Description of a new laboratory evaluation method of interdental brush abrasion as a clinical hazard

OBJECTIVES

To simulate the abrasive potential of an interdental brush when applied with toothpastes and prophylactic gels/solutions in a novel laboratory brushing simulation set-up.

METHODS

A brushing device was customized to treat dentin samples mimicking a simplified interdental space with an interdental brush (ISO 2). The brushing, that is, 7200 strokes for 1 h, was performed with artificial saliva (control), a povidone-iodine solution, and slurries of chlorhexidine and fluoride gels as well as three toothpastes with different RDA values ranging from 29 to 100, respectively. The loss of dentin was profilometrically assessed and compared with ANOVA and Fishers LSD.

RESULTS

While artificial saliva as control, the solution and the gel slurries showed no measurable dentin loss, toothpastes resulted in a measurable linear surface damage with respect to the actual intrinsic RDA values and ranged from 12.6 to 26.5 μm (p < 0.001).

CONCLUSIONS

Any interdental cleaning product should be tailored and carefully instructed. Any over- and misuse should be avoided, which applies especially to the use of interdental brushes in combination with abrasive toothpastes.

Long-term evaluation (up to 7 years) of the use of a collagen matrix to treat gingival recession associated with noncarious cervical lesion: Report of two cases

INTRODUCTION

Gingival recession (GR) is a relevant clinical condition due to its high prevalence worldwide, which leads to aesthetic demands and dentin hypersensitivity. Collagen matrices have been associated with different designs of coronally advanced flaps (CAFs) to treat GR defects. However, the literature lacks long-term follow-up of this treatment option. The aim of this study is to present the long-term follow-up (up to 7 years) of two GR defects (associated or not with noncarious cervical lesion) treated with a CAF and a collagen matrix (CM).

CASE PRESENTATION

Case 1 underwent a CAF associated with a CM to treat a single GR defect. After 7 years, Case 1 presented with 3 mm of recession reduction, which corresponds with the 85.7% of root coverage. Case 2 presented two GR defects associated with noncarious cervical lesions (NCCLs). The NCCLs were partially restored with resin composite and then underwent a modified CAF for multiple defects and a CM. After 5 years of follow-up, Case 2 presented with 1.5 and 2.5 mm of recession reduction, which corresponds with the average 83.3% defect coverage.

CONCLUSION

These two cases may show that CMs can provide long-term stable outcomes in the treatment of GR defects. Why is this case new information? One of the cases is the first one to describe a 7 years of follow-up after CAF+CM to treat gingival recession defects. What are the keys to successful management of this case? Correct material handling. Adequate restorative protocol and surgical technique. What are the primary limitations to success in this case? Diagnose Patient compliance.

Multiple gingival recessions associated with non-carious cervical lesions treated by partial restoration and modified coronally advanced flap with either connective tissue graft or xenogeneic acellular dermal matrix: A randomized clinical trial

BACKGROUND

This study aimed to compare a connective tissue graft (CTG) to a (porcine) xenogeneic acellular dermal matrix (XDM), both associated with modified coronally advanced flap (MCAF) and partial resin composite restoration to treat multiple combined defects (CDs).

METHODS

Seventy-eight defects in 38 patients presenting multiple combined defects, that is, gingival recession associated with non-carious cervical lesions, were treated by partial resin composite restoration (apical margin up to 1 mm of the estimated cement-enamel junction) and MCAF along with CTG or XDM. After 6 months, the groups were compared with regard to clinical, patient-centered, and esthetic outcomes.

RESULTS

CD coverage was 72.9% for CTG versus 50.7% for XDM (P < 0.001). Recession reduction was 2.3 mm for CTG versus 1.5 mm for XDM (P < 0.001). CTG resulted in a greater increase in keratinized tissue width (CTG: 0.96 mm vs. XDM: 0.3 mm, P = 0.04) and gingival thickness (CTG: 0.9 mm vs. XDM: 0.3 mm, P < 0.001). Both treatments successfully reduced dentin hypersensitivity and increased esthetics satisfaction, with no statistically significant intergroup differences. Moreover, XDM patients experienced a shorter surgery duration (CTG: 57.2 min vs. XDM: 37.4 min, P < 0.001) and less time to no pain (visual analog scale  =  0; CTG: 6.5 days vs. XDM: 3.5 days, P = 0.04).

CONCLUSION

CTG resulted in significantly greater root coverage and increased keratinized tissue width compared to XDM for treating multiple partially restored CDs. However, increased root coverage at the CTG sites was accounted for by increased probing depth compared to the XDM sites.

Effect of different toothpastes on permeability and roughness of eroded dentin

Dentin hypersensitivity (DH) is characterized by rapid, acute pain arising from exposed dental tubules.

AIM

the aim of this study was to evaluate the roughness, tubule occlusion, and permeability of eroded dentin brushed with different toothpastes.

MATERIALS AND METHOD

ninety bovine teeth were cut into blocks. Thirty hemifaces were protected with varnish and the other sixty were submitted to permeability tests. Specimens were divided into groups according to the dentifrices: without fluoride (WF), sodium fluoride (NaF), and stannous fluoride (SnF2). The blocks were subjected to a 5-day erosive-abrasive protocol. Surface roughness and dentinal tubule occlusion (n=10) were assessed for both control and test hemifaces of the same sample along with permeability analysis (n=20). Two-way RM ANOVA and Tukey's post-hoc test were performed (p≤0.05).

RESULTS

NaF and SnF2 presented higher roughness than WF. The number of open tubules was higher in WF. Permeability was higher in SnF2, but there was no significant difference between WF and NaF.

CONCLUSIONS

both fluoride toothpastes occluded dentinal tubules and increased roughness. NaF toothpaste promoted greater decrease in dentin permeability.

Influence of masticating cycles and chewing patterns on inadvertent enamel wear caused by zirconia brackets

Little information is available about enamel wear caused by zirconia brackets, an inadvertent side effect of orthodontic treatment. The purpose of this study was to examine potential enamel damage induced by contact with zirconia brackets. Sliding and impact wear simulations were performed using bovine enamel specimens positioned at a 25° slant to a zirconium ball to determine wear behaviour. Different chewing patterns, tapping and grinding, were simulated. Specimens were profiled using confocal laser scanning microscopy, and the mean maximum depth and surface roughness were measured. Scanning electron microscopy was also performed. The mean maximum depth of wear values differed according to the number of mastication cycles, with a higher number of cycles producing higher depths of wear. The facet wear depth was significantly greater with the tapping pattern than with the grinding pattern. Scanning electron microscopic observation of the wear facets revealed that surface textures at the edges were rougher than those at the centre of all facets. The results of this study indicated that enamel wear was induced by contact with zirconia brackets during the early period of mastication, and that the patterns and number of cycles of mastication affected the wear progression of enamel.

Single gingival recession associated with non-carious cervical lesion treated by partial restoration and coronally advanced flap with or without xenogenous collagen matrix: A randomized clinical trial evaluating the coverage procedures and restorative protocol

BACKGROUND

Evaluate the use of collagen matrix (CM) as adjunctive to coronally advanced flap (CAF versus CAF + CM) to treat gingival recession (GR) associated with non-carious cervical lesion-combined defects (CDs).

METHODS

Sixty-two patients presenting 62 CDs (RT1 GR and non-carious cervical lesion (NCCLs) were randomly allocated to either CAF group (n = 31): partial restoration of the NCCL and CAF; or to CAF + CM group (n = 31): partial restoration of the NCCL and CAF associated with CM. Clinical, esthetic, patient-centered outcomes, and restorative parameters were assessed.

RESULTS

After 12 months, CD coverage were 55.2% for CAF and 54.4% for CAF + CM (P = 0.8). Recession reduction were 1.9 ± 0.8 mm for CAF and 2.0 ± 0.7 mm for CAF + CM (P = 0.6). CAF+CM resulted in higher increase in keratinized tissue (KT) width (CAF: 0.3 ± 0.7 mm; CAF + CM: 0.9 ± 0.8 mm; P = 0.004) and KT thickness gain (CAF: 0.1 ± 0.3 mm; CAF + CM: 0.7 ± 0.2 mm; P = 0.001). Both treatments presented low postoperative pain and resulted in esthetics improvements. In addition, no restoration was lost, 27.4% showed a reduction of the superficial polishing, and 8% showed marginal staining, but still clinically acceptable.

CONCLUSION

Partial resin composite restoration (with the apical limit up to 1 mm of the estimated CEJ) and CAF alone or combined with CM are suitable for treating CDs. The use of CM provided additional benefits in terms of KT width and thickness gain. (NCT03341598).

A profilometric and scanning electron microscopic analysis of tooth surface abrasion caused by rotary/oscillatory, linear motion, sonic, and ultrasonic toothbrushes: An in vitro study

Background:

Adequate plaque control facilitates good gingival and periodontal health, prevents tooth decay, and preserves oral health. Toothbrushing is the primary method of removing plaque and can be classified into powered and manual toothbrushes.

Aim:

The primary objective was to compare the abrasiveness and surface roughness caused by four different power-driven toothbrushes with a different mode of action, on tooth surfaces in vitro.

Materials and Methods:

An in vitro experiment was conducted on eighty freshly extracted tooth specimens which were equally divided into four groups. Each group was brushed with the specifically assigned electric toothbrush to that group, but keeping parameters such as force applied during brushing, storage of tooth before and after brushing, and toothbrushing time same. A total of the 2-month study was done on each tooth specimen. Tooth surface roughness was recorded before and after the toothbrushing experiment to check the difference between surface roughness readings. Scanning electron microscopic (SEM) analysis was done afterward to analyse the surface topography of each group specimens.

Statistical Analysis Used:

Paired t-test used for intergroup analysis and intragroup analysis was done using Kruskal–Wallis test.

Results:

After comparing the baseline and final readings of each group, it has been found that the mean difference between values is highly significant in Group 1 (rotary/oscillatory). The mean rank of Group 1 was least in all four groups, which showed the highest tooth surface abrasion in that group. SEM analysis also revealed that Group 1 tooth specimens had deeper scratches/lines comparatively to other groups.

Conclusion:

Rotary/oscillatory toothbrush caused the highest tooth surface abrasion when compared with other electronic toothbrushes.

New Volume-Stable Collagen Matrix and Modified Coronally Advanced Flap to Treat Multiple Gingival Recessions Associated with Partially Restored Non-Carious Cervical Lesions: A Case Report

INTRODUCTION

Gingival recession (GR) is a prevalent problem that is related to aesthetic demands and dentin hypersensitivity. Frequently, GR is associated with non-carious cervical lesion (NCCLs) forming a combined defect (CD), which requires restorative and surgical treatment. Connective tissue graft (CTG) procedures allow predictable root coverage but can result in patient discomfort and bleeding.

CASE PRESENTATION

This first case report describes multiple GRs associated with B+ NCCL at teeth #4 and 6 of a 27-year-old patient with a thin periodontal phenotype. The aim of this report was to evaluate the 6-month outcome of a new volume-stable collagen matrix (VCMX) combined with modified coronally advanced flap (MCAF) and partial restoration to treat CDs. After 6 months, significant improvement was observed regarding CD coverage (69.05%), recession reduction (RecRed) (2.25 mm), gingival thickness (GT) gain (0.74 mm) and keratinized tissue width (KTW) gain (0.75 mm). In addition, excellent aesthetic evaluation and patient comfort were achieved by using the biomaterial.

CONCLUSION

VCMX associated with MCAF and partial restoration may be an option to treat multiple recession defects plus B+ NCCLs. This article is protected by copyright. All rights reserved.

Comparative evaluation of cemental abrasion caused by soft and medium bristle hardness toothbrushes at three predetermined toothbrushing forces: An in vitro study

Background:

Plaque control has been shown to have a pivotal role in maintaining optimal periodontal health. Toothbrushing as a mechanical plaque control tool is the most popular and effective option for self-performed oral health maintenance. However, the detrimental effects of bristle hardness and force exerted by toothbrushes on the tooth surface are the areas of concern.

Objective:

The aim of this in vitro study was to evaluate the abrasive effect of two different manual toothbrushes exerting predetermined forces on cemental surfaces of the teeth.

Materials and Methods:

Sixty extracted first molars were selected. Totally six experimental groups were formed based on the three predetermined forces 1.5, 3, and 4.5 Newton (N) and two types of manual toothbrushes, i.e., soft and medium bristle hardness. Buccal and lingual surfaces were independently brushed for 5000 cycles using specially designed toothbrushing machine. Throughout the experiment, type and quantity of toothpaste were kept constant. Post 5000 cycles of toothbrushing, change in surface roughness was measured using profilometer in microns and change in weight indicating loss of substance was measured in milligrams.

Results:

Abrasion of cementum is force dependent. Data revealed that both soft and medium bristle hardness toothbrushes cause significant cemental abrasion at 3 and 4.5 N forces.

Conclusions:

Higher is the force, more is the cemental surface abrasion. Soft bristled toothbrush causes more cemental abrasion than medium bristled toothbrush at 3 and 4.5 N forces.

Dental Surface Texture Characterization Based on Erosive Tooth Wear Processes

The differential diagnosis of dental wear lesions affects their clinical management. We hypothesized that surface texture parameters can differentiate simulated erosion, abrasion, and erosion-abrasion lesions on human enamel and dentin. This in vitro study comprised 2 parts (both factorial 4 × 2), with 4 lesion types (erosion, abrasion, erosion-abrasion, and sound [no lesion; control]) and 2 substrates (enamel and dentin). Flattened/polished dental specimens were used in part 1, whereas natural dental surfaces were used in part 2. Testing surfaces were evaluated in blind conditions, using average surface roughness (Sa) and the following scale-sensitive fractal analysis parameters: area-scale fractal complexity (Asfc), exact proportion length-scale anisotropy of relief (eplsar), scale of maximum complexity (Smc), and textural fill volume (Tfv). Two-way analyses of variance, followed by Fisher's protected least significant difference tests (α = 0.05), were used to evaluate the effects of lesion and substrate. Classification trees were constructed to verify the strength of potential associations of the tested parameters. In part 1,Asfc, Sa, and Tfv were able to differentiate erosion and erosion-abrasion lesions from the sound (no lesion) control in both substrates; only Asfc differentiated erosion and erosion-abrasion enamel lesions (allP< 0.05). The best association of parameters correctly classified up to 84% and 94% of the lesions on enamel and dentin, respectively. In part 2, only Asfc differentiated erosion and erosion-abrasion lesions from the sound (no lesion) control in both substrates, whereas eplsar was able to differentiate erosion from erosion-abrasion (allP< 0.05). The association of parameters correctly classified up to 81% and 91% of the lesions in enamel and dentin, respectively.Asfc, Sa, and Tfv were able to differentiate erosion and erosion-abrasion lesions, despite their complicated surface textures. The association of parameters improved the differentiation of lesions for both enamel and dentin in polished or natural surfaces.

Microhardness evaluation of silorane and methacrylate composites submitted to erosion and abrasion processes

Objective: The aim of this study was to evaluate the Knoop hardness number (KHN) of methacrylate (MC) and silorane (SC) composites after being submitted to erosion and abrasion processes. Material and methods: Forty samples were made with each composite: MC and SC. The samples were divided into eight groups (n = 10) according to the type of composite (G1-G4, MC; G5-G8, SC) and the beverages involved in the erosion process (G1 and G5 - Control (C), without erosion, with abrasion; G2 and G6 - Orange Juice (OJ), abrasion; G3 and G7 - Smirnoff Ice® (SI), abrasion; G4 and G8 - Gatorade® (GA), abrasion). The KHN test was performed 24 h after the last cycle of erosion/abrasion. Results: The MC groups showed smaller KHN values for the SI group (p < 0.05) when compared to the Control and OJ groups; however, for the SC groups, no differences were found (p > 0.05). Conclusion: Methacrylate composite when submitted to acidic beverages erosive challenge combined with abrasive process might alter its surface microhardness. However, the beverages used in the present study were not able to interfere in silorane composite surface microhardness.

Surface Roughness of Composite Resins after Simulated Toothbrushing with Different Dentifrices

BACKGROUND

The aim of the study was to evaluate, in vitro, the surface roughness of two composite resins submitted to simulated toothbrushing with three different dentifrices.

MATERIALS AND METHODS

Totally, 36 samples of Z350XT and 36 samples of Empress Direct were built and randomly divided into three groups (n = 12) according to the dentifrice used (Oral-B Pro-Health Whitening [OBW], Colgate Sensitive Pro-Relief [CS], Colgate Total Clean Mint 12 [CT12]). The samples were submitted to 5,000, 10,000 or 20,000 cycles of simulated toothbrushing. After each simulated period, the surface roughness of the samples was measured using a roughness tester.

RESULTS

According to three-way analysis of variance, dentifrice (P = 0.044) and brushing time (P = 0.000) were significant. The composite resin was not significant (P = 0.381) and the interaction among the factors was not significant (P > 0.05). The mean values of the surface roughness (µm) followed by the same letter represent no statistical difference by Tukey's post-hoc test (P <0.05): Dentifrice: CT12 = 0.269(a); CS Pro- Relief = 0.300(ab); OBW = 0.390(b). Brushing time: Baseline = 0,046ª; 5,000 cycles = 0.297(b); 10,000 cycles = 0.354(b); 20,000 cycles = 0.584(c).

CONCLUSION

Z350 XT and Empress Direct presented similar surface roughness after all cycles of simulated toothbrushing. The higher the brushing time, the higher the surface roughness of composite resins. The dentifrice OBW caused a higher surface roughness in both composite resins.

Effect of Toothpastes with Different Abrasives on Eroded Human Enamel: An in situ/ex vivo Study

The aim of the present study was to investigate the abrasive effect of CaCO₃ and SiO₂-based fluoride-free experimental toothpastes on eroded human permanent dental enamel and evaluate the effectiveness of waiting periods between acid exposure and tooth brushing. Twelve volunteers wore palatal appliances containing human enamel blocks for two periods of five days each. The appliances were immersed in a soft drink for five minutes four times a day (9:00 am, 11:00 am, 2:00 pm and 4:00 pm). On two occasions, two blocks were not submitted to additional treatment; two blocks were brushed (30 s) either with a CaCO₃ or SiO₂ toothpaste immediately after erosion and two blocks were brushed 1 h after erosion. Thus, the sample was divided into six groups: erosion alone (CaCO₃ and SiO₂ control); brushing with fluoride-free toothpaste (CaCO₃ immediate and 1 h after erosion; SiO₂ immediate and 1 h after erosion). Significant differences in wear depth were found between the enamel blocks in the CaCO₃ immediate and 1 h after erosion groups and the blocks in the CaCO₃ control group (p=0.001; p=0.022). No significant differences were found regarding the change in roughness and wear depth between blocks submitted to immediate abrasion and 1 h after erosion (CaCO₃ and SiO₂). The data revealed that surface roughness and wear depth is increased when erosion is combined with dental abrasion, regardless of the abrasive used. Waiting for 1 h to brush the eroded blocks offered no protective effect.