Gingival bleeding in an experimental clinical trial design

Clinical efficacy of a new cetylpyridinium chloride-hyaluronic acid-based mouthrinse compared to chlorhexidine and placebo mouthrinses-A 21-day randomized clinical trial

OBJECTIVE

To compare the effectiveness of a novel cetylpyridinium chloride (CPC)-hyaluronic acid (HA)-based mouthrinse with chlorhexidine (CHX) and placebo mouthrinses in preventing plaque and gingivitis. The secondary outcomes were calculus, extrinsic stains, oral malodour and occurrence of adverse events.

METHODS

A 21-day randomized, double-blind, three-arm parallel study with random allocation of young dental students to any of the three mouthrinse groups. Thorough prophylaxis was done at baseline followed by a baseline examination for oral malodour, extrinsic stains, calculus, gingivitis and plaque by a single examiner. All the subjects used the allocated mouthrinse twice daily for 21 days and were examined again at the end of the experimental period. They were also interviewed for adverse events. Change in the scores of clinical indices was calculated and compared between the groups.

RESULTS

A total of 75 subjects were included and completed the experiment. There was a significant difference for change in plaque index scores between the groups (P = .015); subjects in the placebo group experienced higher levels of plaque accumulation than the other groups. Teeth staining increased in the CHX (P < .001) and placebo groups (P = .002), but not in CPC-HA users (P = .573). No significant differences were found between the three experimental groups for change in the gingival index (P = .08), calculus scores (P = .494), oral malodour (P = .870) and reporting of adverse events (P = .249).

CONCLUSIONS

CPC-HA and CHX had similar effectiveness in preventing plaque accumulation, while no differences were observed between the mouthrinses for preventing gingivitis. Dental staining was caused by CHX and the placebo mouthrinses but not by CPC-HA mouthrinse.

Effect of pre-experimental maintenance care duration on the development of gingivitis in a partial mouth experimental gingivitis model

The present study was designed to evaluate if different periods of supervised oral hygiene prior to the experimental gingivitis trial have an effect on the amount of inflammation which develops in the 'toothshield' model. Two groups were compared. One group (Group A) was supervised over a 5-month period before experimental gingivitis. Six months later Group A participated in a second trial, this time receiving only a 1-month pretrial. A second group (Group B) which served as a control was supervised over a pre-trial period of 1-month prior to the start of the experimental gingivitis phase. During the pre-trial period all subjects undertook a regime of vigorous oral hygiene which included polishing of the test quadrant in the upper jaw and supervised subgingival brushing, interdental taping or the use of toothpicks. The presence of plaque and bleeding were assessed. Following the pre-trial period all plaque control measures in the experimental area were prevented during oral hygiene periods by the temporary placement of soft, loosely fitting vinyl toothshield guard. During this period they accumulated plaque rapidly and developed a generalized gingivitis. The results of this study indicate that, irrespective of the length of the pretrial period, subjects by group develop a comparable mean level of plaque and gingival bleeding. However, the extent to which gingivitis develops differs among individuals and was for a number of subjects not consistent. Therefore, in designing an experimental gingivitis trial care should be taken to include a sufficient number of subjects to account for individual variation.

A stereomicroscopic and immunohistochemical study of vasculature in gingiva bleeding after probing

This study investigated the stereomicroscopic appearance of gingival sulcular surfaces and the histologic alterations of subepithelial vasculature of gingiva bleeding after probing. Sixty-four pairs of gingival biopsies from 49 patients were obtained and the results of stereomicroscopically visible vasculature were observed in half of the specimens. The number of biopsies showing that the vasculature of bleeding gingiva was significantly greater than those of non-bleeding gingiva. The immunohistochemical marker UEA-1 was used to identify endothelial cells on the vascular walls of 34 gingival biopsies from 15 patients. Following stereomicroscopic examination, tissue preparation with routine and UEA-1 stainings was performed. Volumetric and numerical analyses of vasculature in 6 divided portions of subepithelial connective tissue were measured. The results showed that significantly greater numbers of UEA-1 staining vessels were found within the apico-superficial portion of bleeding gingiva than those of non-bleeding gingiva. However, there was no specific correlation between the UEA-1 positive vessels within gingival tissue and stereomicroscopic visibility of vasculature on the surface appearance. It is suggested that increased vascularity in gingiva may be responsible for bleeding on clinical probing.

Short-term effect of Keyes' approach to periodontal therapy compared with modified Widman flap surgery

Keyes' method of non-surgical therapy was compared with modified Widman flap surgery in 9 patients with symmetrical periodontal disease. Following an initial oral hygiene programme, baseline measurements were recorded and paired contralateral areas were subjected randomly to the 2 techniques. 42 teeth receiving surgery were compared with 40 treated by Keyes' method. 6 sites per tooth were scored immediately prior to therapy and 3 months later, using a constant force probe with onlays. Consistent data were recorded for the 6 separate sites, which showed no baseline difference between treatments, slightly greater recession with surgery at 3 months, but no difference between treatments in probing depth and attachment levels. Mean data for individual patients showed similar consistency. Probing depth in deep sites was reduced slightly more with surgery, and there were no differences in bleeding on probing at 3 months. Both techniques gave marked improvements in health. Surprisingly, only 2 subjects preferred Keyes' technique of mechanical therapy, 6 preferred surgery, and 1 had no preference.

Experimental gingivitis in relation to susceptibility to periodontal disease. (I.) Clinical observations

The aim of the present study was to investigate the rate of development of experimentally-induced gingival inflammation in relation to the susceptibility to periodontal disease. By selection according to age, a younger (25-39 years) and an older (45-54 years) age group, with a comparable reduced but healthy periodontium, was selected. This equal amount of periodontal breakdown may suggest that the younger age group represented individuals with a relatively higher degree of susceptibility to periodontal disease. At the start of the experiment, each patient was instructed to abstain from oral hygiene procedures in 1 quadrant of the mouth for a period of 18 days. Results showed that all subjects developed signs of gingival inflammation. Regarding the development of redness and swelling, no differences could be assessed between the 2 age groups. However, analysis of the bleeding scores revealed that bleeding on probing developed more rapidly in the younger age group. It was concluded that those patients who have suffered from a more rapid form of periodontal disease also develop inflammation, in terms of bleeding on probing, more rapidly.

Gingival bleeding after chlorhexidine mouthrinses

During a clinical trial for evaluating the antiplaque effect of two flavoured chlorhexidine rinses, the observation was made that bleeding after gentle massage of the gingival margin occurred more often after chemical than after mechanical oral hygiene measures. In order to ascertain the validity of this unexpected observation, the same dental students participated in a repetition of the trial 18 months later. The results of the two trials indicate that gingival bleeding after gentle massage of the margin with the side of a periodontal probe actually occurs more frequently after rinsing twice daily with a 0.2% aqueous chlorhexidine solution for 1 week than after meticulous mechanical oral hygiene measures during an equally long time period. The average frequency of bleeding, in per cent of all examined gingival units, ranged from 1.3% after mechanical cleaning of the teeth to 5.4% after rinsing with chlorhexidine for 1 week. Neither the frequency of bleeding nor the difference between mechanical and chemical plaque control were considered to be of clinical significance. Further microbiological and histological studies are being conducted in an attempt to clarify the reason for the observed bleeding tendency.

An overview of periodontal surgical procedures

It is obvious from the foregoing that there are many technical approaches to periodontal surgery. The mere presence of a periodontal pocket of a cerain depth as the major indicator for surgery is not as steadfast as once believed. Other criteria such as hemorrhage and exudate must also be used in evaluating the need for surgery. The decision on which approach to use remains with the therapist and the individual situation which he/she is faced. However, in the past decade it has become increasingly clear that the need for so-called more advanced surgical procedures is not as important to the control of periodontal diseases as was once thought. Regardless, it is also clear that some form of surgical intervention, as defined by this paper, is still necessary to interrupt the sequence of events that make up the pathogenesis of periodontal disease that leads to eventual tooth loss. This paper has reviewed and evaluated some of the current procedures available to the therapist in the surgical approach to therapy.

The effect of locally released oxygen on the development of plaque and gingivitis in man

An experimental gingivitis study was designed to test the effect of a 5-min twice daily oxygen application on the development of plaque and onset of gingivitis. A method for the local application of medical grade oxygen to the upper anterior teeth was developed, with the lower anterior teeth used as controls. Fourteen periodontally healthy dental students of average age 21.9 years participated in the study. There was no significant effect of oxygen on plaque formation, crevicular fluid flow, or the number of gingival bleeding sites. Experimental and control gingival segments exhibited bleeding on probing at an average of 6.6 days after cessation of mechanical plaque control, much earlier than reported in other experimental gingivitis studies.

Influence of probing force on the reproducibility of bleeding tendency measurements

Three groups of seven patients were selected on the basis of about 50% loss of alveolar bone support in some part of the mouth. All patients received initial treatment consisting of plaque control and removal of subgingival deposits. In the first group of patients 95 interproximal pockets were measured three times by one examiner using the pressure probe employing a constant probing force of 0.75 N. Bleeding or lack of bleeding from a pocket was sought for up to 30 seconds after probing. Results show that a time interval of 15 minutes between reexamination procedures is enough to prevent an increased bleeding index caused by repeated probing. In the second group of patients, 98 interproximal pockets were measured three times with a Merritt-B probe (Hu-Friedy), each time by a different examiner. In the third group of patients, 102 interproximal pockets were measured three times with a pressure probe, each time by a different examiner. The same three examiners were involved. In both groups presence or absence of bleeding from a pocket was recorded. Results show a proportion of interexaminer agreement among three examiners of 0.40 with the Merritt-B probe and 0.71 with the pressure probe. It is concluded that a constant probing force of 0.75 N does contribute to more reproducible bleeding tendency measurements.

Variability of gingival bleeding in experimental gingivitis trials

Gingival bleeding is a difficult parameter to assess in experimental trials. The Confirmed Bleeding Day was recently developed as a measurement for this purpose. It was observed that considerable variations existed between the measurements made in a pilot study and an experimental trial, and these variations were subjected to a statistical analysis. The reasons for the variations are discussed, and recommendations made for the design of experimental trials involving gingival bleeding.