Objective To study the effect of using different cement types under pediatric stainless-steel crown (SSC) around mandibular second primary molar using three-dimensional (3D) finite element analysis. Materials and Methods A 3D finite element model was built for pediatric mandibular molar by laser scanning of natural extracted tooth. Four types of cement (zinc phosphate, glass ionomer, resin-modified glass ionomer, and resin) of 200 μm layers thickness were tested under a stainless-steel crown of 130-μm thickness. Twelve case studies were reported within this research, as the applied load of 330 N was tested with three angulations: vertical, oblique at 45°, and laterally. Results Linear static stress analysis was performed. The resultant stresses and deformations' distribution patterns did not change with cement type, while the values were altered. All deformations and stresses were found within the normal range. Conclusions Analysis results indicated that using stiffer cement material increases tooth structure stresses and reduces crown body stresses and deformations, while bone was nearly insensitive to cement type.

IntroductionThe empathetic behaviour of dentists is essential for perfect patient care. Because the behaviour of child patients in a dental clinic differs from that exhibited by the adults, knowing of empathy of dental students towards the child in the dental clinic is an important concern.MethodsWe distributed a modified form of the Health Professions Student version (HPS‐version) of the Jefferson Scale of Empathy (JSE) to dental students in two rounds: (R1) before and (R2) after introducing behaviour guidance subcourse and exposure to 3 clinical experiences with children to measure changes in empathy of dental students towards child patients. The modifications include replacing the “patient” words with “child patients” and translation into Arabic. We checked the internal consistency of the modified form of HPS‐version by Cronbach's coefficient alpha test. The significance level was set at 0.05 for all statistical analyses.ResultsOut of eighty‐one, sixty‐five dental students completed the survey and attended a behaviour guidance course and three clinical sessions. The questionnaire showed accepted reliability. There was a significant decrease in the empathy of dental students in R2 than R1 (P < .05). The level of empathy for males was less than female students in both rounds (P < .05).ConclusionsThe clinical interaction of children by dental students inhibits their empathy towards child patients, and a specific training course is needed to improve dental students’ empathy towards children since learning behaviour guidance may not sufficient.

To evaluate a fixed-space maintainer made of light-cure acrylic resin (LCAR) for its flexural and shear bond strength using different bonding systems to the enamel. 45 extracted primary teeth were selected. They were randomly divided into three equal groups (n = 15) along with the type of adhesive system (Tetric Flow, Transbond XT, and Fuji Ortho LC) used for bonding (LCAR) to the tooth surface. Surfaces were treated; LCAR was attached to the treated surfaces using a split Teflon mold. For flexural strength testing, ten bars of LCAR were made using another Teflon-split mold. Shear bond strength and mean flexural strength values were evaluated by a universal testing machine. The highest values of bond strength were recorded for Transbond XT, followed by Tetric Flow, while the lowest values were for Fuji Ortho LC. Various groups had a significant difference as investigated by ANOVA. ARI scores showed no significant difference in debond sites. Mean value and standard deviation of flexural strength for LCAR were 82.83  ± 5.2. LCAR has superior mechanical properties and could be an alternative to currently-in-use space maintainer though in vivo and in vitro trials are needed to progress the ultimate design of LCAR.

AIM: The aim of the current in vitro study was to evaluate the changes in surface roughness of bulk fill composites after simulated toothbrushing with different dentifrices. MATERIALS AND METHODS: Three types of bulk fill resin composites were used in this study; 27 specimens of each composite resin were randomly divided into three main groups (n = 9). Each main group was further subdivided into three subgroups (n = 3). Each group was subjected to simulated toothbrushing with three different dentifrices. One-way analysis of variance was used to evaluate the effect of brushing using dentifrices on the surface roughness of each type of composite resin, followed by Tukey’s test at a significance level of p ≤ 0.5%. RESULTS: Results revealed that different effects on composite surface roughness were detected after simulating toothbrushing with different dentifrices. Lacalut toothpaste abrades more with Filtek Bulk Fill, Tetric N-Ceram then Bulk Fill SDR. Crest 3D toothpaste abrades more with Tetric N-Ceram, Bulk Fill SDR then Filtek Bulk Fill. BlanX toothpaste abrades more with Tetric N-Ceram, Bulk Fill SDR then Filtek Bulk Fill. CONCLUSION: Chemical composition of both resin composites and dentifrices plays an important role in influencing the degree of surface roughness of bulk fill composite resin restorations.

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Objective To study the possibility of using pediatric endocrowns to restore the second primary molar using three-dimensional (3D) finite element analysis. Design A 3D finite element model was built for a pediatric mandibular molar, starting with laser scanning a naturally extracted tooth. The access cavity had an elliptic shape with 6 mm width, 4 mm height, and 2 mm depth with a wall taper angle of 5 degrees.Two materials (Zr and E-max) were tested for the endocrown and two cementing materials (glass ionomer and resin cement) with 20 to 40 μm thickness. Twelve case studies were reported within this research as the applied load of 330 N was tested with three angulations vertical, oblique at 45 degrees, and laterally. Results Twelve linear static stress analyses were performed. The resultant stresses and deformations' distribution patterns did not alter much, and values were within the threshold of physiological tolerance. Deformations were negligibly changed with changing endocrown and cement materials. In contrast, endocrown stresses indicated zirconia endocrown would have a long lifetime, while E-max one will have a relatively short lifetime. Conclusions Analysis results indicated that bone was negligibly affected by changing endocrowns and cementing materials. Both tested endocrown materials can be used safely. Zirconia endocrowns may have a much longer lifetime than E-max.

Background: glass ionomer is one of the most frequently used restorative materials for primary teeth restoration. It has been in use for more than 30 years. Their restoration usefulness is preferential compared to other restorations due to their fluoride release and recharge, chemical adhesion to the structure of the dentin and their range of uses. Increasing the antibacterial efficacy of restorative materials is one of the primary goals to decrease the incidence of recurrent caries. Chlorhexidine is the gold standard antibacterial agent in dentistry. Objectives: the objective of this study is to evaluate the antibacterial effect of Chlorhexidine incorporated with glass ionomer on streptococcus mutans. Methods: Thirty Children between ages ranged 6-9 years old were selected to participate in this study. Children with bilateral caries in lower second primary molars affecting the occlusal and proximal surfaces without pulpitis were included in the study. All cavities were divided into two groups; group (A) restored with Glass Ionomer and group (B) restored with Glass Ionomer Chlorhexidine mixture. The sound proximal surfaces in all cavitated teeth acted as a control. After one month, two months and three months’ plaque samples were obtained and streptococcus mutans counts were calculated. Results: The number of SM taken from sound proximal surfaces for all groups were not changed significantly in whole periods of study. At the all-time interval, the mean log10 of SM in CHX group was lower than GI group and the difference was statistically significant. There is a significant difference in the mean log10 of SM in CHX group between the 1St month and the 3rd month. Conclusion: The growth of SM was found to be higher in the sound tooth than in GI groups and in GI group was higher than in CHX- GI mixture up to three months.