Effect of different frequencies of preventive maintenance treatment on periodontal conditions. 5-Year observations in general dentistry patients.

The protocol for this study was designed to evaluate the effects of supportive recall treatments provided with different frequencies, viz. at 3-, 6-, 12- and 18-month intervals. The subjects for the study were recruited from patients attending a public, general dentistry clinic. Prior to baseline, the subjects were given necessary dental treatments to provide a proper baseline for the study. Baseline, intermittent and final recordings included scores of dental plaque, bleeding on probing, probing depth and probing attachment level. Results were evaluated statistically by intergroup comparisons of changes for the various parameters from baseline to final examination after 5 years. The analyses showed some advantage to shorter recall intervals for plaque and bleeding scores. Although not statistically significant, there was a trend suggesting some rebound of sites > or =6 mm deep at the end of the study for the 18-month group, but not for the other groups. Similarly, there was a trend that the 18-month group showed a higher percentage of buccal/lingual furcation sites with attachment loss > or = 1.0 mm than the other groups. Apart from these trends, the analyses failed to demonstrate differences between the groups for either changes of probing depths or probing attachment levels. The negative observations included identification of individuals with 'disease progression' in the various groups, using a series of arbitrary definitions for this parameter. The results of this trial suggest that recall intervals extended to a year may be acceptable for the purpose of reducing periodontal disease progression in individuals with a history of limited susceptibility to the disease.

Scores of plaque, bleeding, suppuration and probing depth to predict probing attachment loss. 5 years of observation following nonsurgical periodontal therapy.

The purpose of the present study was to determine the diagnostic value of clinical scores of supragingival plaque, bleeding, suppuration and probing depth to predict probing attachment loss in patients on maintenance following nonsurgical periodontal therapy. Non-molar teeth in 39 subjects were monitored and the above scores were repeatedly obtained throughout 5 years of observation following initial treatment. Probing attachment loss between 0-60 months was determined by a combination of linear regression analysis and end-point analysis. The results revealed that all the investigated scores were associated with probing attachment loss. This association was demonstrated by improved diagnostic predictability along with increased frequency or magnitude of the various scores. Also, the diagnostic predictability improved with increase in length of time for recording of the scores. The diagnostic predictability of either accumulated plaque scores and accumulated bleeding scores reached a maximum of about 30%. Residual probing depth greater than or equal to 7 mm reached a predictability of around 50% and increase in probing depth greater than or equal to 1.0 mm reached about 80% after 60 months. Thus, of the clinical scores investigated, increase in probing depth was found to be most valuable in predicting probing attachment loss.

4-year observations of basic periodontal therapy.

A total of 2214 sites from incisors, cuspids, and premolars were studied in 46 adult periodontitis patients following treatment consisting of plaque control and root debridement. The periodontal status at 24 months was used as baseline for observations during the subsequent 24-48 month interval which included 4 recall visits for debridement at the 24-, 30-, 36-, and 42-month time points. The data were analyzed for pooled groups of sites of different probing depth at 24 months: less than or equal to 3.5 mm, 4.0-6.5 mm, and greater than or equal to 7.0 mm. The results showed little change during the 24-48 month interval in mean scores for bleeding on probing, probing depth, and probing attachment level for all 3 groups of sites. Individual sites with probing attachment loss during the 24-48 month period were identified. The frequency of such sites was similar, irrespective of 24-month probing depth. The sites identified with probing attachment loss during the 24-48 month interval generally differed in location from those identified as having probing attachment loss during the preceeding 0-24 month period. Often, the loss of probing attachment during the 24-48 month interval seemed to be a reversal of a prior gain in probing attachment during the 0-24 month interval. This study in non-molar teeth of subjects with generally good level of compliance failed to demonstrate that sites with deeper probing depth were more difficult to maintain than shallower sites.

Effect of nonsurgical periodontal therapy (VIII). Probing attachment changes related to clinical characteristics.

Individual sites with gain and loss of probing attachment were identified amongst 1688 proximal sites in non-molar teeth from 49 patients monitored for 24 months following oral hygiene instruction and root debridement. The distribution of sites with gain and loss of probing attachment was studied within each of the 49 subjects, for each of the 10 different tooth types treated, for teeth with and without root canal fillings, for mesial and distal surfaces, and for surfaces with and without the presence of root concavity/furcation involvement. Similarly, sites with gain and loss were related to the following measurements of the severity of the initial lesion: initial probing depth, radiographic bone score, depth of radiographic intraosseous defect, and radiographically widened periodontal ligament. The analyses indicated that subjects with a higher proportion of sites with probing attachment gain tended to have a lower proportion of sites with probing attachment loss. Sites with deep initial probing depth demonstrated a high incidence of gain and a low incidence of loss of probing attachment. All other investigated characteristics showed weak or no association with probing attachment change following therapy. This report indicates that the 24-month outcome of plaque control and root debridement in proximal surfaces of non-molar teeth is not compromised by the severity of the initial soft tissue or bony lesion.

Longitudinal observation of "unattached," mobile gingival areas.

Facial gingival surfaces over cuspids and bicuspids in 20 patients were monitored for 5 years to evaluate the importance of attached gingiva in the maintenance of a stable periodontium. 43 surfaces "at risk" were compared to 36 "non-risk" surfaces within these patients. Surfaces "at risk" had to meet the following 3 criteria as established by both of 2 independent examiners: width of keratinized gingiva less than or equal to 1.0 mm; absence of attached gingiva; mobility of the gingival margin. During the 5 years of observation, "non-risk" surfaces showed a trend toward decrease in mean width of keratinized gingiva, while this measurement remained unchanged for the surfaces "at risk" Probing depths remained unaltered for both groups. A trend toward gingival recession and loss of probing attachment was observed for both "risk" and "non-risk" surfaces. Thus, this study failed to demonstrate that "unattached" and mobile facial gingival surfaces are more susceptible to periodontal breakdown than "attached" surfaces.

Effect of nonsurgical periodontal therapy. VII. Bleeding, suppuration and probing depth in sites with probing attachment loss.

Incisors, cuspids and premolars in 49 patients with advanced chronic periodontitis were treated with initial, nonsurgical periodontal therapy. The results were monitored by probing attachment level measurements for 6 sites of each tooth every 3rd month during a period of 24 months. Amongst sites with initial probing depth greater than or equal to 4.0 mm, sites with probing attachment loss were identified using regression analysis. Scores for plaque, bleeding, suppuration on probing and probing depth, obtained for these sites during the 24-month study, were analyzed to determine whether any of the scores could be used diagnostically as an indicator of probing attachment loss. Diagnostic sensitivity and predictability were calculated for different levels of each of the scores. The results showed that sites with probing attachment loss were more frequent for sites with high scores for plaque, bleeding, residual probing depth and suppuration than in sites with low scores. However, the diagnostic sensitivity and predictability of these clinical indicators was generally low. Thus, records of plaque, bleeding, suppuration and probing depth do not obviate the need for probing attachment level measurements for identification of sites with probing attachment loss following initial, nonsurgical periodontal therapy.

Effect of non-surgical periodontal therapy. VI. Localization of sites with probing attachment loss.

Incisors, cuspids and premolars in 49 patients with advanced chronic periodontitis were treated with initial, non-surgical periodontal therapy. The results were monitored by probing attachment level measurements at 6 sites of each tooth every 3rd month during a period of 24 months. A series of 9 probing attachment level measurements for each site was subjected to linear regression analysis. The slope of the regression line, the projected probing attachment loss during the 24-month interval (delta y) and the probability level of the slope were calculated for each site. 2 groups of sites with probing attachment loss were identified: group 1: sites with delta y greater than 1.5 mm and p less than 0.05; group 2: sites with delta y greater than 1.0 mm and p less than 0.05. Group 1 included 120 sites (5%) and group 2 included 265 sites (10%) of the total of 2532 available sites. In both groups, probing attachment loss was more frequently noticed for sites with an initial probing depth less than or equal to 3.5 mm than for sites with initial probing depth greater than or equal to 7.0 mm. The finding that the majority of sites with probing, attachment loss was found amongst initially shallow or moderately deep lesions may indicate attachment loss due to trauma associated with therapy rather than loss as a result of a continuing, inflammatory disease process.

Effect of implants on healing of experimental furcation defects in dogs.

The present study was performed to find out whether implants placed around periodontally involved teeth during reconstructive surgery would support replaced flaps and prolong gingival coverage of the treated root surfaces facilitating new attachment. Through-and-through furcation defects were made in the mandibular second, third, and fourth premolars of 10 beagle dogs. Bone was surgically removed from the furcation and from the circumference of each tooth to a level 3 to 4 mm apical to the cementoenamel junction. Steel wires were passed through the furcations and ligated to enhance plaque formation. At 6 weeks, the wires were removed. At 12 weeks, during reconstructive surgery, 4 dogs received implants of autogenous intraoral cancellous bone, 2 of autogenous iliac cancellous bone and marrow, 2 of Proplast, and 2 of Avitene. The results demonstrated that none of 12 teeth implanted with Avitene or Proplast showed new attachment. Only 2 of 6 teeth implanted with autogenous iliac bone showed new attachment, combined with extensive root resorption and ankylosis. Of 12 teeth implanted with autogenous intraoral bone, 6 showed new attachment. Our findings suggest that flap support by intraoral cancellous bone implants may facilitate new attachment. A more predictable technique, however, needs to be developed.

Effect of nonsurgical periodontal therapy. V. Patterns of probing attachment loss in non-responding sites.

Incisors, cuspids and premolars in 33 patients with advanced chronic periodontitis were treated by plaque control and 1 single episode of supra- and subgingival debridement. The results were monitored by probing attachment level measurements for 6 sites of each tooth every 3rd month during a period of 24 months. A total of 1368 sites were observed. From these were selected 280 "non-responding" sites showing 1.0 mm or more loss of probing attachment at 24 months compared to baseline. Scatter diagrams of the sequence of 9 probing attachment recordings obtained during the 24-month study were produced for each of these 280 sites. Study of these scatter diagrams resulted in identification of 7 different patterns of probing attachment change over time. A linear pattern of gradual loss of probing attachment throughout the 24-month observation period was found for 73% of the non-responding sites. Of the less frequently seen patterns, 3 approximated a linear course and 3 were non-linear. Linear analysis of regression as a statistical method to determine attachment loss for individual sites seems to be suitable for sites with linear patterns and for sites approximating a linear pattern. The insensitivity of regression analysis in non-linear patterns may be acceptable if a cautious analysis is warranted.

Effect of non-surgical periodontal therapy (IV). Operator variability.

Healing following non-surgical periodontal therapy was studied and the results of instrumentation performed by 6 operators compared. Incisors, cuspids and premolars with periodontal pockets up to 11 mm deep in 20 patients were treated by plaque control and a single episode of supra- and subgingival debridement. A split-mouth approach was used to compare the participating therapists. The effects of the therapy were monitored using changes in plaque score, bleeding score, probing pocket depth and probing attachment level. Marked improvement, similar to that seen in previous studies evaluating non-surgical therapy was noted during the initial 6-9 months. No further changes of the recorded parameters could be observed during the rest of the 24-month observation period. Differences between sites treated by the various operators were negligible. Thus, it appears, that deep periodontal pockets in incisors, cuspids and premolars may be successfully treated by plaque control and 1 episode of instrumentation and that operator variability may be limited.

Reproducibility of probing attachment level measurements.

The reproducibility of probing attachment level measurements in incisors, cuspids and premolars was studied in 2 groups of patients with severely advanced periodontal disease. The results showed that approximately 90% of the recordings could be reproduced within within +/- 1.0 mm difference. This was found for intra-examiner as well as inter-examiner comparisons of 2 examiners. Measurements using onlay margins for reference point demonstrated somewhat less variability than the use of cemento-enamel junction for reference. The level of reproducibility varied notably between patients and was improved following non-surgical periodontal therapy. Also, the reproducibility varied significantly between tooth types, tooth surfaces and probing pocket depths. It was concluded that in clinical studies, the evaluation of the healing response of individual lesions should include consideration of the variability of repeated measurements for each of the investigated tooth sites.

Effect of nonsurgical periodontal therapy. III. Single versus repeated instrumentation.

Healing events following nonsurgical periodontal therapy were studied, comparing the effect of a single initial instrumentation to the effect of 3 instrumentations, each separated by 3 months. Incisors, cuspids and premolars with periodontal pockets up to 11 mm deep in 13 patients were treated by plaque control and supra- and subgingival debridement using ultrasonic instruments. A split mouth approach was used to compare the 2 frequencies of instrumentation. The results were evaluated by recording of plaque scores, bleeding on probing, probing pocket depths and probing attachment levels. A gradual and marked improvement of the periodontal conditions took place during the initial 9 months following start of therapy. During the remaining 15 months of the 24-month experimental period no further changes of the recorded parameters were noted. No differences in results could be observed when comparing the effects of a single versus repeated instrumentation. Thus, it appears that deep periodontal pockets in incisors, cuspids and premolars may be successfully treated by plaque control and 1 episode of instrumentation. The results also suggest that recurrence of disease due to subgingival recolonization by microorganisms during the healing phase may not be a major clinical problem.

Effect of nonsurgical periodontal therapy. II. Severely advanced periodontitis.

Healing events following nonsurgical periodontal therapy in patients with periodontal pockets up to 12 mm deep were investigated. Incisors, cuspids and premolars in 16 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 recording of plaque scores, bleeding on probing, probing pocket depths and probing attachment levels. Minimal change in gingival conditions occurred during the initial 3 months of experimentation, which were utilized for plaque control measures alone. Subsequent to instrumentation and during the following 9-month period, a gradual and marked improvement of periodontal conditions took place. During the remaining 12 months of the 24-month experimental period no further changes of the recorded parameters were noted. No differences in results could be observed when comparing hand versus ultrasonic instrumentation, or when comparing the results of 2 different operators. Initially, a total of 305 sites demonstrated probing pocket depths greater than or equal to 7 mm. At the 24-month examination 43 such sites remained. The results indicate that there is no certain magnitude of initial probing pocket depth where nonsurgical periodontal therapy is no longer effective.

Healing after treatment of periodontal intraosseous defects. I. Comparative study of clinical methods.

Four clinical methods to evaluate healing after reconstructive therapy of intraosseous periodontal defects were compared: 1. probing attachment level, 2. probing bone level, 3. entry/re-entry bone height measurements, 4. radiographic bone height determinations. Thirteen patients with a total of 33 defects volunteered for the study. It was found that the depth of the lesions recorded by the various methods showed differences which seem to relate to the varying nature of the methods. On the average, the periodontal probe penetrated 0.8 mm deeper during probing for bone level than during probing for attachment level and another 0.3 mm deeper after denudation of the lesions during entry/re-entry. The average gain of periodontal support following treatment was approximately 1.4 mm as recorded by probing attachment level, probing bone level and entry/re-entry bone height determinations, respectively. A high degree of correlation was found between all three probing methods when the changes following therapy for the individual sites were compared (r = 0.85, 0.75 and 0.81, respectively). Radiographic bone height showed lower degrees of correlation with all three probing parameters (r = 0.45, 0.46 and 0.47, respectively).

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

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 tongue brushing on formation of dental plaque.

The effect of tongue brushing on formation of dental plaque was studied in two groups of dental hygiene students. In one of the groups plaque formation during a 4-day period of no oral hygiene procedures was compared to a 4-day period of tongue brushing as the only hygiene procedure. In the other group tongue brushing as an adjunct to tooth brushing was evaluated on plaque formation during 7-day periods of partially ineffective tooth brushing. Both experiments failed to show any effect of the tongue brushing on plaque formation.