Overdentures and the periodontium.

Several periodontal factors are critical to the prognosis of overdenture abutment teeth. This literature review outlines these factors and discusses the documented effects of long-term overdenture use on periodontal health. The efficacy of a professional periodontal maintenance program, which is coordinated with a home oral hygiene program, is related to the success of overdenture therapy.     

Effect of controlled oral hygiene in overdenture wearers: a 3-year study.

The effect of controlled oral hygiene was studied in 35 overdenture patients involving 80 abutments over a period of 3 years. Intensive instruction and motivation in oral hygiene care were carried out prior to prosthodontic treatment and two to four times yearly during the study period. The initial dental and periodontal conditions were very poor, with a mean loss of proximal bone adjacent to the abutments of 62% +/- 17%. During the study period, it was possible to maintain mean plaque index scores of 0.40 to 0.70 and mean gingival index scores of 0.90 to 0.98 adjacent to the abutments. There was spontaneous regression of 4- to 5-mm periodontal pockets, whereas deeper pockets persisted. There was no relationship between the patients' initial plaque index score and the oral and denture hygiene observed during the study. The results of the study showed that it was possible to maintain teeth as overdenture abutments in elderly patients initially having a poor dental and periodontal status.     

Prognosis of overdenture abutments in elderly patients with controlled oral hygiene. A 5 year study

summary The effect of controlled oral hygiene was studied in 31 elderly overdenture patients involving 72 abutments over a period of 5 years. Intensive instruction and motivation in oral hygiene care were carried out prior to prosthodontic treatment and two to four times yearly during the study period. The initial dental and periodontal conditions were very poor, with a mean loss of proximal bone adjacent to the abutments of 61%. During the study period, it was possible to maintain mean plaque index scores of 0.45−0.73 and mean gingival index scores of 0.89−0.95 adjacent to the abutments. There was no relationship between the patients' initial plaque index score and the oral and denture hygiene observed during the study. There was spontaneous regression of 4–5 mm periodontal pockets, whereas deeper pockets persisted. Seven abutments were extracted due to periodontal complications. Caries was a minor problem which could be controlled by hygienic measures, topical fluoride or fillings. The present study has shown that it was possible to maintain teeth as overdenture abutments to a large extent in elderly patients initially having a poor dental and periodontal status.     

A 10-year report of a longitudinal recall of overdenture patients

Eighty-nine patients were evaluated longitudinally for a 10-year period to assess the periodontal health of overdenture abutments and the effectiveness of the overdenture treatment. Of the original group, 28 patients returned for the 10-year recall. Sixty-six of the 77 overdenture abutments were present. Seven of the 11 abutment teeth extractions were because of caries and four were the result of periodontal disease. Most of the abutments have progressively lost attached tissue. Other periodontal indices remained fairly constant. Most of the patients were satisfied with the treatment even though the periodontal assessment was less than ideal.     

Treatment needs of overdenture patients in a longitudinal study: five-year results

This study evaluated the treatment needs of 44 overdenture patients who had worn their dentures for at least 5 years. There were 135 abutment teeth involved, 35 in the maxillae and 100 in the mandible. Recall rates varied from a low of 27.6% to a high of 73.7%. The attrition rate was 20.5% after 5 years. The caries rate varied from a low of 2.7% to a high of 20.6%, and periodontal treatment was required by 94% of the subjects after 5 years. Only 39.4% of the subjects required adjustments, repairs, relines, or remakes of their overdentures during this time. The study showed that the success of overdentures depended on maintaining oral hygiene at an adequate level and at least yearly recalls to maintain gingival health.     

Periodontal considerations in removable partial denture treatment: a review of the literature

PURPOSE: A critical review of the literature on the periodontal considerations in removable partial denture (RPD) treatment is presented. MATERIALS AND METHODS: A MEDLINE search was conducted for studies pertaining to the effects of RPDs on the periodontal tissues during the various phases of prosthetic treatment. The review included both in vivo and in vitro studies. RESULTS: The use of RPDs leads to detrimental qualitative and quantitative changes in plaque. There seems to be a lack of information regarding the effects of RPDs on the status of periodontally compromised abutments. A number of studies, mainly in vitro, have failed to agree on the ideal RPD design. Clinical trials have shown that if basic principles of RPD design are followed (rigid major connectors, simple design, proper base adaptation), periodontal health of the remaining dentition can be maintained. CONCLUSION: Removable partial dentures do not cause any adverse periodontal reactions, provided that preprosthetic periodontal health has been established and maintained with meticulous oral hygiene. Frequent hygiene recalls and prosthetic maintenance are essential tools to achieve a good long-term prognosis. More prospective clinical trials are needed on the effect of RPDs on the condition of periodontally involved abutment teeth.     

Periodontal problems associated with use of distal extension removable partial dentures—a matter of construction?

It is commonly assumed that a distal extension partial removable dentures rotates around the supporting rests when the saddle is occlusally loaded and that this rotation may expose the abutment teeth to a distal torque believed to be potentially harmful to their periodontal tissues. Attempts are therefore often made to counteract this effect through the denture construction. However, a review of relevant literature does not appear to substantiate an unqualified acceptance of the above mentioned assumptions, nor of the beneficial effect of special denture constructions designed to reduce the abutment loading. On the other hand, well controlled longitudinal studies seem to indicate that a favourable periodontal prognosis may be expected in such cases provided the following conditions are satisfied: Periodontal problems should be treated and an adequate oral hygiene established prior to the insertion of the denture; The periodontal health and oral hygiene should be maintained through regular recalls. During these recalls possible prosthodontic defects should be diagnosed and necessary measures implemented.     

The cantilever fixed partial denture--a literature review.

The cantilever fixed partial denture (FPD) is a restoration with one or more abutments at one end and unsupported at the other end. Forces transmitted through the cantilevered pontics can cause tilting and rotational movements of the abutments. In a cross-arch unilateral cantilever FPD, the distal cantilevered unit is subjected to comparatively less force than the contralateral posterior abutment. The unilateral lack of terminal abutments causes lateral bending forces activate peripheral inhibitory feedback reactions from the periodontal and/or temporomandibular mechanoreceptors. The greatest strain in distal cantilevered FPDs is recorded mesial to the most distal retainer because most fractures occur in this location. To improve the prognosis of the FPD cantilever, the number of abutments should be increased and the number of pontics decreased. The abutment teeth need long roots and acceptable alveolar support. Prepared abutments require adequate length and parallel axial walls. An equilibrated and harmonious occlusion is necessary, as well as exemplary oral hygiene. A cantilevered FPD with adequate periodontal support can replace any tooth in the dental arch, but is especially useful as an alternative to a removable partial denture. The cantilevered FPD requires at least two abutment teeth. The only documented exception permitting a single abutment is the replacement of a maxillary lateral incisor with the canine as an abutment. An alternative to the cantilevered FPD is the osseointegrated implant. As osseointegrated implants become more popular, the need for the tooth-supported cantilevered FPD may decline, but it will remain an alternative treatment modality.     

The efficacy of a counter-rotational powered toothbrush in the maintenance of endosseous dental implants

BACKGROUND: Although most patients with implants have lost their natural teeth because of poor oral hygiene, limited data exist to guide practitioners in their recommendations of home-care regimens for their patients' endosseous dental implants and maintenance of peri-implant soft-tissue health. The authors conducted a study to compare the home-care effectiveness of a counter-rotational powered tooth-brush with that of conventional home-care regimens. METHODS: Before starting the six-year study, the authors trained 85 clinical investigators at 32 dental research centers across the United States in gathering periodontal data. Data for 2,966 implants were entered into a centralized database. Outcomes were derived from 24-month observations of a subset of the implants studied. RESULTS: Repeated-measures analysis of the toothbrushing methods used on 2,966 implants showed that the counter-rotational powered toothbrush removed plaque significantly better than manual methods (P < .0001 Wald statistic) from all implant surfaces and at all recall intervals up to 24 months. Similar results were demonstrated for the gingival index. CONCLUSIONS: The counter-rotational powered brush appears to be well-suited for home-care regimens aimed at maintaining optimal peri-implant soft-tissue health in patients with dental implants. CLINICAL IMPLICATIONS: The importance of maintaining the health of the peri-implant tissues is well-recognized by the dental profession. The counter-rotational powered toothbrush is an effective tool in meeting the oral hygiene challenges associated with implant prosthesis maintenance.     

A 4-year clinical study on amalgam, resin composite and resin-modified glass ionomer cement restorations in overdenture abutments

Objective: To assess the performance of three different filling materials in overdenture abutment teeth.

Methods: In 49 patients amalgam, resin composite and resin-modified glass ionomer cement were used to seal the root canal orifices of 155 overdenture abutment teeth. After initial preparation of the cavities, the three restorative materials were randomly assigned to the abutment teeth using a number of balancing criteria. All patients were reviewed every six months and received the same preventive regimen. Survival was assessed at two levels: S_orig (survival of the restoration independent from eventual maintenance treatments) and S_comp (restorations survived even without maintenance treatments).

Results: The calculated overall survival percentage of the original restorations (S_orig) after four years was 63±6% (mean±SE). Calculation for the overall complete survival (S_comp) revealed a percentage survival of 57±6%. At both levels, the differences between the survivals of the investigated materials were not statistically significant (p-values>0.05). Two abutments were lost, severe caries was the reason for one extraction and another abutment tooth was extracted for periodontal reasons.

Conclusions: The results of this study did not point out a superior restorative material for the seal of root canal orifices of overdenture abutments. The distribution of failures over the patients indicates a certain patient dependency.     

Overdentures and the periodontium

Many reasons have been clarified for the retention of teeth in the oral cavity for use as overdenture abutments. The benefits afforded the patient by the preservation of the periodontium have been explained, and methods have been discussed to evaluate the zone of attached gingiva around overdenture abutments. Finally, some research has been discussed to compare some representative overdenture attachments and provide some guidelines for their use in order to more carefully preserve the periodontium.     

A two-year longitudinal study of the periodontal health status of overdenture patients

Eleven patients who were treated with maxillary or mandibular overdentures or both were recalled at 6-month intervals and studied for a period of 2 years A periodontist evaluated the periodontal health status of the abutment teeth at initial placement of the overdenture and at all subsequent recalls using standardized periodontal indices. Statistical comparisons of the data from initial examination to the 2-year recall were made to assess the periodontal health status of roots supporting overdentures.Periodic, regular recall of patients treated with overdentures is one of the most important factors in the maintenance of the integrity of the root stumps and attachment apparatus, particularly since the roots supporting mandibular overdentures are at greater risk periodontally than those supporting maxillary overdentures. Measurements of pocket depth and width of attached gingivae seem to be the most definitive criteria to determine the status of the attachment apparatus in overdenture patients. With frequent recall, overdentures appear to be a successful method of treatment.     

覆盖义齿基牙的短期临床观察

目的：对覆盖义齿的基牙进行短期临床观察。方法：对30例覆盖义齿修复患者半年及1年后回访观察。结果：下颌基牙及非银汞充填覆盖基牙更易存积菌斑及结石,并出现牙龈问题。结论：对于能保持良好口腔卫生的患者,覆盖义齿是一种较好的选择。     

The effect of controlled oral hygiene in overdenture wearers

The effect of controlled oral hygiene was studied in 40 patients treated with immediate complete overdentures in one or both jaws. Before prosthetic treatment conservative periodontal treatment was conducted with intensive instruction and motivation in oral hygiene care. Caries and periodontal status were recorded before and 2-4 weeks (day 0), 6 months, and 12 months after prosthetic treatment. However, the patients were seen more frequently for motivation and professional tooth cleaning. The material included 44 overdentures with a total of 92 abutments, with 1-4 abutments in each jaw. Before treatment the overall mean plaque index score was 1.43 +/- 0.68 and the overall mean gingival index score 1.57 +/- 0.53, and on day 0 and after 6 and 12 months the overall mean PlI score was 0.33-0.65 and the overall mean GI score 0.67-0.97. Adjacent to the abutments there was a significant reduction of the PlI and the GI scores from before treatment to day 0 and from day 0 to 6 months after prosthetic treatment (P less than 0.001). There was a significant reduction of pocket depth from day 0 to 6 months and from 6 to 12 months (P less than 0.01). The results of this study have shown that it is possible to maintain teeth as abutments for overdentures in patients with an initial poor dental status.     

Maintaining periodontal treatment

Dental maintenance, or supportive periodontal treatment (SPT), can keep the periodontium and peri-implant tissues healthy after active therapy. Patients who comply to suggested SPT fare better periodontally and keep their teeth longer. Data should be gathered by examinations, talking with patients, and reviewing personal oral hygiene. Then sub- and supra-gingival deposits should be removed. The average SPT visit should last 1 hour and should be scheduled every 3 months. Supportive periodontal treatment for patients with more advanced periodontal or peri-implant destruction should be the responsibility of the periodontist.     

The role in masseter muscle activities of functionally elicited periodontal afferents from abutment teeth under overdentures

Five overdenture wearers with a small number of remaining natural teeth were selected to evaluate the effect of the afferent input from periodontal mechanoreceptors on masseter activity in man. As a control, a full denture wearer was included. The subjects were instructed to chew a piece of gum, and/or tap their teeth. Surface EMG from the bilateral masseter muscles were recorded and analysed. When functional pressure was applied, during chewing, to the abutment teeth as well as to mucosa through the denture base, masseter activities were encouraged. Following application of anaesthesia to the periodontal membrane of the abutments, masseter activities were reduced. The duration of the silent period (SP) appearing in the EMG burst following tooth tapping was significantly increased with root support compared to mucosal support only. With topical anaesthesia of the periodontal tissues, SP duration decreased significantly. In conclusion, it has become apparent that the pressure sensibility of abutment teeth bearing functional pressure under an overdenture base is capable of facilitating masseter activity, as one of the sources of oral sensory input during mastication.     

Abutment tooth loss in patients with overdentures

BACKGROUND: Since the 1960s, the use of natural teeth as overdenture abutments has become part of accepted clinical practice. Several longitudinal studies have been conducted, but tooth loss has not been reported to be a significant problem. The aim of this study was to identify the incidence and causes of tooth loss in a prospective cohort study of subjects wearing overdentures. METHODS: The study, conducted between 1973 and 1994, evaluated 273 subjects (62.3 percent male) with a mean age of 59.6 years. RESULTS: Of the 273 subjects with 666 abutments, 74 lost 133 abutments. The most common cause of tooth loss was periodontal disease (29.3 percent) followed by periapical lesions (18.8 percent) and caries (16.5 percent). Through logistic regression, the authors found that subjects who lost teeth were more likely to have medical problems that could cause soft-tissue lesions of the oral mucosa, were less likely to use fluoride daily and were less likely to return for yearly recall visits. The authors found 22 vertical fractures in 17 subjects. Chi2 analysis revealed that overdenture teeth in the maxillary arch that were opposed by natural teeth were more likely to experience vertical fractures. CONCLUSIONS: In a study that followed up some patients for as long as 22 years, the rate of tooth loss was 20.0 percent. Many of these failures could have been prevented if patients had practiced better oral hygiene. CLINICAL IMPLICATIONS: The findings suggest that if a dentist recommends overdenture therapy, the patient needs to be examined regularly to reduce the risk of experiencing caries and periodontal disease. Also, if the abutments are in the maxilla and are opposed by natural teeth, the dentist should consider using thimble crowns to reduce the risk of vertical fractures.     

Influence of overdenture abutment tooth contour on the periodontium: a preliminary report

The effect of overdenture abutment tooth contour on plaque retention and periodontal health was evaluated in four patients over a 1-year period. Each patient had mandibular canines with similar periodontal support; however, one abutment was dome shaped while the other had 2 mm of natural peripheral root contour coronal to the ginvival margin. Eight parameters of periodontal health were measured, and no significant differences between different contours were observed after 1 year. Furthermore, irrespective of overdenture abutment contour, no deterioration in periodontal status occurred. Two subjects had significant wear of the overdenture abutments after 1 year. Further evaluation of more subjects over a longer period of time is indicated.     

Veterans Administration Cooperative Dental Implant Study — Comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part I: Methodology and comparisons between treatment groups at baseline

This study was conducted to determine whether fixed partial dentures supported by dental implants provide an acceptable alternative to conventional removable partial dentures in patients with Kennedy class I or class II edentulous conditions. The acceptability of the new treatment will be based on success rates, impact on the health of the remaining dentition, masticatory performance, patient satisfaction, and maintenance care and cost. The study was planned also to provide comparisons between two designs commonly used by dentists for fabricating removable partial dentures. The designs differed only in terms of the type of the retainer (clasp type) and tooth support (rest location).A total of 272 patients with Kennedy class I and class II edentulous conditions were assigned on a random basis to one of the treatment groups, 134 to receive a removable partial denture and 138 a fixed partial denture supported by a blade-vent implant. All of the patients were medically screened and met prespecified criteria for oral hygiene, bone support for abutment teeth, and size of the residual ridge.Thirty-four patients were eliminated from the study before completion of their treatment. An additional six patients with early implant failures were reentered in the study and followed up as a separate group. The remaining 232 patients received comprehensive dental care, including removable partial dentures for 118 and fixed partial dentures for 114 patients.A series of examinations, radiographs, masticatory performance tests, patient satisfaction, food selection questionnaires, and dietary history were completed before initiation of the treatment, 16 weeks after the insertion of an RPD or an implant, and thereafter at 6-, 18-, 36-, and 60-month intervals. In addition, patients were seen at 6-month intervals for a recall dental examination, oral prophylaxis, plaque instructions, radiographic survey of the implant, and any needed dental treatment.The randomization stratification approach produced two treatment groups with comparable age, number of remaining maxillary and mandibular teeth, type of opposing dentition, and percent of patients with Kennedy class I and class II edentulous conditions. The mean scores of bone support, tooth mobility, and sulcular depths of abutment teeth were also similar. Significant but comparable improvements in oral hygiene and sulcular depth occurred in the two groups after treatment. The periodontal health scores at the 16-week interval serve as the baseline to measure subsequent changes in periodontal health. This prospective longitudinal study with prespecified criteria for implant and removable partial denture failure should provide reliable estimates of failure rates, number and types of complications, maintenance care needs, and total costs for the two treatment modalities and the two RPD designs.     

Impact of a periodontal course on oral hygiene and gingival health among senior dental students

This survey attempted to determine the impact of the periodontal course on oral hygiene and gingival health among 50 senior dental students. The course included the following: patient motivation, instruction in oval hygiene procedures and plaque control, scaling and curellage, temporary splinting and occlusal adjustment. Without advance notice, plaque deposits were scored using the Plaque Index and gingival health was determined using the Gingival Index. The results were collected at the beginning and at the end of the periodontal course (about 2 months). The results were analyzed using the paired t-test. No improvement of either oral hygiene or gingival health was noted at the end of the periodontal course. It seems that even some dental students, who should know the direct relationship between bacterial plaque and periodontal diseases and should be better motivated than the average patient, failed to demonstrate effective oral hygiene. It is difficult to expect an improvement of patient oral hygiene, when the patients have been motivated by students who are unable to perform satisfactory personal oral hygiene themselves. It is suggested that a greater emphasis be placed on patient motivation and instruction in oral hygiene throughout the dental curriculum.