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Sunil Mankar,1 Bennett T Amaechi,1 Kannan Kanthaiah,1 Nahid Iftikhar,1 Amos C Obiefuna2 1Department of Comprehensive Dentistry, University of Texas Health San Antonio, San Antonio, Texas, USA; 2ANCOSTAT Statistical Consulting, San Antonio, Texas, USACorrespondence: Bennett T Amaechi, Department of Comprehensive Dentistry, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas, 78229-3900, USA, Tel +1 210 567 3185, Email amaechi@uthscsa.eduPurpose: This study investigated the influence of nanohydroxyapatite-containing (nanoHAP) lozenge on plaque pH following sucrose intake.Patients and Methods: Sixteen adult subjects were enrolled in this double-blind crossover study composed of four interventions: (1) 10% w/v sucrose solution, (2) 10% w/v sorbitol solution, (3) nanoHAP lozenge, and (4) 10% w/v sucrose solution challenge followed by nanoHAP lozenge. Following the determination of each subject’s resting plaque pH, the pH was measured at different time intervals from 3 to 30 minutes from the start of intervention, with 7 days interval between the applications of different interventions. The data were analyzed using the analysis of variance and Tukey’s test (α < 0.05).Results: While sorbitol produces no change in plaque pH, nanoHAP-lozenge increased the plaque pH from a baseline of 7.0 ± 0.3 (mean ± sd) to 7.8 ± 0.2 (mean ± sd) within 30 minutes. Sucrose lowered the plaque pH from a baseline of 7.0 ± 0.4 (mean ± sd) to the lowest minimum of 5.1 ± 0.1 (mean ± sd) at the 7th minute, rising above the critical pH of enamel dissolution (5.5) at 12th minute and the baseline pH in more than 30 minutes. With lozenge intervention following sucrose challenge, plaque pH rose to 5.5 in 8 min, and to the baseline pH in 24 min. The cH area (Hydrogen ion concentration area) produced by sucrose (1.82 sq. units) was significantly (p < 0.05) greater than that produced when sucrose was challenged with lozenge (0.48 sq. units).Conclusion: Nanohydroxyapatite-containing lozenge increased plaque pH, reduced plaque pH drop in the presence of sucrose, and facilitated the rapid recovery of plaque pH after sucrose intake.Keywords: dental plaque, nanohydroxyapatite, demineralization, buffering, lozenge

Bennett Tochukwu Amaechi,1 Sahar Mohseni,1 Andrew M Dillow,1 Mackenzie H Cvelich,2 Ana Stevanovic,3 Alphonsus Igoche Abah,1 Fatemeh Movaghari Pour,1 Rayane Farah,1 Yuko Kataoka,1 Maria Camila Restrepo,1 Dennis Zhang,4 Leonora Ethleen Leigh,4 Joel Basilan4 1Department of Comprehensive Dentistry, University of Texas Health San Antonio, San Antonio, TX, USA; 2Department of Developmental Dentistry, University of Texas Health San Antonio, San Antonio, TX, USA; 3Kleberg Advanced Microscopy Center, University of Texas at San Antonio, San Antonio, TX, USA; 4Research & Development – Oral Care, BASF Corporation, Tarrytown, NY, USACorrespondence: Bennett Tochukwu Amaechi, Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA, Tel +1 210 567 3185, Email amaechi@uthscsa.eduPurpose: Erosive tooth wear (ETW) is characterized by subsurface demineralization and tooth substance loss with crater formation. Remineralization of subsurface demineralization has previously been demonstrated; however, repair of the eroded surface is still under investigation. This study investigated the effectiveness of mouthwashes containing hydrolyzed wheat protein (HWP) in repairing ETW through promotion of organized crystal growth.Methods: Enamel Erosion was created on 210 enamel blocks by 10-minute demineralization in 1% Citric Acid (pH 3.5). Then, blocks were randomly assigned to seven groups (30/group); (A) 0.2% HWP, B) 1% HWP, (C) 2% HWP, (D) 1% HWP + 0.05% NaF, (E) Listerine™ mouthwash, (F) 0.02% NaF Crest™ Pro-health mouthwash and (G) artificial saliva (AS) only. Groups were subjected to daily pH-cycling consisting of one 5-minute erosive challenge with citric acid, three 1-minute mouthwash treatment periods, and then storage in AS for the rest of the time for 28 days. Treatment effects were assessed using SEM-EDX. Statistical analysis was by ANOVA and Tukey’s multiple comparison.Results: In groups exposed to HWP-containing mouthwashes, there was growth of fiber-like crystals that increased in packing density in a dose-dependent manner (0.2%, 1%, 2%) on the eroded enamel surfaces, with increased calcium and phosphate contents on the treated surfaces. The non-HWP-containing groups had the eroded surfaces covered by structureless deposit layer firmly attached to the surface.Conclusion: Treating eroded enamel surface with HWP-containing mouthwash resulted in repair of the damaged tissue by formation of a protective layer of crystal deposits within and on the eroded enamel tissue.Keywords: hydrolyzed wheat protein, Enameguard, erosive tooth wear, acid erosion, erosion repair, remineralization

Bennett Tochukwu Amaechi,1 Thais Santiago Phillips,1 Veronica Evans,1 Chidera Precious Ugwokaegbe,2 Minh Nguyet Luong,1 Linda Oge Okoye,3 Frederic Meyer,4 Joachim Enax4 1Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health San Antonio, San Antonio, TX, 78229-3900, USA; 2Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA; 3Department of Restorative Dentistry, Faculty of Dentistry, College of Medicine, University of Nigeria, Enugu, Nigeria; 4Research Department, Dr. Kurt Wolff GmbH & Co. KG, Bielefeld, GermanyCorrespondence: Bennett Tochukwu AmaechiDepartment of Comprehensive Dentistry, School of Dentistry, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USATel +1 210 567 3185Email amaechi@uthscsa.eduPurpose: The effectiveness of a hydroxyapatite (HAP) toothpaste and a fluoride toothpaste in preventing root tissue demineralization (root caries) was compared using an established pH-cycling caries model.Materials and Methods: Sixty dentin blocks were produced from the root tissue of extracted human teeth and were assigned to 3 test groups (n=20/group): 10% hydroxyapatite toothpaste (HAP), 1450 ppm fluoride toothpaste (fluoride), and artificial saliva (artsaliva). Early root caries lesions were developed in each sample by 7-day demineralization using a pH-cycling caries model. The daily cyclic treatment regimen consists of two 2-minute toothpaste-slurry treatment periods, one 6-hour acid challenge using acidified gel (pH 4.5), and then storage in remineralizing solution (artsaliva) for the rest of the time. Demineralization was assessed as the amount of mineral loss (∆z) using transverse microradiography (TMR). Pairwise comparisons (between treatments) were performed using analysis of variance (ANOVA), and then Tukey’s HSD for multiple comparisons. All p-values are considered significant if p< 0.05.Results: Both ANOVA and Tukey’s HSD indicated no significant (ANOVA; n=20) difference in mean ∆z among the groups, with least ∆z (±Sd) in the HAP (1117± 366) compared to fluoride (1392± 334) and artsaliva (1406± 223). Relative to control, HAP and fluoride inhibited root demineralization by 21% and 6%, respectively.Conclusion: Within the limit of the present study, the tested toothpaste containing 10% HAP is an effective root caries control toothpaste. Toothpaste containing 10% HAP was slightly more effective in preventing tooth demineralization than 1450 ppm fluoride provided as sodium fluoride. Thus, this study shows that HAP toothpastes can serve as an effective alternative to fluoride toothpastes for root caries management.Keywords: hydroxyapatite, fluoride, pH cycling, artificial saliva, demineralization, toothpaste

Priscila Christiane Suzy Liporoni,1,2 Wan Zaripah Wan Bakar,3 Rayssa Ferreira Zanatta,1 Glaucia Maria Ambrosano,4 Flávio Henrique Baggio Aguiar,5 Bennett T Amaechi2 1Department of Restorative Dentistry, University of Taubaté, Taubaté, SP, Brazil; 2Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA; 3School of Dental Sciences, Universiti Sains Malaysia Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia; 4Department of Community Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil; 5Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP, BrazilCorrespondence: Flávio Henrique Baggio AguiarUniversity of Campinas - Piracicaba Dental School, Av. Limeira, 901, bairro Areao Piracicaba, SP, BrazilEmail baguiar@unicamp.brPurpose: The aim of this study was to evaluate the effect of erosive/abrasive cycles and two different levels of abrasiveness of dentifrices over enamel and dentin subjected to bleaching.Methods: Enamel and dentin bovine specimens were prepared and submitted to an at-home bleaching treatment using 9.5% hydrogen peroxide gel, which was applied daily (30 min/14 days). Concomitant with bleaching, an erosive cycle was performed using citric acid (0.3%, pH 3.8, 5 mins, 3×/day), followed by immersions in artificial saliva for remineralization (30 mins). Abrasion was done with two (high and low abrasiveness) dentifrices (2×/day, 120 seconds) after the first and third erosive immersion each day. Enamel and dentin softening were assessed by microhardness and erosive tooth wear by optical profilometry. Data were submitted to repeated measures ANOVA, followed by the Tukey’s test with a significance level of 5%.Results: For the enamel and considering the erosive-abrasive cycle, significant differences were found between the groups tested, the bleaching, and the abrasiveness of the dentifrice tested; however, the final microhardness values were significantly lower than the initial ones. For dentin, differences were found between the eroded/abrasion and the non-eroded/abrasion groups, with the former presenting lower microhardness values compared with the latter. In addition, bleaching decreased the microhardness values only for the highly abrasive dentifrice, and the final values were lower than for the initial ones for all tested groups.Conclusion: The use of high and low abrasiveness dentifrices during bleaching and concomitant with erosion/abrasion cycles is more harmful to dentin than to enamel.Clinical Relevance: Although bleaching is considered a conservative treatment, it can cause deleterious effects to dental hard tissue. The association of an at-home bleaching technique with erosion and high- or low- abrasive dentifrices harms dentin more than enamel.Keywords: bleaching, enamel, dentin, erosion, wear

There is little information in the literature on the relationship among the frequency of carbohydrate consumption, the use of fluoride toothpaste, and enamel demineralization. The aim of this investigation was to compare the extent of demineralization of enamel slabs in situ, with a sugar-based solution, consumed in constant amounts but with various frequencies in subjects both with and without the use of fluoride (F) toothpaste. Eight subjects wore removable mandibular appliances carrying an enamel slab cut from white-spot lesions. The subjects were required to drink 500 mL of a 120-gm/L sugar solution either once, 3, 5, 7, or 10 times/day for 30 sec on each occasion, for a period of 5 days while brushing their teeth twice daily with either a F (1450 ppm NaF) or a F-free toothpaste. Mineral analysis revealed that when the subjects used a F toothpaste, net demineralization was evident only with the seven- and 10-times/day regime (ns). When F-free toothpaste was used, statistically significant demineralization was observed when the frequency exceeded 3 times/day. This study demonstrates the importance of F-containing toothpaste in enamel re-/demineralization by varying the frequency of carbohydrate challenge in situ. [ABSTRACT FROM AUTHOR]

Dental erosion shows a typical distribution pattern within the dental arches. Tooth protection from erosion by salivary pellicle has been shown in vitro, but the hypothesis that pellicle may differ quantitatively at sites of erosion has not been investigated. This study aimed to determine the thickness of acquired salivary pellicle within the dental arches, investigate the possible relationship of this thickness to the distribution and severity of erosion within the arches, and confirm the protective effect of pellicle against dental erosion. Eight enamel blocks were produced from each of 5 bovine incisors assigned to five volunteers. Each block was further cut into 2 slabs, producing control and experimental slabs. Pellicle developed on experimental slabs located on 8 intra-oral sites after 1 hr of exposure was stained by "sheep anti-human IgGAM-FITC". Slabs were then visualized, and pellicle thickness measured, by confocal laser scanning microscopy. Eroded enamel lesions were produced in experimental and control slabs by means of pure orange juice. The degree of erosion was quantified by transverse microradiography. Pellicle thickness varied significantly within the dental arches and among individuals. An inverse relationship (r = -0.96, p < 0.001) was observed between the degree of erosion and pellicle thickness. Significant differences in erosion were observed between slabs with and those without pellicle. This study has shown that the thickness of acquired salivary pellicle varies within the dental arches, which may be responsible for the site-specificity of dental erosion, and that pellicle does protect the teeth from erosion. [ABSTRACT FROM AUTHOR]

Abstract Background Dental caries incidence in adults is similar to that in children and adolescents, but few caries preventive agents have been evaluated for effectiveness in adults populations. In addition, dentists direct fewer preventive services to their adult patients. Xylitol, an over-the-counter sweetener, has shown some potential as a caries preventive agent, but the evidence for its effectiveness is not yet conclusive and is based largely on studies in child populations. Methods/Design X-ACT is a three-year, multi-center, placebo controlled, double-blind, randomized clinical trial that tests the effects of daily use of xylitol lozenges versus placebo lozenges on the prevention of adult caries. The trial has randomized 691 participants (ages 21-80) to the two arms. The primary outcome is the increment of cavitated lesions. Discussion This trial should help resolve the overall issue of the effectiveness of xylitol in preventing caries by contributing evidence with a low risk of bias. Just as importantly, the trial will provide much-needed information about the effectiveness of a promising caries prevention agent in adults. An effective xylitol-based caries prevention intervention would represent an easily disseminated method to extend caries prevention to individuals not receiving caries preventive treatment in the dental office. Trial Registration ClinicalTrials.Gov NCT00393055

The primary aim of this study was to evaluate the clinical performance of nanofilled composite resin restorations in traumatized, endodontically treated maxillary incisors with structural loss of 40% or less. The performance of the restorations was assessed in terms of longevity (survival) and esthetics (success) over a 20-month period. The secondary objective was to employ a novel digital method to quantify preoperative tooth structure loss. Sixty-one fractured maxillary incisors in 55 patients were included in the study. The teeth were photographed with a digital single-lens reflex camera equipped with a macro ring flash. The amount of lost tooth structure was calculated with digital photography software. The teeth were restored with a nanohybrid composite resin and self-etching adhesive system bonding agent. To assess esthetics, color change in the blue-yellow axis (Δb*) of the composite resin restoration was evaluated digitally with the Commission Internationale de l'Eclairage (CIE) L*a*b color system. The Wilcoxon signed-rank test was used to assess Δb*, and a Kaplan-Meier survival analysis was used to assess the longevity of the restorations. The study findings showed a statistically significant difference between pretreatment and posttreatment b* values (P < 0.05), but the difference was too small to be clinically perceptible to the human eye. A total of 5 restorations (9.8%) failed. The remaining restorations survived for a mean (SD) period of 18.6 (4.4) months. The log-rank test did not show any significant association between the amount of residual tooth structure and success of the restoration. The results of this study showed that use of direct composite resin restorations in endodontically treated maxillary incisors resulted in acceptable survival and success rates. Trial registration: Clinical Trial Registry of India No. CTRI/2020/01/023019., Competing Interests: No conflicts of interest reported.