The role of the toothbrush in the abrasion process.

AIM: To evaluate the relative abrasivity of different toothbrushes both qualitatively and quantitatively. MATERIALS AND METHODS: Acrylic plates were exposed to brushing in a brushing machine with ten different toothbrushes with water alone and with a toothpaste. The results were evaluated using a profilometer after one and 6 h of brushing (corresponding to 2000 and 12,000 double strokes, respectively). A surface roughness value (Ra-value) and also a volume loss value were calculated from the profilometer measurements. These values were then compared to each other. RESULTS: The results showed that brushing with water alone caused less abrasion than when a toothpaste was added. Six-hour brushing with water caused less abrasion than 1 h with a toothpaste. The number of filaments or filament diameter influenced the results in various ways. When brushing with water, the harder toothbrush (Jordan Medium) caused more abrasion (higher Ra-value), but when adding the toothpaste, the softer toothbrush (Jordan soft) caused more abrasion after 12,000 double strokes. CONCLUSION: Besides supporting the fact that a toothpaste is needed to create a significant abrasion, this study also showed that a softer toothbrush can cause as much and in some cases more abrasion than harder ones. When conducting abrasivity studies, it is important to look at both the quantitative and qualitative aspect of abrasivity.

The use of a profilometer for both quantitative and qualitative measurements of toothpaste abrasivity.

AIM: To evaluate the abrasivity of different toothpastes both quantitatively and qualitatively with a profilometer technique and to correlate these findings to the radioactive dentin abrasivity (RDA) value. MATERIALS AND METHODS: Acrylic plates were exposed to brushing in a brushing machine with 11 different toothpastes. The results were evaluated using a profilometer. A surface roughness value (Ra-value), that is, a qualitative measurement, and also a volume value, that is, a quantitative measurement, were calculated from the profilometer results. These values were then correlated to each other and to the RDA-value. A comparison between RDA, Ra and volume measurements was performed using linear fitting procedure. RESULTS: The results showed that the correlation between RDA and Ra measurements was low (R(2) = 0.04) and also that the correlation between RDA and volume measurements was low (R(2) = 0.00002). Correlation between Ra and abraded volume was high (R(2) = 0.87). CONCLUSIONS: It is important to consider not only the RDA-value when evaluating toothpaste abrasivity. From the profilometer results both a quantitative (volume) and qualitative (roughness) measurement of the abrasivity of a toothpaste can be obtained.

Periodontal healing following reconstructive surgery: effect of guided tissue regeneration.

Clinical healing following guided tissue regeneration (GTR) in deep intrabony pockets was compared to healing following gingival flap surgery alone (GFS). 15 patients received the GTR treatment including an expanded polytetrafluoroethylene membrane. 13 other patients received the control treatment GFS. A postsurgery protocol emphasizing wound stability and infection control was used. Treatment effects were evaluated 6 months postsurgery. Mean pre-surgery probing depth for the GTR and control treatments was 7.5 +/- 1.0 and 7.7 +/- 1.5 mm, respectively. Significant probing depth reduction (3.8 +/- 1.2 and 2.9 +/- 1.1 mm), attachment level improvement (2.4 +/- 2.1 and 2.2 +/- 1.2 mm) and bone fill (2.0 +/- 2.0 and 2.4 +/- 0.9 mm) followed the GTR and control protocols, respectively (p < 0.01). Significant differences between GTR and control treatments were observed in probing depth reduction (p < 0.01) and in gingival recession increase (1.7 +/- 1.5 and 0.7 +/- 0.9 mm, respectively; p < 0.05). The results suggest that GTR procedures compared to GFS have similar clinical potential in intrabony pockets, under the present protocol.

Atypically located paramolar. Report of a rare case.

A paramolar mesial to the mandibular second molar would be predicted from the atavistic theory on phylogenetic evolution of the human dentition. The actual finding of this feature, however, appears to have been reported only once. A 4 mm long tooth was found mesial to the right mandibular second molar in a 54-yr-old Japanese female. The tooth had a ball-shaped crown, a relatively normal crown/root length ratio, and a tapering root located entirely in the gingival soft tissue.

Use of chlorhexidine chewing gum significantly reduces dental plaque formation compared to use of similar xylitol and sorbitol products.

A double-blind 3-treatment crossover design employing a 6-day trial period with out mechanical oral hygiene measures was used to compare dental plaque formation following use of chlorhexidine (CHX) acetate-, xylitol-, and sorbitol-containing chewing gum. Fourteen dental students were assigned a random ordering of the chewing gum products and received professional tooth cleaning at the start of trial periods. For each trial period, subjects were instructed to use 5 pieces of the unlabeled chewing gum daily (containing 5.0 mg CHX acetate/piece; 0.8 xylitol/piece; or 1.0 g sorbitol/piece). Two pieces of chewing gum were used following each morning and evening meal and one piece following the noon meal. The subjects were instructed to use the products for 20 minutes at each occasion. A 7-day washout-period between trial periods was used. The Turesky modification of the Quigley and Hein index was used to assess plaque formation. Differences between treatments were evaluated using a repeated measures ANOVA with Newman-Keuls multiple comparisons. The CHX-containing chewing gum showed significantly reduced plaque values (0.7 +/- 0.4) compared to the sorbitol-(2.7 +/- 0.4; P < 0.01) and xylitol-product (1.7 +/- 0.3; P < 0.01). Furthermore, the CHX-product significantly reduced plaque levels compared to the study subjects' regular plaque control routines (1.3 +/- 0.04; P < 0.05). The xylitol-product exhibited significantly lower plaque-values than the sorbitol-product (P < 0.01). Our results suggest that regular use of CHX-containing chewing gum appears useful to control dental plaque formation.