M. Addy

Dentine hypersensitivity : the distribution of recession, sensitivity and plaque

Abstract The features of dentine hypersensitivity have been presented largely in descriptive form and there is only limited information on the intraoral distribution of the condition. Additionally, there have been conflicting reports of both high and low plaque accumulation at sites of hypersensitivity. This study investigates the distribution of recession, sensitivity and plaque in a group of 92 patients diagnosed as suffering moderate to severe dentine hypersensitivity affecting several teeth. The group was relatively homogeneous and there was no significant variation in recession, sensitivity or plaque scores between subjects. Tooth number (1–28) highly significantly influenced all parameters. In three-way analyses of variance to identify the effects of jaw, side and tooth number in a segment (1–7) almost all parameters were significantly influenced, however: 1. 1. The dominant factors affecting degree of recession were side and tooth number. 2. 2. The dominant factor affecting sensitivity was side. 3. 3. The dominant factors affecting buccal plaque were side and tooth number. 4. 4. The dominant factor affecting lingual plaque was jaw. Two- and three-way interactions were, for the most part, also significant. The correlation matrix revealed significant positive correlations for recession with sensitivity and significant negative correlations for recession and sensitivity with buccal plaque. The findings indicate that the intraoral distribution of recession, sensitivity and plaque in this selected population is complex, being partly fitted by a main-effects model, and suggest that tooth cleaning is one of several major factors which influence the occurrence and distribution of dentine hypersensitivity.

Triclosan and sodium lauryl sulphate mouthrinses. (II). Effects of 4-day plaque regrowth.

Toothpastes have been shown to exert some plaque inhibitory effects probably due to the action of detergents such as sodium lauryl sulphate (SLS). Recently the antimicrobial, triclosan, has been added to experimental and commercial toothpaste products to enhance activity against plaque. There is, however, little information as to the plaque inhibitory effects alone of ingredients such as SLS and triclosan. This investigation compared the effects on 4-day plaque regrowth of a 1% SLS, 0.2% triclosan and 0.2% chlorhexidine rinse with a 0.9% saline rinse. The study was single blind, latin square, four-period crossover design, balanced for residual effects and employing 16 healthy dentate volunteers. During each period, normal oral hygiene ceased and plaque regrowth from a zero baseline was measured by score and area after 2 x daily rinses with 10 ml volumes of each rinse. Washout was a minimum of 60 h. Plaque scores and areas were significantly lower with chlorhexidine than the other preparations and significantly higher with saline. There were no significant differences between SLS and triclosan. The results were essentially consistent with the similar substantivity of SLS and triclosan demonstrated from the salivary bacterial count investigation. Taste acceptability may, however, explain the small reverse trends noted between the two studies. It is concluded that both SLS and triclosan would individually confer plaque inhibitory properties to toothpaste formulations. However, when combined in a single formulation, their effects may not be additive.

Aetiological, predisposing and environmental factors in dentine hypersensitivity

If the hydrodynamic theory of stimulus transmission across dentine is valid, sensitive dentine has tubules open at the surface and patent to the pulp. Direct and indirect evidence supports this supposition. Factors that result in dentine exposure remove the covering enamel or periodontal tissues (gingival recession). Epidemiological and clinical data for the distribution of exposed cervical dentine indicate that chronic trauma from physical and chemical factors is the most significant aetiological factor. Brushing with a toothpaste may not open dentinal tubules. It is more likely that toothpaste ingredients, when brushed on dentine, would create a smear layer. Exposure of tubules by erosion is probably the major initiator of sensitivity. An increase in our understanding of the aetiological factors involved in dentine hypersensitivity is essential if a sound approach to its management is to evolve. Such information could emanate from epidemiological studies, clinical investigations and laboratory experiments.

The effect of social class on the prevalence of caries, plaque, gingivitis and pocketing in 11–12-year-old children in South Wales

Abstract The effect of social class on the dental disease status of a group of 11–12-year-old schoolchildren in South Wales is presented. There were a number of differences between the social classes for the DMFT, DMFS and DFS indices, with social class I having significantly less caries experience than the others. These differences, however, were largely confined to the boys. There appeared to be no significant difference in reported toothbrushing frequency between the social classes but the children from the lower social classes admitted spending significantly more on sweets per week. The plaque and gingival bleeding scores showed an overall trend to increase from social class I through to social class V. The girls, in particular, showed progressively increasing and significantly different mean plaque and gingivitis scores.

The use of acrylic to compare the abrasivitand stain removal properties of toothpastes

Abstract The aim of this study was to compare the abrasivity and stain removal properties of toothpastes using acrylic. Acrylic blocks were exposed to 2·5 × 104 and 5·0 × 104 brush strokes with a number of toothpastes. Abrasion measurements were made using a surfometer. Percentage stain removal with time was recorded from specimens stained by chlorhexidine and tea soaking. Pre- and post-treatment optical densities were recorded spectrophotometrically. Products were applied to specimens as slurries alone or with brushing. Depth of abrasion was ⩽ 10 μm for most toothpastes (5 × 104 strokes). For two desensitising toothpastes the depth reached > 40 μm. Stain removal was dependant on the duration of brushing, but at 1 min., ranged from 97% to 50% for toothpastes and 45% for a brush and water. Slurries of toothpaste also variably removed stain; effects at 1 min. ranged from 90% to levels similar to water, namely 5%. It is concluded that the model is a simple and reproducible method to compare oral hygiene products and allows chemical stain removal properties to be ascertained and divorced from abrasion and chemical erosion.

Clinical study investigating abrasive effects of three toothpastes and water in an in situ model

OBJECTIVESnThis in situ study compared the abrasive effect of repeated brushings (over 10 days) of a low relative abrasive dentine (RDA) toothpaste with moderate and high relative abrasive dentine (RDA) toothpastes, on human dentine in situ.nnnMATERIALS AND METHODSnThe study design was single centre, single blind, randomized, split mouth, two period, four-treatment cross-over, in situ study in 20 healthy subjects. Subjects wore bi-lateral lower buccal appliances each fitted with four dentine sections with treatment applied with a power toothbrush, during each 10 day study period. Samples were measured at baseline, day 5 and day 10 by contact profilometry, and baseline and day 10 with non-contact profilometry.nnnRESULTSnNineteen subjects were included in the efficacy analysis. Results as measured by contact and non-contact profilometry from brushing with the moderate RDA paste and high RDA paste showed significantly (p<0.0001) more abrasion to dentine than brushing with the low RDA paste or water after 10 days. Dentine loss following tooth brushing with the low RDA paste was not significantly different from brushing with water, after 10 days.nnnCONCLUSIONSnThe methodology successfully showed clear differentiation between the amount of dentine lost following toothbrushing with the low RDA paste compared to the moderate or high RDA pastes. Dentine loss following brushing with the low RDA paste showed a comparable degree of abrasion to brushing with water.

Determination of minimum inhibitory concentrations of commercial toothpastes using an agar dilution method

Abstract Commercial toothpastes have been suggested as a possible means of conveying antimicrobials to the mouth with the desired aim of reducing plaque accumulation and thus improving gingival health. This study measured the ability of a number of commercial toothpastes to inhibit oral microorganisms by determining minimum inhibitory concentrations (MICs) of the toothpastes, using an agar dilution method. Although not as effective as chlorhexidine, the MICs obtained for most of the toothpastes were low enough to expect some antimicrobial activity in the mouth following a normal toothbrushing regimen. Whether the magnitude of the effect in vivo would be of clinical value to gingival health has yet to be determined.

Does gingivitis lead to periodontitis in young adults

It has been assumed that poor oral hygiene predisposes to gingivitis with progression to periodontitis and tooth loss. However, a high prevalence of gingivitis occurs in some populations in which severe periodontitis is rare. To assess whether gingivitis is a reliable predictor of periodontitis, we compared the periodontal health of tea pickers and university students aged between 18 and 30 in Indonesia. Oral hygiene and gingival health was significantly better in students than in tea pickers. However, the prevalence and the severity of chronic periodontitis were similar in the two groups. Our findings suggest that gingivitis is a poor predictor of periodontitis in subjects younger than 30 years. Attempts to prevent periodontitis in young adults through antigingivitis measures such as plaque control may be unsuccessful.

Factors influencing the initiation of carious lesions in specific tooth surfaces over a 4-year period in children betweem the ages of 11–12 years and 15–16 years

An analysis of factors influencing the initiation of carious lesions on specific tooth surfaces over a 4-year period in children between the ages of 11-12 years and 15-16 years is presented. Approximately 1000 children, resident in the County of South Glamorgan, Wales, were assessed for caries status and oral cleanliness in 1980 when aged 11-12 years and again in 1984 when aged 15-16 years. On both occasions, the children completed detailed questionnaires on dental health-related topics. Surfaces which were sound when the children were 11-12 years were identified and subsequently awarded a score of zero if they remained sound at 15-16 years or a score of one if they had developed carious lesions or had been filled. For each child, a mean mouth caries initiation score was computed for specific groups of surfaces, namely pit and fissure surfaces in posterior teeth, approximal surfaces in posterior teeth, buccal and lingual smooth surfaces of all teeth and approximal surfaces of anterior teeth. One-way analysis of variance and multiple regression techniques revealed that a number of factors had a significant influence on the initiation of caries. The factors and their level of significance varied between the surfaces. However, relatively little (less than 6 per cent) of the total variance in caries initiation score could be explained by the identified factors. Overall, more lesions developed in pit and fissure surfaces in posterior teeth than in the other surfaces included in the analyses.

Clinical in situ study investigating abrasive effects of two commercially available toothpastes

The aim of this study was to determine if the abrasive effect on dentine of two commercially available toothpastes, known to vary in their in vitro abrasive levels, can be differentiated in an in situ model after 10 days, assessed by contact profilometry. This was a single centre, single blind, randomized, split mouth, two treatment, in situ study, in 34 healthy subjects, evaluating the abrasive effects of two marketed desensitizing toothpastes, (Colgate Sensitive Multi Protection toothpaste - C; Sensodyne Total Protection - S). Subjects wore bi-lateral, lower buccal appliances, each fitted with four dentine sections which were power brushed three times a day with the treatment regimen. Each subject received two toothpaste treatments for 10 days during the treatment period. Samples were measured at baseline and day 10 by contact and non-contact profilometry and day 5 by contact profilometry. Thirty-four subjects were included in the efficacy analysis. Results from contact profilometry showed statistically significant (P < 0.0001) dentine loss compared to baseline at day 5 and 10 for both pastes. At each time point, C showed statistically significantly greater dentine loss than S, P < 0.0001. After 10 days treatment, the difference in dentine loss between the pastes was 1.4 microm. The non-contact profilometry data showed similar trends. After 10 days of treatment, C showed statistically significantly greater dentine loss than S, with treatment difference of 0.9 microm, P = 0.0057. The methodology used has successfully differentiated between the abrasivity of the two pastes in respect of dentine surface loss over time in an in situ environment.