Journal of Dental Research, Dental Clinics, Dental Prospects
Volume:11 Issue: 1, Winter 2017

In vitro studies have revealed a direct association between resin content and cytotoxicity of resin composites; but implantation studies in this regard are sparse. This study investigates the relationship between filler content of composite resins and biocompatibility.
This study was conducted using 18 male Wistar rats (180-200g), 1 nano-hybrid (Prime-Dent Inc.) and 1 micro-hybrid (Medental Inc.) composites containing 74% and 80-90% filler content respectively. The samples were assessed on the 2nd, 14th and 90th day of implantation. Four rats were allocated to each day in the experimental group, while two were allocated to the control group. A section of 1.5mm long cured nano-hybrid and micro-hybrid materials were implanted into the right and left upper and lower limbs of the rats respectively. Eight samples were generated on each day of observation. Inflammation was graded according to the criteria suggested by Orstavik & Major. The average scores were calculated.
The average grade of inflammation for the nano-hybrid on the 2nd day of implantation was 3.3. The micro-hybrid resin had a score of 3.0 for inflammation. On the 14th day, the micro-hybrid resin also had a lower average grade for cellular inflammation. On the 90th day, the micro-hybrid resin had a higher grade of inflammation (0.9) as against 0.3 recorded for nano-hybrid.
The resin composites with higher filler content elicited lower grade of inflammation in the first two weeks of implantation, but after three months the converse was the case.

Background. The color masking ability of a restoration plays a significant role in coveringa discolored substructure; how-ever, this optical property of zirconia ceramics has not been clearly determined yet. The aim of this in vitro study was to evaluate the color masking ability of a zirconia ceramic on substrates with different values.
Methods. Ten zirconia disk specimens,0.5 mm in thickness and 10 mm in diameter, were fabricated by a CAD/CAM sys-tem. Four substrates with different values were prepared, including: white (control), light grey, dark grey, and black. The disk specimens were placed over the substratesfor spectrophotometric measurements. A spectrophotometer measured the L*, a*, and b* color attributes of the specimens. Additionally, ΔE values were calculated to determine the color differences betweeneach group and the control,and were then compared with the perceptional threshold of ΔE=2.6. Repeated-measures ANOVA, Bonferroni, and one-sample t-testwere used to analyze data. All the tests were carried out at 0.05 level of significance.
Results. The means and standard deviations of ΔE values for the three groups of light grey, dark greyand black were 9.94±2.11, 10.40±2.09, and 13.34±1.77 units, respectively.Significant differences were detected between the groups in the ΔE values (P2.6) (P Conclusion. Within the limitations of this study, it was concluded that the tested zirconia ceramic did not exhibit sufficient colormasking ability to hide thegrey and black substrates.

Background. Many types of toothpastes contain substances that can remineralize initial enamel caries. This study aimed to assess the effect of nano-hydroxyapatite (NHA) on microhardness of artificially created carious lesions.
Methods. In this in vitro study, NHA was prepared using sol-gel technique and added to the toothpaste with 7% concentration. A total of 80 extracted sound teeth were collected. The crowns were polished using 500-grit abrasive paper. The specimens were randomly coded from 1 to 80. Number 1 to 40 were assigned to group A and numbers 41 to 80 to group B. The microhardness was measured using HVS-1000 Vickers microhardness tester. The specimens were demineralized using 37% phosphoric acid for 3 minutes in order to create artificial carious lesions and then were rinsed with water, air-sprayed for 3 minutes and dried. Microhardness was measured again. Next, the specimens were brushed for 15 days, twice daily, for 15 seconds. After 15 days, microhardness was measured again. Toothpaste A contained NHA and fluoride and toothpaste B contained fluoride alone. Data were analyzed using SPSS 16, with one-sample Kolmogorov-Smirnov test and ANOVA at a significance level of P Results. The microhardness of specimens significantly decreased following acid exposure (P Conclusion. The toothpaste containing NHA was more effective than the toothpaste without NHA for the purpose of remineralization.

Statins are the recently evolved agents that aid in periodontal regeneration and ultimately attaining periodontal health. Atorvastatin (ATV) and Simvastatin (SMV) are specific competitive inhibitors of 3-hydroxy-2-methyl-glutaryl coenzyme A reductase. The present study was designed to evaluate and compare the effectiveness of 1.2% ATV, and 1.2% SMV as an adjunct to scaling and root planing (SRP) in the treatment of intrabony defects in subjects with chronic periodontitis.
Ninety six subjects were categorized into three treatment groups: SRP plus 1.2% ATV, SRP plus 1.2% SMV and SRP plus placebo. Clinical parameters; full mouth plaque index (PI), modified sulcus bleeding index (mSBI), probing depth (PD), and relative attachment level (RAL) were recorded at baseline before SRP and at 3, 6 and 9 months. Percentage radiographic defect depth reduction was evaluated using computer-aided software at baseline, 6 months and 9 months.
Both ATV and SMV showed significant PD reduction and RAL gain than placebo. Mean PD reduction and mean RAL gain was found to be greater in ATV group as compared to SMV, at 3, 6 and 9 months. Furthermore, ATV group sites presented with a significantly greater percentage radiographic defect depth reduction (33.23±3.11%; 34.84±3.07%) as compared to SMV (30.39±3.36%; 32.15±3.37%) at 6 and 9 months.
ATV showed greater improvements in clinical parameters with greater percentage radiographic defect depth reduction as compared to SMV in treatment of intrabony defects in CP subjects.

Background. The present study was conducted to investigate the marginal bone loss around two different types of im-plant‒abutment junctions, called platform-switched (Implantium system) and non-platform switched (XiVE system) after two years of loading.
Methods. Sixty-four implants in 49 patients were included in the study. The implants were placed in the posterior mandi-bular region according to the relevant protocols. The extent of bone loss around the implants was measured and compared after 24 months, using digital parallel periapical radiographs.
Results. The means ± SE of bone loss values in the platform-switched and non-platform-switched groups were 0.47 ± 0.048 mm and 1.87 ± 0.124 mm, respectively. The difference between the two groups was statistically significant (P Conclusion. The platform-switching technique seems to reduce the peri-implant crestal bone resorption, which supports the long-term predictability of implant therapy.

Background. Acid etching prior to orthodontic bracket bonding may result in enamel wear or cracks following bracket removal. The manufacturer of Fuji Ortho LC glass-ionomer (GI) claims that it can bond brackets to wet unetched enamel. This study aimed to compare the bracket bond strength to etched and unetched enamel under dry and wet conditions.
Methods. In this in vitro study, 60 intact premolar teeth were randomly assigned to 6 groups (etched and dried, etched and moistened with distilled water, etched and moistened with saliva, unetched and dried, unetched and moistened with water, unetched and moistened with saliva). In all the groups, Leon 4 brackets were bonded to the enamel using Fuji Ortho LC GI. The teeth were immersed in distilled water at 37°C for 24 hours and subjected to shear loads at a crosshead speed of 5 mm/min in a Zwick machine for bond strength testing. Data were analyzed with ANOVA, Tukey test and independent t-test.
Results. The mean bond strength values in groups 1 (etched, dry), 2 (etched, moistened with water), 3 (etched, moistened with saliva), 4 (unetched, dry), 5 (unetched, moistened with water) and 6 (unetched, moistened with saliva) were 21.86, 16.46, 10.49, 8.12, 9.15 and 9.52 MPa, respectively. Significant differences in bond strength were detected between groups 1 and 2 and all the other groups (P 0.05).
Conclusion. Fuji Ortho LC GI provided adequate bond strength between brackets and enamel. To acquire higher bond strength, brackets must be bonded to etched and dried enamel.

Background. One of the problems with composite resin restorations is gap formation at resin‒tooth interface. The present study evaluated the effect of preheating cycles of silorane- and dimethacrylate-based composite resins on gap formation at the gingival margins of Class V restorations.
Methods. In this in vitro study, standard Class V cavities were prepared on the buccal surfaces of 48 bovine incisors. For restorative procedure, the samples were randomly divided into 2 groups based on the type of composite resin (group 1: di-methacrylate composite [Filtek Z250]; group 2: silorane composite [Filtek P90]) and each group was randomly divided into 2 subgroups based on the composite temperature (A: room temperature; B: after 40 preheating cycles up to 55°C). Marginal gaps were measured using a stereomicroscope at ×40 and analyzed with two-way ANOVA. Inter- and intra-group comparisons were analyzed with post-hoc Tukey tests. Significance level was defined at P Results. The maximum and minimum gaps were detected in groups 1-A and 2-B, respectively. The effects of composite resin type, preheating and interactive effect of these variables on gap formation were significant (P Conclusion. Gap formation at the gingival margins of Class V cavities decreased due to preheating of both composite resins. Preheating of silorane-based composites can result in the best marginal adaptation.

Background. Further studies on the adhesion properties of MTA-based materials seem necessary due to their growing use in endodontic treatment. This research aimed to assess the effect of retreatment on the bond strength of MTA-based (MTA Fillapex) and epoxy resin-based (AH Plus) sealers.
Methods. ProTaper rotary files were applied to prepare the root canals of 80 human mandibular premolars. Then, the roots were randomly divided intotwo groups of A (n=40) and B (n=40), which were obturated with gutta-percha and MTA Fillapex and AH Plus sealer, respectively. In both groups, the teeth were randomly subdivided into 2 subgroups. No retreatment was carried out in subgroups A1 and B1, while subgroups A2 and B2 were retreated with rotary files and a solvent. Then, a push-out test was performed on four 2-mm slices of each tooth at a distance of 2 mm from the coronal surface after two weeks of incubation. Data were analyzed with two-way ANOVA and statistical significance was set at P Results. Regardless of the procedure followed (P Conclusion. AH Plus sealer exhibited a higher bond strength compared to MTA Fillapex. Retreatment using rotary files and chloroform had no statistically significant effect on the bond strength of sealers evaluated in this study.

Hyperdontia or supernumerary teeth in both arches without any syndromic manifestation are extremely rare. Supernumerary teeth are commonly associated with Gardner’s syndrome, cleft lip and palate, cleidocranial dysplasia and trichorhinophalangeal syndrome. Five cases of non-syndromic multiple premolars of maxillary and mandibular arches in Indian patients are presented here. This case series reports three cases with multiple (9 in maximum), bilaterally impacted and erupted supernumerary teeth and two cases with supernumerary premolars in non-syndromic cases from Indian patients. Supernumerary teeth can be present in any region of the oral cavity. Although the occurrence of maxillary para-premolars is rare, radiological investigations play a major and decisive role in determining the management of such cases.

A case is reported of a 26-year-old blind man with hypodontia and multiple apparently underdeveloped impacted teeth. The patient reported that he had progressively developed visual impairment at the age of 11 years whence he became totally blind when he turned 12 years. The aim of this report is to open an academic and professional debate on the challenges of its definitive diagnosis and appropriate intervention.Blindness is not reported in any of the previously described syndromes; therefore, concurrent manifestation of “hypodontia, blindness, failure of eruption and digital lesions” can be proposed as a syndrome. However, in the absence of genetic studies, it is difficult to characterize this case with any one of the specifically documented syndromes; therefore, academic and professional discourse is suggested with regard to appropriate intervention.

Osteomas are benign bone tumors which arise from the cortex or medulla of craniofacial and jaw bones. They are usually asymptomatic or present as slow-growing painless masses. Larger lesions may present with aesthetic (facial asymmetry) and functional disturbances (jaw deviation, difficulty in breathing, pain, and sensory deficits). This paper highlights a case of solitary peripheral osteoma composed of a compact bony mass arising from the lower border of the mandible in an adult female patient. The lesion presented with discomfort during deglutition, which was attributed to impingement of muscles of the oral cavity floor, including the anterior belly of digastric muscle.

Mobius syndrome is a rare congenital disorder with the preliminary diagnostic criteria of congenital facial and abducent nerve palsy. Involvement of other cranial nerves, too, is common. Prevalence rate of this syndrome is approximately 1 in 100,000 neonates. It is of unknown etiology with sporadic occurrence. However, data regarding the occurrence rate in India is limited. Features such as orofacial malformations, limb defects, and musculoskeletal, behavioral, and cognitive abnormalities might be associated. A thorough evaluation to identify the condition and establishing an adequate treatment plan is of utmost important in this condition. We are reporting clinical and radiographic features of Mobius syndrome in two cases along with unusual findings of limb and neck deformity.

Background. The present study aimed to screen the knowledge and attitudes of dentists toward the use of informed consent forms prior to procedures involving operative dentistry.
Methods. A research tool containing questions (questionnaire) regarding the use of informed consent forms was developed. The questionnaire consisted of seven questions structured to screen the current practice in operative dentistry towards the use of informed consent forms.
Results. The questionnaires were distributed among 731 dentists, of which 179 returned them with answers. Sixty-seven dentists reported not using informed consent forms. The main reasons for not using informed consent forms were: having a complete dental record signed by the patient (67.2%) and having a good relation with patients (43.6%). The dentists who reported using informed consent forms revealed that they obtained them from other dentists and made their own modifica-tions (35.9%). Few dentists revealed contacting lawyers (1.7%) and experts in legal dentistry (0.9%) for the development of their informed consent forms.
Conclusion. A high number of dentists working in the field of operative dentistry behave according to the ethical stan-dards in the clinical practice, becoming unprotected against ethical and legal actions.