Mechanical stimulation by toothbrushing increases oxygen sufficiency in human gingivae

In-vitro comparison of two different toothbrush bristles about peri-implant sulcus penetration

OBJECTIVE

The aim of this preclinical study was to compare the ability of tapered and cylindrical bristles to penetrate the peri-implant sulcus.

METHODS

A full mandibular dental arch was reproduced in plaster cast. In site #3.6 a hollow glass cylinder was positioned simulating a 4 mm diameter implant and the gingival component was recreated by using dedicated silicone. A Bass brushing technique was performed from the vestibular side in humid environment. During it, the penetration of the bristles between the gum and the implant was recorded by mean of an optic fibre fixed inside the cylinder. The protocol included 5 toothbrushes per group and 10 tests per toothbrush, for a total of 50 assessments for each of the two groups. A scale of 5 grades for bristle penetration was defined: grade 0 (× < 2 mm), grade 1 (2 ≤ × < 3 mm), grade 2 (3 ≤ × < 4 mm), grade 3 (4 ≤ × < 5 mm) and grade 4 (5 ≤ × < 8 mm). From the video recordings the highest value of penetration was identified for each test.

RESULTS

The tapered bristles showed an 8 times greater penetration capacity (p = 0.001) in respect to the cylindrical bristles (multilevel analysis). The percentage of tests reaching depths ≥3 mm was 86% for tapered group and 28% for the cylindrical group.

CONCLUSION

This preclinical study shows a clear and superior penetration capacity of the tapered bristles in respect to traditional cylindrical ones. For tapered bristles, a potentially greater hygienic efficacy around dental implants is suggested.

Tobacco Use and Periodontal Disease-The Role of Microvascular Dysfunction

Periodontal disease consists in highly prevalent wide-ranging inflammatory conditions that affect the supporting apparatus of teeth. Tobacco use is the most important risk factor for periodontal disease as it increases disease severity and periodontal surgery complications. Tobacco use is harmful for the vasculature by causing microvascular dysfunction, which is known to negatively affect periodontal disease. To the author's knowledge this paper is the first comprehensive review on the mechanisms by which tobacco use affects oral microcirculation and impacts the pathophysiology of periodontal disease. In healthy subjects, acute nicotine administration or tobacco use (smoking/smokeless forms) increases the blood flow in the oral mucosa due to local irritation and increased blood pressure, which overcome neural- and endocrine-mediated vasoconstriction. Chronic tobacco smokers display an increased gingival microvascular density, which is attributed to an increased capillary recruitment, however, these microcirculatory units show higher tortuosity and lower caliber. These morphological changes, together with the repetitive vasoconstrictive insults, contribute to lower gingival perfusion in chronic smokers and do not completely regress upon smoking cessation. In periodontal disease there is considerable gingival inflammation and angiogenesis in non-smokers which, in chronic smokers, are considerably suppressed, in part due to local immune suppression and oxidative stress. Tobacco exposure, irrespective of the form of use, causes long-term microvascular dysfunction that increases the risk of complications due to the natural disease course or secondary therapeutic strategies.

Efficacy of non-surgical treatment accompanied by professional toothbrushing in the treatment of chronic periodontitis in patients with type 2 diabetes mellitus: a randomized controlled clinical trial

Purpose

The present study aimed to evaluate the clinical benefit of additional toothbrushing accompanying non-surgical periodontal treatment on oral and general health in patients with type 2 diabetes mellitus (T2DM).

Methods

We conducted a doubled-blind randomized controlled trial in 60 T2DM patients between June 2013 and June 2014. The patients were randomly assigned to the scaling and root planing (SRP) group; the scaling and root planing with additional toothbrushing (SRPAT) group, in which additional toothbrushing was performed by toothpick methods; or the control group. Microbiological and oral examinations were performed for up to 12 weeks following treatment. Non-surgical treatment was conducted in the experimental groups. The SRP group received scaling and root planing and the SRPAT group received additional toothbrushing with the Watanabe method once a week from the first visit through the fifth visit. The primary outcomes were changes in haemoglobin A1c (or glycated haemoglobin; HbA1c) levels, serum endotoxin levels, and interleukin-1 beta levels. Periodontal health status was measured by periodontal pocket depth, the calculus index, and bleeding on probing (BOP).

Results

Both the SRP and SRPAT groups showed improvements in periodontal health and HbA1c, but the SRPAT group showed significantly less BOP than the SRP group. Furthermore, only the SRPAT group showed a statistically significant decrease in serum endotoxin levels.

Conclusions

Non-surgical periodontal treatment was effective in improving HbA1c and serum endotoxin levels in T2DM patients. Furthermore, non-surgical treatment with additional tooth brushing had a more favourable effect on gingival bleeding management.

Trial Registration

Clinical Research Information Service Identifier: KCT000416

Comparison of semilunar coronally repositioned flap with gingival massaging using an Ayurvedic product (irimedadi taila) in the treatment of class-I gingival recession: A clinical study

AIM: To study the comparison in terms of root coverage the effect of gingival massaging using an ayurvedic product and semilunar coronally repositioned flap (SCRF) to assess the treatment outcomes in the management of Miller’s class I gingival recessions over a-6 mo period.

METHODS: The present study comprised of total of 90 sites of Miller’s class-I gingival recessions in the maxillary anteriors, the sites were divided into three groups each comprising 30 sites, Group I-were treated by massaging using a Placebo (Ghee) Group II-were treated by massaging using an ayurvedic product (irimedadi taila). Group III-were treated by SCRF. Clinical parameters assessed included recession height, recession width, probing pocket depth, width of attached gingiva, clinical attachment level and thickness of keratinized tissue. Clinical recordings were performed at baseline and 6 mo later. The results were analyzed to determine improvements in the clinical parameters. The comparison was done using Wilcoxon signed rank test. The overall differences in the clinical improvements between the three groups was done using Kruskal-Wallis test. The probability value (P-value) of less than 0.01 was considered as statistically significant.

RESULTS: Non-surgical periodontal therapy and gingival massaging improves facial gingival recessions and prevents further progression of mucogingival defects. Root coverage was achieved in both the experimental groups. The SCRF group proved to be superior in terms of all the clinical parameters.

CONCLUSION: Root coverage is significantly better with semilunar coronally repositioned flap compared with the gingival massaging technique in the treatment of shallow maxillary Miller class I gingival recession defects.

Blood flow in denture-supporting maxillary mucosa in response to simulated mastication by loading

PURPOSE

The purpose of this study was to determine the effect of number of chewing strokes on change in blood flow in denture-supporting maxillary mucosa.

METHODS

Subjects consisted of 11 healthy dentate men. Mastication was simulated by intermittent loading (10 N, 1/0.75 Hz) on a lateral area of the hard palate using a 2-cm(2) test plate. Loading duration was set at 1, 4, 8 or 12 min (80, 320, 640 or 960 chewing strokes). A non-contact laser Doppler blood flow meter was used to determine change in blood flow and time taken for recovery to 110% of the pre-loading value. Mean blood flow at pre-loading and at each duration of intermittent loading were compared using a repeated measures ANOVA (α=0.05) and the Dunnett test. Recovery times for each loading duration were compared using a one-way ANOVA (α=0.05) and the Bonferroni-test.

RESULTS

Three subjects showed no increase in mean blood flow with loading. Eight subjects consistently showed an increase in mean blood flow during intermittent loading relative to at pre-loading. Duration of loading yielded no significant difference in mean blood flow. Significant differences were observed in recovery time between at after 8 min loading and at after the other 3 loading (1, 4, and 12 min loading) durations.

CONCLUSION

Number of simulated chewing strokes showed no influence on mean blood flow during intermittent loading in denture-supporting mucosa. It did, however, affect recovery time taken for blood flow to return to its pre-loading level.

Gingival Cell Proliferation Induced by Use of a Sonic Toothbrush With Warmed Silicone Rubber Bristles

BACKGROUND

Toothbrushing promotes gingival cell proliferation, which may occur as the result of the physical stimulation of the gingiva. The present study evaluated the effects of temperature and silicone rubber bristles of a sonic toothbrush on gingival cell proliferation in dogs.

METHODS

During the 5-week experimental period, one quadrant in each of eight dogs received a different toothbrushing regimen: a manual toothbrush or a sonic toothbrush with 1) nylon, 2) silicone rubber, or 3) warmed silicone rubber bristles. The proliferative activity of gingival cells was evaluated based on expression of proliferating cell nuclear antigen (PCNA).

RESULTS

Use of the sonic toothbrushes produced a higher density of PCNA-positive and total fibroblasts than did use of a manual toothbrush. The warm silicone rubber bristles resulted in a higher density of PCNA-positive fibroblasts compared with the cooler silicone rubber bristle. The number of PCNA-positive basal cells in the junctional epithelium also increased following electric toothbrushing with warmed silicone rubber bristles.

CONCLUSIONS

The sonic toothbrush with silicone rubber bristles induced gingival fibroblast proliferation to a greater degree than a manual toothbrush. Warming the silicone rubber bristles increased their stimulatory effects on the proliferative activity of gingival cells.

Effects of toothbrushing frequency on proliferation of gingival cells and collagen synthesis

BACKGROUND

Mechanical stimulation by toothbrushing enhances proliferation of fibroblasts and junctional epithelium (JE). These changes in gingiva may depend on the interval between toothbrushing. The effects of toothbrushing frequency on proliferation of gingival fibroblasts and basal cells of JE were evaluated.

METHODS

Twelve mongrel dogs were used. Each tooth was brushed for 20 s at 1.96 N. The subepithelial connective tissue of JE was examined for proliferating cell nuclear antigen (PCNA)-positive fibroblasts and procollagen type-I C-peptide (PIP)-positive fibroblasts. JE was examined for PCNA-positive basal cells.

RESULTS

Gingiva that received brushing twice a day showed increases in the density of fibroblasts and ratio of PCNA-positive fibroblasts to total fibroblasts at 4 weeks. The ratio of PIP-positive fibroblasts increased at 8 weeks in gingiva brushed twice a day and once a day. PCNA-positive basal cell ratio increased at 4 weeks in gingiva brushed twice a day and once a day.

CONCLUSIONS

A high frequency of brushing was associated with increased numbers of PCNA-positive fibroblasts, PIP-positive fibroblasts and PCNA-positive basal cells. Gingival cell proliferation increased and reached a plateau earlier in gingiva brushed twice a day than in gingiva brushed once a day.

Spatial extent of gingival cell activation due to mechanical stimulation by toothbrushing

BACKGROUND

Mechanical stimulation by toothbrushing enhances gingival fibroblast proliferation and collagen synthesis, and reduces inflammatory cell infiltration. The aim of this study was to investigate the spatial extent of proliferation of fibroblasts and endothelial cells in dog gingiva in response to mechanical stimulation by toothbrushing.

METHODS

All maxillary fourth premolars and mandibular first molars of 6 mongrel dogs were used. Dental plaque was removed with a curet. One of each pair of bilateral teeth (in the same jaw) was assigned to the brushing group, and the corresponding tooth (opposite side) was assigned to the control group. The Bass method was used to brush the limited mesial half of the tooth at 1.96 N for 20 seconds with a fitted plastic stent. Immediately before fixation of tissue, the surface of brushed gingiva was notched to indicate the borderline between the brushed and non-brushed areas. Histometrical analyses of the sections were performed using assays for proliferating cell nuclear antigen (PCNA) and von Willebrand factor.

RESULTS

The numbers of fibroblasts and PCNA-positive fibroblasts in the subepithelial connective tissue adjacent to oral sulcular epithelium significantly increased in brushed gingiva, not only in the brushed area but also in the non-brushed area 0 to 0.5 mm from the notch. Increased numbers of vascular endothelial cells were observed only in the brushed area.

CONCLUSION

The effect of mechanical stimulation by toothbrushing on gingival cell proliferation was not observed more than 0.5 mm from the brushed area. These results indicate that effective activation of gingival cell proliferation requires mechanical stimulation of gingiva in all areas.

Toothbrushing and gingival recession

AIM

To review the hypothesis that toothbrushing leads to gingival recession. Gingival recession develops due to anatomical and pathological factors. The prevalence of recession is dependent on the age and characteristic of the population because it usually presents in individuals with periodontal disease or those who practise zealous or improper oral hygiene methods. Gingival trauma and gingival abrasion from toothbrushing is thought to progress directly to gingival recession. Case studies documenting recession from toothbrush trauma are speculative. Short-term studies suggest that gingival trauma and gingival abrasion may result from toothbrushing, but the direct relationship between traumatic home care and gingival recession is inconclusive. Long-term studies remain elusive or do not support the development of recession following toothbrushing. Nevertheless, tooth abrasion may be an integral part in the aetiology of recession. Toothbrush abrasion also may cause wear at the cemento-enamel junction resulting in the destruction of the supporting periodontium leading to recession.

The effect of duration and force of mechanical toothbrushing stimulation on proliferative activity of the junctional epithelium

BACKGROUND

Gingival bleeding is frequently accompanied by an ulcerated epithelium, with repair depending on the proliferative activity of the epithelial cells. The present study examined the proliferative activity of the junctional epithelium (JE) under several different methods of toothbrushing stimulation.

METHODS

Twelve dogs were used in this 3-week experiment. Prior to the experiment, all teeth underwent daily removal of plaque and calculus using a scaler. Teeth were then divided into quadrants: 9 teeth in 3 quadrants (test, 3 per quadrant) were mechanically stimulated by toothbrushing for various time intervals (10, 20, or 40 seconds) and at various forces (100, 200, or 250 gf). The 3 teeth in the fourth quadrant served as controls. The proliferative activity of the basal cells of the junctional epithelium was evaluated for expression of proliferating cell nuclear antigen (PCNA). The numbers of PCNA-positive basal cells and total basal cells were counted, and the width of the junctional epithelium was measured.

RESULTS

Toothbrushing force significantly affected the PCNA-positive basal cell ratio (P < 0.05). The 200 g toothbrushing force produced the highest PCNA-positive basal cell ratio, which was significantly higher than that using the 100 g force (P < 0.05).

CONCLUSION

In junctional epithelium stimulated with a toothbrush, the PCNA-positive basal cell ratio is more sensitive to toothbrushing force than to duration.

Toothbrushing promotes gingival fibroblast proliferation more effectively than removal of dental plaque

OBJECTIVES

Removal of dental plaque is an essential element of periodontal treatment. However, there have also been studies of the effects of the mechanical stimulation provided by toothbrushing on gingival host-defense mechanisms. The aim of the study was to evaluate the effects of toothbrushing on gingival fibroblast proliferation in dogs over time, compared to effects of plaque removal without brushing.

METHODS

The mouths of six mongrel dogs were divided into four quadrants: two for daily toothbrushing, and two for daily plaque removal with a curette. After 1, 3 and 5 weeks of treatment, histometrical analyses were performed to assess inflammatory cell infiltration, proliferating cell nuclear antigen (PCNA)-positive fibroblasts, procollagen type I-positive fibroblasts in the subepithelial connective tissue of junctional epithelium.

RESULTS

Toothbrushing increased the number of PCNA-positive fibroblasts in the first week, increased the number of type I procollagen-positive fibroblasts at the fifth week, and reduced inflammatory cell infiltration at the third week.

CONCLUSION

These findings suggest that mechanically stimulated fibroblasts begin proliferating within a week, and this cell division results in an increased number of fibroblasts at the third week. It takes 5 weeks before differences in collagen synthesis between brushing and plaque removal areas are detectable.

Effect of mechanical toothbrush stimulation on gingival microcirculatory functions in inflamed gingiva of dogs

The effect of mechanical toothbrush stimulation on gingival microcirculatory functions was examined with and without removal of supragingival plaque in inflamed gingiva of 6 dogs. After removal of the ligatures, 4 treatment modalities: mechanical stimulation by vibration (MS), removal of supragingival plaque (PR), combination (MS+PR) and no treatment (NT), were administered to each quadrant for 2 weeks. Both quadrants with plaque removal showed a marked decrease in the gingival index score, while slight and moderate decreases were observed in NT and MS quadrants, respectively. Changes in gingival crevicular fluid flow, pocket oxygen tension and hemoglobin oxygen saturation in the gingiva were significant in the MS, PR and MS+PR quadrants. Significant treatment-by-time effects were found for all of the parameters of microcirculatory function between NT and MS quadrants, and gingival crevicular fluid flow between PR and MS+PR quadrants, respectively. These findings suggest that mechanical stimulation with a toothbrush may offer an additional benefit to gingival microcirculatory functions in inflamed gingiva.

Comparisons of modalities of mechanical stimulation with a toothbrush on improvement of oxygen sufficiency in dog gingiva

Mechanical stimulation with a toothbrush was applied to each quadrant of 10 dogs at a force of 200 g for 10 s using following modalities: vibration at attached gingiva, pressurization at attached gingiva, vibration at marginal gingiva and no treatment as a control. Hemoglobin oxygen saturation (SO2) in the gingiva was measured by non-invasive tissue reflectance spectrophotometry. Simultaneously, oxygen tension (pO2) in gingival tissue was monitored with an oxygen microelectrode. Both SO2 and pO2 increased within 10-20 min after stimulation and then slowly returned to the initial level at all treatment sites. The response was most prominent after vibration at attached gingiva. SO2 and pO2 increased by 12% and 42%, respectively, and significant increase continued for 75-85 min. Response after vibration at marginal gingiva was moderate in pO2 and transient in SO2. Pressurization at attached gingiva caused moderate response in SO2, but the increase in pO2 was slight. Control showed little change in both indices. These results suggest that vibration with a toothbrush at attached gingiva may cause a maximal response in improving oxygen sufficiency to gingival tissue.

Effect of mechanical stimulation by tooth brushing on oxygen tension in dog gingiva

To determine oxygen tension (pO2) in gingival tissue, an oxygen micro-electrode with a membrane-coated Pt needle was inserted into the gingiva of 12 dogs. Teeth were brushed using a modified Bass technique for 10 s under 200 g pressure. pO2 increased and reached a maximum 15 min after brushing, then gradually returned to the baseline. A significant increase in pO2 persisted for approx. 1 h. These findings suggest that short-term stimulation by tooth brushing increases oxygen tension in the gingiva.