Quantification of Bacterial Colonization in Dental Hard Tissues Using Optimized Molecular Biological Methods

Bacterial infections of root canals and the surrounding dental hard tissue are still a challenge due to biofilm formation as well as the complex root canal anatomy. However, current methods for analyzing biofilm formation, bacterial colonization of root canals and dental hard tissue [e.g., scanning electron microscopy, confocal laser scanning microscopy (CLSM) or determination of colony forming units (CFU)] are time-consuming and only offer a selective qualitative or semi-quantitative analysis. The aim of the present study is the establishment of optimized molecular biological methods for DNA-isolation and quantification of bacterial colonization via quantitative PCR (qPCR) from dental hard tissue. Root canals of human premolars were colonized with Enterococcus faecalis. For isolation of DNA, teeth were then grinded with a cryo mill. Since the hard tissues dentin and especially enamel belong to the hardest materials in the human organism, the isolation of bacterial DNA from root dentin is very challenging. Therefore, treatment steps for the isolation of DNA from grinded teeth were systematically analyzed to allow improved recovery of bacterial DNA from dental hard tissues. Starting with the disintegration of the peptidoglycan-layer of bacterial cells, different lysozyme solutions were tested for efficacy. Furthermore, incubation times and concentrations of chelating agents such as EDTA were optimized. These solutions are crucial for the disintegration of teeth and hence improve the accessibility of bacterial DNA. The final step was the determination of prior bacterial colonization of each root canal as determined by qPCR and comparing the results to alternative methods such as CFU. As a result of this study, optimized procedures for bacterial DNA-isolation from teeth were established, which result in an increased recovery rate of bacterial DNA. This method allows a non-selective and straightforward procedure to quantify bacterial colonization from dental hard tissue. It can be easily adapted for other study types such as microbiome studies and for comparable tissues like bones.

PREVALENCE OF DISEASE IN THE CONSERVATIVE DENTISTRY DEPARTMENT OF GUSTI HASAN AMAN DENTAL HOSPITAL BANJARMASIN IN 2015-2018 (RETROSPECTIVE STUDY)

ABSTRACTBackground: The most common disease in society is dental problems. People often care less about oral health. Dental hard tissue disease is considered as a mild disease, not contagious and not life-threatening, so people will visit the dentist if they feel disturbed, especially in terms of mastication, swallowing and speaking. Dental hard tissue diseases in conservative dentistry that often causes problems are reversible pulpitis, irreversible pulpitis, and pulp necrosis. Until now, there are no definitive data on the prevalence of dental hard tissue disease in conservative dentistry in Indonesia, as well as data on the prevalence of dental hard tissue disease in Banjarmasin, South Kalimantan. Purpose: To find out the prevalence of hard tissue disease in conservative dentistry in patients who came to Gusti Hasan Aman Dental Hospital, Banjarmasin, South Kalimantan in 2015-2018. Methods: This research was a descriptive study through a retrospective study. Samples in this study were taken by purposive sampling method, totaling 11,480 medical records of patients who came to the Conservative Dentistry Department at Gusti Hasan Aman Dental Hospital Banjarmasin in 2015-2018. Results: The data obtained showed the prevalence of reversible pulpitis as many as 6,700 (59%), irreversible pulpitis as many as 1,291 (11%), pulp necrosis of 3,234 people (28%), and others as many as 255 people (2%). Conclusion: The highest prevalence of dental hard tissue disease in the Conservative Dentistry Department of Gusti Hasan Aman Dental Hospital in 2015-2018 is reversible pulpitis, followed by pulp necrosis, and irreversible pulpitis. Keywords: Necrosis, Prevalence, Pulpitis,

4-Hexylresorcinol Administration Increases Dental Hard Tissue Formation and Incisor Eruption Rate in Rats

Dental hard tissue formation and bone turnover are required for tooth eruption. 4-Hexylresorcinol (4HR) accelerates tooth movement by increasing bone turnover in orthodontic treatment. This study aimed to evaluate the following: (1) the effect of 4HR application on the expression of proteins associated with tooth formation, and (2) the effect of 4HR application on mandibular incisor eruption rate in a rat model. Primary cultured pulp cells received either 4HR (1 to 100 µM) or solvent only; western blotting was performed for transforming growth factor-beta 1 (TGF-β1), bone morphogenic protein-2/4 (BMP-2/4), runt-related transcription factor 2 (Runx2), osterix (OSX), dentin sialophosphoprotein (DSPP), and parathyroid hormone-related protein receptor (PTHrP-R). In in vivo study, rats (15 males and 15 females) received either solvent or 0.128 mg/kg or 12.8 mg/kg of 4HR via subcutaneous injection; mandibular incisor eruption rate was subsequently recorded. Immunohistochemical staining and western blotting for TGF-β1, BMP-2/4, Runx2, OSX, DSPP, and PTHrP-R were performed in the mandibular tissue samples. 4HR administration was found to increase TGF-β1, BMP-2/4, Runx2, OSX, DSPP, and PTHrP-R expression in both cell culture and tissue samples. Immunohistochemical staining of some markers showed site-specific expression, thereby indicating programmed differentiation of odontoblasts and ameloblasts. The eruption rate was significantly higher in the 12.8 mg/kg 4HR-administered group than in the untreated control (p = 0.001 and 0.010 for males and females, respectively). Collectively, 4HR administration increased the expression of markers related to dental hard tissue formation and accelerated the eruption rate of incisors in rats.

AN ELECTRONIC EXCEL-CALCULATOR FOR CALCULATING DENTAL CROWN VOLUMES

Previous studies have found that with increasing volume of hard tissues defect, the sensitivity of the restored structure to the physical and mechanical restoration characteristics is increasing too. Since existing volume determination techniques cannot be use in a clinical setting, this gives reason to consider the problem of volume determination dental hard tissue defects extremely important, and this research-relevant. Aims of research. Develop and evaluate the possibility of using methods to determine dental crown volumes and volumes of defects in hard tooth tissue. Materials and methods of research. For determination of crown volumes and defect volumes of hard tooth tissues for each group of teeth were used appropriate geometric models. Together with the built models, were performed the mathematical calculations to calculate their linear dimensions. Results of the research. We have developed and substantiated the feasibility of using an electronic Excel calculator to calculate dental crown volumes in clinical settings. Conclusions. Using our electronic Excel calculator to calculate tooth crown volumes and methods for determining the volume of dental hard tissue defects, in clinical settings we can objectify the diagnostic process in the presence of dental hard tissue defects.

Optical Polarimetric Detection for Dental Hard Tissue Diseases Characterization

Dental enamel constitutes the outer layer of a crown of teeth and grows nearly parallel. This unique nanostructure makes enamel possess birefringence properties. Currently, there is still no appropriate clinical solution to examine dental hard tissue diseases. Therefore, we developed an optical polarization imaging system for diagnosing dental calculus, caries, and cracked tooth syndrome. By obtaining Stokes signals reflected from samples, Mueller images were constructed and analyzed using Lu-Chipman decomposition. The results showed that diattenuation and linear retardance images can distinguish abnormal tissues. Our result also aligns with previous studies assessed by other methods. Polarimetric imaging is promising for real-time diagnosing.

In Vitro Assessment of Erosive Effects of Some Common Soft Drinks on Dental Hard Tissues

Summary Background/Aim: The chemical nature of soft drinks is acidic, so they possess the capacity to cause hard tissue erosion. The aim of this study is to assess the potentially erosive effect linked to pH and titratable acidity of some common soft drinks on dental hard tissues in prolonged time exposure. Material and Methods: Seven types of soft drinks in Romanian market were selected for this study. The pH and Titratable acidity were determined. Twenty one human dental hard tissue specimens were immersed in 5 ml solution each for 336h. Every 48h weight loss was determined for each specimen and after 336h volume changes were calculated. Enamel microhardness was determined using a Microhardness Tester model HV-1000 and compared to normal enamel microhardness. Results: The pH values of beverages ranged from 2.37 to 3.1, showing no significant differences. All specimens presented color and surface texture modifications, weight loss and volume reduction. There were found significant differences between the mean values of weight loss and enamel microhardness of each type of specimens and type of beverages tested. The most representative findings were achieved by indentations done in specific zones on Sprite® immersed specimen. This result suggest that microhardness near the eroded surface was significant lower than in other zones. Conclusions: Data obtained have shown that all the soft drinks tested had an erosive effect, causing dental hard tissue dissolution. For prolonged time exposure titratable acidity may be a major predictor for erosive potential. Dental erosion may affect different levels of enamel causing decreased enamel microhardness.

Perbedaan Kekuatan Geser Perlekatan (Shear Bond Strength) Antara Self – Adhering Flowable Composite dan Flowable Composite dengan Sistem Adhesif Self – Etch pada Dentin

Restoration is a treatment to restore the structure of missing dental hard tissue due to caries. Flowable composite has good adaptability to the cavity wall so that it is widely used as an intermediate layer. Composite resins require an adhesive system to bond chemically with dental hard tissue. Self - adhering flowable composite combining etching, priming, and adhesive in one flowable package. This study was conducted with the aim to determine the difference in shear bond strength between Self – adhering flowable composite and flowable composite with self – etch adhesive system on dentine. The number of samples used was 38 pieces. After dentin was prepared and fixed, samples was divided into 2 groups, each group consisting of 19 samples. First group was applied with self – adhering flowable composite, second group was applied with flowable composite with self – etch adhesive system. Samples was immersed in pH 6.8 normal saline and stored for 24 hours, then dried and shear bond strength was tested using a universal testing machine. The data obtained were analyzed using independent t – test. The statistical analysis using independent t – test showed that there were significant differences in the shear bond strength between the two groups, p=0,000 (p<0.05). The study concluded that there is difference of shear bond strength between self – adhering flowable composite and flowable composite with self – etch adhesive system on dentine.