Effect of different scaling methods and materials on the enamel surface topography: An in vitro SEM study

Effect of Two Different Intraoral Polishing Systems on Surface Roughness, Color Stability, and Bacterial Accumulation of Zirconia-Reinforced Lithium Silicate Ceramic

OBJECTIVE

 The aim of this study was to investigate the effects of two intraoral polishing methods on zirconia-reinforced lithium silicate ceramic after ultrasonic scaling.

MATERIALS AND METHODS

 Thirty disc-shaped samples of zirconia-reinforced lithium silicate were constructed. Freshly extracted bovine teeth were collected and cleaned then the discs were cemented into a cavity prepared onto their labial surface. The samples were divided into three groups (10 samples per group); S: Scaling only, SE: Scaling followed by polishing using Eve Diapro lithium disilicate polishers, SD: Scaling followed by polishing using Diatech ShapeGuard ceramic polishing plus kit. The surface roughness was evaluated after scaling and polishing the samples. For color stability, the samples were stored for 12 days at 37°C in an incubator to simulate 1-year consumption of coffee. L*a*b* color parameters were assessed using VITA Easyshade Advance 4.0 before and after the staining procedure and the color difference was measured. Finally, bacterial accumulation was evaluated by incubating the samples with a suspension of Streptococcus mutans ( S. mutans), after that the S. mutans colonies were counted to obtain the values of colony-forming units (CFU). The final overall roughness, change in color and bacterial count were compared between all groups using one-way ANOVA and Tukey's post-hoc analysis. The Pearson correlation coefficient was used to determine the correlation between continuous variables. The cutoff for significance was chosen at p ≤ 0.05.

RESULTS

 Scaling induced surface roughness of the zirconia-reinforced lithium silicate ceramic was significantly decreased after using both intraoral polishing systems and this was accompanied by a significant decrease in color change and bacterial count.

CONCLUSION

 Intraoral polishing techniques can reduce the roughness of the surface of zirconia reinforced lithium silicate restorations induced due to scaling and subsequently reduce the stainability and bacterial accumulation.

Evaluating the Effects of Cigarette Smoking and Heated Tobacco Products on Hard Dental Tissues: A Comparative Histological and Colorimetric Analysis

OBJECTIVES

This study aimed to evaluate and compare the impact of cigarette smoking (CS) and heated tobacco (HT) on the alteration of color and ultrastructural characteristics of human enamel and cementum.

BACKGROUND

According to tobacco companies, a less harmful substitute for CS is HT products. Nevertheless, comprehensive research on the effects of HT on tooth structures has been lacking. This study aimed to evaluate and compare the impact of CS and HT on the alteration of color and ultrastructural characteristics of human enamel and cementum.

MATERIALS AND METHODS

Thirty intact and noncarious human maxillary premolars extracted for orthodontic treatment purposes, previously disinfected, were used in the study. The specimens were randomly separated into six groups (n = 10), as follows: Group 1: enamel without smoking exposure; Group 2: enamel exposed to CS; Group 3: enamel exposed to HT; Group 4: cementum without smoking exposure; Group 5: cementum exposed to CS; and Group 6: cementum exposed to HT. The measurement of color change was conducted using a spectrophotometer. The surface alterations and mineral composition of enamel and cementum were evaluated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. ANOVA test followed by Tukey's post hoc test was used to determine significant differences between groups.

RESULTS

Results showed that CS had a more pronounced effect on enamel and cementum color changes than HT. The impact of CS and HT on color changes was more evident in cementum than in enamel. Surface morphology of enamel and cementum showed alterations in histology following exposure to both smoking types. Moreover, the mineral content experienced a significant reduction after using CS and HT. The reduction in calcium content after CS and HT exposure was similar. However, HT led to a significant decrease in the phosphorus content of enamel when compared with CS. At the same time, CS exposure in cementum resulted in a more significant reduction in Ca/P ratio than HT.

CONCLUSIONS

Although HT may appear to present a lower danger to hard dental tissues than CS, it is not entirely harmless. CS results in more color changes on the enamel and cementum of teeth. Both smoking methods affected the mineral content of teeth, with CS having a significant effect on the roots, while HT significantly affected the crowns' mineral composition.

Effect of Hand and Ultrasonic Scaling-Root Planing Methods on Tooth Surface Topography: An In-Vitro Atomic Force Microscopy Study

PURPOSE

Any instrumentation on the tooth surface for plaque or calculus removal will cause some amount of roughness on the tooth surface. Hence, this study was proposed to investigate the effects of hand and ultrasonic scaling and root planing on enamel and cementum, respectively.

MATERIALS AND METHODS

Forty tooth samples were prepared from extracted maxillary and mandibular first pre-molars and were divided randomly into four groups of 10 samples each. Group l: received ultrasonic scaling on enamel; Group II: received hand scaling on enamel surface; Group III: root planing with an ultrasonic unit on the cementum samples; and Group IV: root planing using hand curettes on cementum surface. The amount of roughness produced on the surface of each sample of all four groups was evaluated using atomic force microscopy (AFM) and statistically analyzed using Chi-square, ANOVA, and Wilcoxon tests.

RESULTS

The results suggested that the surface roughness produced on both crown and root after scaling and root planing (SRP) using a hand instrument is lower than that of an ultrasonic unit. The roughness of the crown was found to be lower than that of the root after SRP using both a hand instrument and an ultrasonic unit and was also statistically significant (P = 0.034). In contrast, there is not enough evidence to conclude a significant difference (P=0.13) between root planing using hand instruments and ultrasonic scaler groups. The combined p-value using the Chi-square test (P=0.026) suggests a statistically significant overall difference between crown and root groups.

CONCLUSION

From the present study, the authors concluded that scaling as well as root planing using an ultrasonic unit cause more tooth (enamel and cementum) surface roughness as compared to hand scaling and root planing. While there is no significant difference in the surface roughness of root-cementum produced due to the root planing in both groups, crown-enamel exhibits a significant difference after scaling in both groups. Clinical significance of the study: Rough, uneven tooth surfaces negatively influence the anticipated healing of the periodontium by providing retention areas for microbial dental plaque.

Aesthetic management of discoloured incisors in children

Children can often present with discolouration of their teeth, commonly affecting their permanent maxillary central incisors. These opacities can often cause children to suffer with psychosocial and confidence related issues. With long waiting lists in secondary care, many children may face increased waiting times to receive aesthetic dental treatment. It is important that the dental professional is aware of the different causes of discolouration, the possible treatment options and when to consider a referral to secondary care.

Effect of Different Scaling Methods on the Surface Topography of Different CAD/CAM Ceramic Compositions

This study evaluated the effect of ultrasonic and manual scaling using different scaler materials on the surface topography of computer-aided designing and computer-aided manufacturing (CAD/CAM) ceramic compositions. After scaling with manual and ultrasonic scalers, the surface properties of four classes of CAD/CAM ceramic discs: lithium disilicate (IPE), leucite-reinforced (IPS), advanced lithium disilicate (CT), and zirconia-reinforced lithium silicate (CD) of 1.5 mm thickness were evaluated. Surface roughness was measured before and after treatment, and scanning electron microscopy was used to evaluate the surface topography following the performed scaling procedures. Two-way ANOVA was conducted to assess the association of the ceramic material and scaling method with the surface roughness. There was a significant difference in the surface roughness between the ceramic materials subjected to different scaling methods (p < 0.001). Post-hoc analyses revealed significant differences between all groups except for IPE and IPS where no significant differences were detected between them. CD showed the highest surface roughness values, while CT showed the lowest surface roughness values for the control specimens and after exposure to different scaling methods. Moreover, the specimens subjected to ultrasonic scaling displayed the highest roughness values, while the least surface roughness was noted with the plastic scaling method.