted as new evidence emerges, and to suggest a case definition system that can be implemented in clinical practice, research and epidemiologic surveillance. Methods Evidence gathered in four commissioned reviews was analyzed and interpreted with special emphasis to changes with regards to the understanding available prior to the 1999 classification. Authors analyzed case definition systems employed for a variety of chronic diseases and identified key criteria for a classification/case definition of periodontitis. Results The manuscript discusses the merits of a periodontitis case definition system based on Staging and Grading and proposes a case definition framework. Stage I to IV of periodontitis is defined based on severity (primarily periodontal breakdown with reference to root length and periodontitis-associated tooth loss), complexity of management (pocket depth, infrabony defects, furcation involvement, tooth hypermobility, masticatory dysfunction) and additionally described as extent (localized or generalized). Grade of periodontitis is estimated with direct or indirect evidence of progression rate in three categories: slow, moderate and rapid progression (Grade A-C). Risk factor analysis is used as grade modifier. Conclusions The paper describes a simple matrix based on stage and grade to appropriately define periodontitis in an individual patient. The proposed case definition extends beyond description based on severity to include characterization of biological features of the disease and represents a first step towards adoption of precision medicine concepts to the management of periodontitis. It also provides the necessary framework for introduction of biomarkers in diagnosis and prognosis.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/jcpe.12945

Staging and grading of periodontitis: Framework and proposal of a new classification and case definition.

The present experiment was undertaken to test the hypothesis that new connective tissue attachment may form on a previously periodontitis involved root surface provided cells originating from the periodontal ligament are enabled to repopulate the root surface during healing. A mandibular incisor with advanced periodontal disease of long standing (the distance between the cemento-enamel junction and the alveolar bone crest was 9 mm) was subjected to periodontal surgery using a technique which during healing prevented the dentogingival epithelium and the gingival connective tissue from reaching contact with the curetted root surface. Preference was hereby given to the periodontal ligament cells to repopulate the previously diseased root surface. After 3 months of healing a block biopsy containing the incisor and surrounding tissue was sampled. The histological analysis revealed that new cementum with inserting principal fibers had formed on the previously diseased root surface. This new attachment extended in coronal direction to a level 5 mm coronal to the alveolar bone crest. This finding suggests that new attachment can be achieved by cells originating from the periodontal ligament and demonstrates that the concept that the periodontitis affected root surface is a major preventive factor for new attachment is invalid.

New attachment following surgical treatment of human periodontal disease.

Healing events after nonsurgical periodontal therapy in patients with periodontal pockets 4--7 mm deep were investigated. Incisors, cuspids and premolars in 15 patients were treated by plaque control and supra- and subgingival debridement using hand or ultrasonic instruments in a split mouth approach. The results were evaluated by recordings of plaque scores, bleeding on probing, probing pocket depths and probing attachment levels. All these parameters were improved during the initial 4--5 months after start of therapy. Little change occurred during the rest of the 13-month observation period. No difference of results could be observed comparing hand and ultrasonic instrumentation or comparing the results of two different operators. Initially a total of 106 sites demonstrated probing pocket depths greater than or equal to 6 mm. At 13 months only 13 such sites were observed. The apparently successful results of conservative treatment of patients with 4--7 mm deep pockets in the present study raise the question to what extent nonsurgical therapy is feasible also in patients with severely advanced lesions.

Effect of nonsurgical periodontal therapy. I. Moderately advanced periodontitis.

Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist. Further, there are extraradicular factors -- located within the inflamed periapical tissue -- that can interfere with post-treatment healing of apical periodontitis. The causes of apical periodontitis persisting after root canal treatment have not been well characterized. During the 1990s, a series of investigations have shown that there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. These are: (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion. This article provides a comprehensive overview of the causative factors of non-resolving periapical lesions that are seen as asymptomatic radiolucencies post-treatment.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-2591.2006.01099.x

On the causes of persistent apical periodontitis: a review.

The present investigation describes the effect of periodontal therapy in a group of patients who, following active treatment, were monitored over a 5-year period One aim of the study was to analyze the role played by the patients' self-performed plaque control in preventing recurrent periodontitis In addition, probing depth and attachment level alterations were studied separately for sites with initial probing depths of greater than or equal to 4 mm which were treated initially by either surgical or non-surgical procedures Following active treatment (surgical/non-surgical), the patients were maintained on a plaque control regimen for 6 months, which included professional tooth cleaning once every 2 weeks During the subsequent 18 months, the interval between the recall appointments was extended to 12 weeks and included prophylaxis as well as oral hygiene instruction Following the 24-month examination, the interval between the recall appointments was further extended, now to 4-6 months In addition, the maintenance program was restricted to oral hygiene instruction and professional, supragingival tooth cleaning, but further subgingival instrumentation was avoided Clinical examinations including assessments of the oral hygiene, the gingival conditions, the probing depths and the attachment levels were performed at Baseline and after 24 and 60 months after completion of active therapy Assessments of plaque and gingivitis were repeated annually The results of the examinations showed that the patients' standard of self-maintained oral hygiene had a decisive influence on the long-term effect of treatment Patients who during the 5 years of monitoring consistently had a high frequency of plaque-free tooth surfaces showed little evidence of recurrent periodontal disease, while patients who had a low frequency of plaque-free tooth surfaces had a high frequency of sites showing additional loss of attachment The present findings demonstrated that sites with an initial pocket depth exceeding 3 mm responded equally well to non-surgical and surgical treatments This statement is based on probing depth and attachment level data from sites which were free of plaque at the 6-, 12-, 24-, 36-, 48-, and 60-month reexaminations It is suggested that the critical determinant in periodontal therapy is not the technique (surgical or non-surgical) that is used for the elimination of the subgingival infection, but the quality of the debridement of the root surface

Long‐term effect of surgical/non‐surgical treatment of periodontal disease

The aim of the present experiment was to study whether new connective tissue attachment can occur to root surfaces which have been exposed to the oral environment and subsequently implanted into bone tissue. Twelve teeth in three beagle dogs were subjected to progressive periodontal breakdown to half the root length by placing cotton floss ligatures around the neck of the teeth. Following crown resection and root hemisection, the teeth were root filled and the roots thoroughly scaled and planed. Each root was extracted and implanted into bone cavities prepared in edentolous areas of the jaws in such a way that epithelial migration into the wound and bacterial infection were prevented during healing. Root implantation and sacrifice of the animals were scheduled to allow for observation periods of 1, 2 and 3 months. The results demonstrated that new connective tissue attachment did not occur to root surfaces which had been exposed to the oral environment, but healing was characterized by repair phenomena, i. e. mainly root resorption and ankylosis. In those areas of the roots where periodontal ligament tissue was preserved following tooth extraction, a functionally oriented attachment apparatus was reformed. The results indicate that in addition to apical migration of junctional epithelium and regrowth of subgingival plaque, the type of cells which repopulate the wound area may jeopardize new connective tissue attachment.

Healing following implantation of periodontitis affected roots into bone tissue.

A clinical trial was undertaken to study the healing capacity of the periodontal tissues following different modes of periodontal surgery in patients whose oral hygiene was professionally maintained at an optimal level. Fifty patients, distributed into five groups, participated in the study. Following an initial examination and presurgical treatment, the various patient groups were subjected to one of the following surgical procedures: 1) the apically repositioned flap operation including elimination of bony defects, 2) the apically repositioned flap operation including curettage of the bony defects but without removal of bone, 3) the “Widman flap” technique including elimination of bony defects, 4) the “Widman flap” technique including curettage of the bony defects but without removal of bone, 5) gingivectomy including curettage of the bony defects but without removal of bone. After surgery, all patients received oral hygiene instruction and professional cleaning of the teeth once every 2 weeks during a 2-year period.

The results showed that periodontal disease can be cured and further destruction of the periodontal tissues avoided irrespective of the surgical technique utilized for pocket elimination. Different surgical techniques, however, promoted varying degrees of regeneration of the supporting tissues. The most favourable healing was obtained when resection of bone was avoided and when complete coverage of the alveolar bone was ensured.

The healing potential of the periodontal tissues following different techniques of periodontal surgery in plaque-free dentitions. A 2-year clinical study.

The investigation was undertaken to find out whether favourable conditions for healing after periodontal surgery would develop in patients whose oral hygiene was professionally maintained at a high standard. The study was performed on 20 patients with advanced periodontal disease. Following an initial examination, comprising plaque index and gingival index scoring, measurement of pocket depths and loss of attachment, the patients were randomly distributed between a test and a control group. The patients first received professional cleaning of the teeth once every 2 weeks. The patients of the control group were recalled for scaling of the teeth once every 6 months. All patients were reexamined after 6, 12 and 24 months. It was found that the control patients were unable to maintain a high standard of oral hygiene with the result that the treatment of the periodontal disease failed. The patients of the test group maintained a high standard of oral hygiene, and the treatment of the periodontal disease was, therefore, successful.

Effect of professional tooth cleaning on healing after periodontal surgery.

The present investigation was carried out on 15 individuals who were referred for treatment of moderately advanced periodontal disease. All patients were first subjected to a Baseline examination comprising assessment of oral hygiene and gingival conditions, probing depths and attachment levels. Following case presentation and instructions in oral hygiene measures, the patients were given periodontal treatment utilizing a split mouth design. In one side of the jaw scaling and root planing were performed in conjunction with a modified Widman flap procedure while in the contralateral jaw quadrants the treatment was restricted to scaling and root planing only. The period from initial treatment to 6 months after treatment was considered to be the healing phase and from 6-24 months after treatment the maintenance phase. During the healing phase the patients were recalled for professional tooth cleaning once every 2 weeks. During the maintenance phase the interval between the recall appointments was extended to 3 months. Reexaminations were carried out 6, 12 and 24 months after the completion of active treatment. The results revealed that treatment resulted in loss of clinical attachment in sites with initially shallow pockets, while sites with initially deep pockets gained clinical attachment. With the use of regression analysis "critical probing depths" were calculated for the two methods of treatment used. It was found that the critical probing depth value for scaling and root planing was significantly smaller than the corresponding value for scaling and root planing used in combination with modified Widman flap surgery (2.9 vs 4.2 mm). In addition, the surgical modality of therapy resulted in more attachment loss than the non-surgical approach when used in sites with initially shallow pockets. On the other hand, in sites with initial probing depths above the critical probing depth value more gain of clinical attachment occurred following Widman flap surgery than following scaling and root planing. The data obtained from the reexaminations 12 and 24 months after active treatment demonstrated that the probing depths and the attachment levels obtained following active therapy and healing were maintained more or less unchanged during a maintenance care period which involved careful prophylaxis once every 3 months. However, the data also disclosed that the level of oral hygiene maintained by the patients during healing and maintenance was more critical for the resulting probing depths and attachment levels than the mode of initial therapy used.(ABSTRACT TRUNCATED AT 400 WORDS)

S. Nyman

Papers

Long‐term effect of surgical/non‐surgical treatment of periodontal disease

Healing following implantation of periodontitis affected roots into bone tissue.

The healing potential of the periodontal tissues following different techniques of periodontal surgery in plaque-free dentitions. A 2-year clinical study.

Effect of professional tooth cleaning on healing after periodontal surgery.

“Critical probing depths” in periodontal therapy