Tooth wear in patients treated with HIV anti-retroviral therapy.

BACKGROUND: The objective of this study was to elucidate the relationship between HIV anti-retroviral therapy and tooth wear. METHODS: Assessment of tooth wear was conducted both with a survey questionnaire and clinical assessment at Russell Street Dental Clinic in Portland, Oregon. The survey questionnaire comprised of questions on study participant's gender, age, HIV status, current medications, awareness of tooth grinding or clenching, jaw soreness, tooth or gum soreness, and frequency of headaches. For the clinical evaluation, a dental provider recorded the degree of wear on each tooth using a scale of 0-3. An individual tooth-wear index was used to rank patients with regard to incisal and occlusal wear. Data analysis included descriptive analysis, tests of association and regression analysis using SPSS V.24. RESULTS: The study sample involved 93 patients (HIV + ve = 60, HIV-ve = 33) with age range of 20-90 yrs. (mean = 49 yrs., s.d = 13.3). 92 and 67% participants of the HIV + ve and HIV-ve groups, respectively, presented with tooth wear. The mean tooth wear index was higher in HIV + ve patients than HIV-ve patients (8.2 vs. 7.8), however, this difference was not statistically significant (p > 0.05). A significant, positive correlation was found between HIV presence and tooth wear index, after accounting for age (B = 0.71, p < 0.05). The number of years on anti-retroviral therapy alone was positively correlated with tooth wear index (R2 = 0.116, p < 0.05). After controlling for age, years of anti-retroviral therapy use was positively correlated with tooth wear index (B = 0.047, p > 0.05). CONCLUSIONS: The findings from this study suggest that HIV + ve patients, who are on anti-retroviral therapy have significant tooth wear, although more studies with larger sample size are needed to confirm this. There is a critical need to initiate a dialogue with medical providers about tooth wear as a possible side effect of antiretroviral therapy and to introduce appropriate preventive measures.

Effect of Remineralizing Gels on Microhardness, Color and Wear Susceptibility of Bleached Enamel.

OBJECTIVES:: To evaluate the effect of a remineralizing gel combining fluoride and calcium silicate/phosphate or a sodium fluoride gel on bleached enamel microhardness, color, and wear susceptibility. METHODS AND MATERIALS:: Two hundred forty bovine enamel-dentin samples were prepared. Baseline analysis of Knoop microhardness, color coordinates (L*a*b*), and surface profile were performed. According to the baseline microhardness values, specimens were stratified into six groups (n=40): NC (negative control)-no treatment; BL (positive control)-bleaching with 40% hydrogen peroxide gel (Opalescence Boost, Ultradent); BL/Rs-bleaching + application of calcium silicate/phosphate gel (Regenerate Serum, Unilever - Rs); Rs/BL-Rs + bleaching; Rs/BL/Rs-Rs + bleaching + Rs; and BL/F-bleaching + 2% sodium fluoride gel. After the treatment described for each group, color change (ΔE) and microhardness were evaluated again. To evaluate abrasion susceptibility, samples were randomly divided into two subgroups, according to the toothpaste used (Cp-Close Up or Rt-Regenerate), and underwent 100,000 brushing strokes. The profile of each sample was evaluated and the mean wear calculated. The data were analyzed by ANOVA and Tukey tests. RESULTS:: All bleached groups showed a significant reduction of microhardness in relation to the negative control. The groups treated with remineralizing gels showed a significantly higher microhardness and less wear than the positive control, although nonsignificant differences were observed among them. Nonsignificant differences in ΔE were found among bleached groups. The groups brushed with Regenerate toothpaste showed significantly less wear than those brushed with Close Up toothpaste. CONCLUSIONS:: The remineralizing gels did not interfere with bleaching efficacy. However, all the treatments minimized the surface hardness reduction caused by the bleaching procedure and enamel loss after abrasion. Regenerate toothpaste resulted in less enamel abrasion.

Enamel wear by antagonistic restorative materials under erosive conditions.

OBJECTIVES: This study aimed to analyse loss of enamel worn against composite, leucite glass ceramic or enamel antagonists under non-erosive and alternating or simultanuous erosive-attritive conditions. MATERIALS AND METHODS: Flat human enamel specimens were loaded (1 Hz, 300 g loading weight, each subgroup n = 12) with antagonists made from a hybrid-composite (Z250, 3 M Espe), a nano-composite (Filtek Supreme XTE, 3 M Espe), leucite glass ceramic (IPS Empress CAD LT, Ivoclar Vivadent) or enamel. Specimens were either submitted to mechanical loading in mineral solution (60 s) or to loading under alternating or simultaneous erosive conditions. For alternating erosion-attrition, specimens were eroded by citric acid (pH 2.6, 60 s) and then loaded with the respective antagonist for 60s. For simultaneous erosion-attrition, specimens were loaded with the respective antagonist while being immersed in citric acid (pH 2.6, 60 s). After each cycle, specimens were stored in water for 1 h. After 18 cycles, enamel loss was calculated profilometrically and statistically analysed by two-way ANOVA and Tukey's post-hoc tests (p < 0.05). RESULTS: Enamel loss (µm, mean ± standard deviation) was significantly highest for simultaneous erosion-attrition (ceramic 9.4 ± 1.1, hybrid-composite 8.3 ± 0.7, nano-composite 7.8 ± 1.2, enamel 7.4 ± 0.8) followed by alternating erosion-attrition (ceramic 3.5 ± 0.5, hybrid-composite 2.1 ± 0.8, nano-composite 1.0 ± 0.2, enamel 2.5 ± 0.7) and attrition in mineral solution (ceramic 0.5 ± 0.3, hybrid composite 0.3 ± 0.1, nano composite 0.1 ± 0.2, enamel 0.1 ± 0.1). Ceramic antagonists resulted in significantly higher loss than the remaining antagonistic materials when alternating or simultaneous erosion-attrition was performed. CONCLUSION: Erosive conditions had a massive impact on enamel worn against different antagonistic materials, with simultaneous erosive-attritive conditions being more detrimental than alternating erosive-attritive conditions. CLINICAL RELEVANCE: Enamel wear by antagonistic restorative materials is significantly influenced by erosive conditions.

In vitro effects of acid challenge on incisal/occlusal cupping/cratering.

STATEMENT OF PROBLEM: The cause of occlusal/incisal cupping/cratering (depressed dentin surrounded by elevated rims of enamel) has been postulated to be primarily the effect of acid on exposed dentin. It is hypothesized that abrasion, bruxism, attrition, and stress-corrosion may play a secondary role in lesion formation. The primary cause and sequence of occlusal/incisal cupping/cratering remain scientifically controversial. PURPOSE: The purpose of this in vitro study was to determine the effects of acid on human enamel, mantle dentin, and peritubular dentin in the creation of incisal/occlusal cupping/cratering. This study was designed to visually illustrate the role of acid in the formation of cupping/cratering. MATERIAL AND METHODS: A soft compact toothbrush was tested using both high relative dentin abrasivity (RDA)- and low-RDA dentifrices and water only (nonabrasive) on extracted human teeth. Seventeen specimens of 4 teeth each (68 teeth) were subjected to horizontal brushing with a 1:1 dentifrice-to-water slurry or water only. Twelve of these 17 specimens, a total of 48 teeth, were subjected to acid challenge. Each of these 12 specimens were brushed for 500 strokes after each acid challenge for a total of 150000 strokes and 300 acid immersions. Half the specimens were acid challenged for 5 minutes and the other half for 10 minutes between brushings. RESULTS: No visible loss of tooth structure was noted in the control specimens brushed in water only. The control specimens brushed in a 1:1 slurry of toothpaste/water demonstrated incisal/occlusal cupping/cratering. The acid-challenged specimens brushed in water only demonstrated enamel and peritubular dentin loss with elevated rims and/or plateaus of mantle dentin, the opposite of occlusal/incisal cupping/cratering. All specimens brushed with the higher abrasive dentifrice demonstrated visible wear of enamel, mantle, and peritubular dentin, culminating in occlusal/incisal cupping/cratering. Surprisingly, those acid-challenged specimens brushed with the lower abrasive toothpaste demonstrated visible wear of the enamel and peritubular dentin, resulting in elevated rims and/or plateaus of mantle dentin. CONCLUSIONS: Acid affects both the enamel and the mineralized component of dentin. This study demonstrated that incisal/occlusal cupping/cratering occurring in worn dentition can be caused by the use of dentifrice alone. Acid challenge affects the inorganic components of tooth structure but not the organic components and so does not cause the dentinal cupping/cratering of the incisal/occlusal surfaces of the human dentition.

Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel.

UNLABELLED: Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. OBJECTIVE: The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. MATERIAL AND METHODS: Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10), each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL) or diode laser/violet LED (VHL) (experimental): Control (C); 35% Total Blanc Office (TBO35HL); 35% Lase Peroxide Sensy (LPS35HL); 25% Lase Peroxide Sensy II (LPS25HL); 15% Lase Peroxide Lite (LPL15HL); and 10% hydrogen peroxide (experimental) (EXP10VHL). pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (µm). ANOVA and Tukey´s tests were applied (α=0.05). RESULTS: The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. CONCLUSION: There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups.

Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10), each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL) or diode laser/violet LED (VHL) (experimental): Control (C); 35% Total Blanc Office (TBO35HL); 35% Lase Peroxide Sensy (LPS35HL); 25% Lase Peroxide Sensy II (LPS25HL); 15% Lase Peroxide Lite (LPL15HL); and 10% hydrogen peroxide (experimental) (EXP10VHL). pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm). ANOVA and Tukey´s tests were applied (α=0.05). Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups.

The impact of the new scene drug "crystal meth" on oral health: a case-control study.

OBJECTIVE: The use of methamphetamine (MA), a highly addictive stimulant, is rapidly increasing, with MA being widely abused as the scene drug "Crystal Meth" (CM). CM has been associated with severe oral health effects, resulting in so-called "Meth mouth". This term appeared for the first time in 2005 in the literature and describes the final complex of symptoms including rampant caries, periodontal diseases and excessive tooth wear. The aim of this study was to investigate the effects of chronic CM abuse on teeth and intraoral tissue with respect to potential symptoms of Meth mouth. MATERIALS AND METHODS: In cooperation with two centres for addiction medicine, we performed clinical intraoral investigations in 100 chronic CM users and 100 matched-pair controls. We undertook a caries and periodontal examination by using the clinical parameters DMF-T/DMF-S, bleeding on probing index (BOP) and periodontal screening index (PSI) and tested individual oral hygiene by using approximal space plaque index (API). All clinical data were analysed by the t test for independent samples. RESULTS: We found significantly larger numbers of caries (p < 0.001) and higher levels of gingival bleeding (p < 0.001) and periodontal disease (p < 0.001) among CM users. Oral hygiene was significantly lower in CM users (p < 0.024). CONCLUSION: Chronic CM use can lead to extensive potential damage within the intraoral cavity. When CM is used over a long period of time and in the absence of treatment, clinical symptoms in terms of Meth mouth syndrome cannot be excluded. CLINICAL RELEVANCE: Based on our results, we recommend a specific prevention and therapeutic concept including educational campaigns for MA users and specialized dental care for CM patients.

Choice of toothpaste for the elderly: an in vitro study.

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey's test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

Clinical and laboratory surface finishing procedures for zirconia on opposing human enamel wear: A laboratory study.

AIM: To investigate the effect of laboratory and clinical finishing procedures for zirconia on antagonistic enamel wear. MATERIALS AND METHODS: Forty-eight yttria-tetragonal partially stabilised zirconia (Y-TZP) specimens were prepared and divided into four groups according to their surface preparation: laboratory polished (LP); laboratory polished and glazed (G); clinically adjusted (CA); and clinically adjusted and repolished (CAR). Enamel opposing enamel was used as a control. Pre-testing surface roughness for each group was determined using contact profilometry. Two-body wear resistance tests were conducted using a masticatory simulator. Enamel specimens were subjected to 120,000 cycles in distilled water (frequency 1.6 Hz, loading force of 49 N). Volumetric and vertical enamel losses were measured by superimposition of pre- and post-testing images using a three-dimensional laser scanner and software analysis. Scanning electron microscopy was used for qualitative surface analysis of pre- and post-testing zirconia and enamel surfaces. One-way ANOVA and multiple comparisons with Bonferroni corrections were used for statistical analysis at a significance level of α=0.05. RESULTS: There was no statistical difference in volumetric and vertical enamel loss between CAR, G and LP. CAR produced statistically significantly less volumetric enamel loss compared with CA and control, and statistically significantly less vertical enamel loss compared with CA. Volumetric and vertical enamel loss were highly correlated in all groups. CONCLUSIONS: Enamel wear by clinically ground zirconia is comparable to that of opposing enamel surfaces and greater than clinically repolished zirconia. Repolishing of zirconia restorations following clinical adjustment with diamond burs is effective in reducing antagonistic enamel wear.

The relationship between incisal/occlusal wear, dentine hypersensitivity and time after the last acid exposure in vivo.

OBJECTIVE: The aim of this study was to investigate the relationship between tooth wear and dentine hypersensitivity on occlusal/incisal tooth surfaces and the time since dietary acid consumption. METHOD: 350 subjects were recruited from hospital and general practice in SE England aged 19-34 years old. The severity of tooth wear and dentine hypersensitivity was calculated on occlusal/incisal tooth surfaces per subject using Basic Erosive Wear Examination (BEWE) and Cumulative Hypersensitivity Index (CHI) scores respectively at each appointment. The CHI score relied on evaporative stimuli applied to each occlusal/incisal tooth surface. The subjects were also asked about the time since their last acidic food or drink consumption. RESULT: Tooth wear was recorded in 93% (n=327) of subjects and dentine hypersensitivity was recorded in 56% (n=196) of subjects. A positive statistically significant relationship existed between the severity of tooth wear and severity of dentine hypersensitivity recorded using BEWE and CHI on occlusal/incisal tooth surfaces (p<0.01). Dentine hypersensitivity and tooth wear were correlated with consumption of acidic beverages (p<0.01). The severity of dentine hypersensitivity on occlusal/incisal tooth surfaces was associated with the time since the subject's last acidic food consumption (p<0.01). Among those subjects who consumed an acidic beverage within 60min of their appointment, 87.2% (n=130) had dentine hypersensitivity. Among subjects who had consumed the acidic beverage more than 1h previously, the prevalence of dentine hypersensitivity was 12.8% (n=19). CONCLUSION: The severity of tooth wear on occlusal/incisal tooth surfaces is associated with the dentine hypersensitivity severity. Subjects who consume dietary acidic beverages more recently are more likely to have dentine hypersensitivity. CLINICAL SIGNIFICANCE: Occlusal tooth surfaces suffer erosive, attritive and abrasive tooth wear. Tooth wear is important in the aetiology of dentine hypersensitivity on these surfaces. Dentine hypersensitivity is more likely initiated if subjects consume acidic beverages more recently. This supports clinically the episodic nature of dentine hypersensitivity caused predominately by active erosive tooth wear.

Choice of toothpaste for the elderly: an in vitro study

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey’s test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments.

OBJECTIVE: To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products. MATERIAL AND METHODS: Fifty (50) fragments of bovine enamel (15 mm × 5 mm) were randomly assigned to five groups (n=10) according to the product utilized: G1 (control)= silicone polisher (TDV), G2= 37% phosphoric acid (3M/ESPE) + pumice stone (SS White), G3= Micropol (DMC Equipment), G4= Opalustre (Ultradent) and G5= Whiteness RM (FGM Dental Products). Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p≤0.05) which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p≤0.05). RESULTS: Means and standard deviations of roughness and wear (µm) after all the promoted stages were: G1=7.26(1.81)/13.16(2.67), G2=2.02(0.62)/37.44(3.33), G3=1.81(0.91)/34.93(6.92), G4=1.92(0.29)/38.42(0.65) and G5=1.98(0.53)/33.45(2.66). At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion. CONCLUSIONS: In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear.

Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments

ABSTRACT Objective: To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products. Material and Methods: Fifty (50) fragments of bovine enamel (15 mm × 5 mm) were randomly assigned to five groups (n=10) according to the product utilized: G1 (control)= silicone polisher (TDV), G2= 37% phosphoric acid (3M/ESPE) + pumice stone (SS White), G3= Micropol (DMC Equipment), G4= Opalustre (Ultradent) and G5= Whiteness RM (FGM Dental Products). Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p≤0.05) which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p≤0.05). Results: Means and standard deviations of roughness and wear (µm) after all the promoted stages were: G1=7.26(1.81)/13.16(2.67), G2=2.02(0.62)/37.44(3.33), G3=1.81(0.91)/34.93(6.92), G4=1.92(0.29)/38.42(0.65) and G5=1.98(0.53)/33.45(2.66). At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion. Conclusions: In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear. .

Potential effects of tooth-brushing on human dentin wear following exposure to acidic soft drinks.

This study used scanning electron microscopy and atomic force microscopy to examine the short-term potential effects of brushing time and the start-time of tooth-brushing after demineralization on primary dentin wear in vitro. Thirty-six noncarious primary central incisors were assigned to 12 experimental groups. Exposure to cola drinks was used to initiate the demineralization process. Three brushing times (5, 15 and 30 s) and four start-times of brushing (0, 30, 60 and 120 min) after an erosive attack were used for the abrasion process. Tooth-brushing the softened dentin surface led to increases in the open tubular fraction and microstructural changes on the dentin surface. Brushing immediately after exposure to cola resulted in the greatest irreversible dentin loss, whereas brushing 60 or 120 min after pretreatment resulted in the least irreversible dentin loss. However, brushing time had no effect on the irreversible loss of dentin wear. Based on these experimental results, tooth-brushing should be performed at least 60 min after consuming a cola drink to achieve the desired tooth cleaning and avoid the introduction of surface lesions on dentin.