Dental Research Journal
Year:2011 | Volume:8 | Issue:1|Papers Count:10

Background: There is a controversy about exact time of bone healing. The aim of this study was evaluation of bone formation and change of density after mandibular third molar extraction.Methods: Radiographs were taken from 16 empty tooth sockets immediately after extraction of mandibular third molars and 2, 4 and 6 months later under similar condition. The radiographs were digitized and the density numbers of pixels were calculated. Then, socket and neighbor regions were compared using Photoshop software. Three expert observers evaluated and compared the radiographs by the longitudinal radiographic assessment (LRA) method. Paired t-test and McNemar test were used to analyze the data and investigate the inter-observer reliability, respectively.Results: Analysis of the quantitative digital subtraction radiography (QDSR) data indicated that the difference between the digital numbers of interest points and reference points has been decreased during the months 2, 4 and 6 but the difference between the month 4 and 6 was not significant. The alternative method indicated that the mean digital numbers in the socket within 0and 2 months period was less than 128 and within 4 and 6 months was more than 128. In evaluation of LRA method, lamina dura started to change gradually in month 2 and it might disappear completely after 6 months.Conclusion: Both QDSR and LRA methods can be used in evaluation of the rate of bone formation in the tooth socket but the former is more precise.

Background: An increase in surface roughness of ceramics may decrease strength and affect the clinical success of ceramic restorations. However, little is known about the effect of acidic agents on ceramic restorations. The aim of this study was to evaluate the surface roughness of dental ceramics after being immersed in acidic agents.Methods: Eighty-three ceramic disk specimens (12.0 mm in diameter and 2.0 mm in thickness) were made from four types of ceramics (VMK 95, Vitadur Alpha, IPS Empress Esthetic, and IPS e. max Ceram). Baseline data of surface roughness were recorded by profilometer. The specimens were then immersed in acidic agents (citrate buffer solution, pineapple juice and green mango juice) and deionized water (control) at 37oC for 168 hours. One group was immersed in 4% acetic acid at 80oC for 168 hours. After immersion, surface roughness was evaluated by a profilometer at intervals of 24, 96, and 168 hours. Surface characteristics of specimens were studied using scanning electron microscopy (SEM). Data were analyzed using two-way repeated ANOVA and Tukey’s multiple comparisons (a=0.05).Results: For all studied ceramics, all surface roughness parameters were significantly increased after 168 hours immersion in all acidic agents (P<0.05). After 168 hours in 4% acetic acid, there were significant differences for all roughness parameters from other acidic agents of all evaluated ceramics. Among all studied ceramics, Vitadur Alpha showed significantly the greatest values of all surface roughness parameters after immersion in 4% acetic acid (P<0.001). SEM photomicrographs also presented surface destruction of ceramics in varying degrees.Conclusion: Acidic agents used in this study negatively affected the surface of ceramic materials. This should be considered when restoring the eroded tooth with ceramic restorations in patients who have a high risk of erosive conditions.

Background: Bleaching the discoloured teeth may affect the tooth/composite interface. The aim of this in vitro experimental study was to evaluate the effect of vital tooth bleaching on microleakage of existent class V composite resin restorations bonded with three dental bonding agents.Methods: Class V cavities were prepared on buccal surfaces of 72 intact, extracted human anterior teeth with gingival margins in dentin and occlusal margins in enamel, and randomly divided into 3 groups. Cavities in the three groups were treated with Scotch bond Multi-Purpose, a total etch system and Prompt L-Pop and iBond, two self-etch adhesives. All teeth were restored with Z250 resin composite material and thermo-cycled. Each group was equally divided into the control and the bleached subgroups (n=12). The bleached subgroups were bleached with 15% carbamide peroxide gel for 8 hours a day for 15 days. Microleakage scores were evaluated on the incisal and cervical walls. Data were analyzed using Kruskal-Wallis, Mann-Whitney and Bonferroni post-hoc tests (a=0.05).Results: Bleaching with carbamide peroxide gel significantly increased the microleakage of composite restorations in Prompt L-Pop group at dentinal walls (P=0.001). Bleaching had no effect on microleakage of restorations in the Scotch bond Multi-Purpose and iBond groups.Conclusion: Vital tooth bleaching with carbamide peroxide gel has an adverse effect on marginal seal of dentinal walls of existent composite resin restorations bonded with prompt L-Pop self-etch adhesive.

Background: The final objective of root canal therapy is to create a hermetic seal along the length of the root canal system. For this purpose, many methods and materials have been introduced. The purpose of this study was to compare the apical microleakage in a new obturation technique (true-tug-back) with two other obturation techniques (lateral condensation and chloroform dip technique).Methods: In this in vitro study 102 single canal teeth were selected. The crowns were removed, and the canals were prepared using step-back technique. The master apical file was K-file #40. The teeth were divided into 3 experimental groups of 32 teeth. First group were obturated with lateral condensation technique and second group with chloroform dip technique and the third group with true-tug-back technique. Six teeth were used as control group. The teeth were placed in incubator at 100% humidity and 37oc for three days. The roots of the teeth were coated with two layers of nail varnish except for the apical 2 millimeter.Teeth were placed in Methylene blue 2% for one week. The teeth were sectioned vertically and the depth of maximum dye penetration for each tooth was recorded by stereomicroscope.Data were analyzed using ANOVA and Dunkan test.Results: The mean liner dye penetration differences between lateral condensation group (6.88 ± 4.06 mm) and chloroform dip technique group (7.16 ± 3.37 mm) were not statistically significant (P=0.719). The differences between true-tug-back group (3.15 ± 0.52 mm) and two other groups were statistically significant (P<0.001).Conclusion: The results of this study showed that the true-tug-back technique can improve apical seal. Further studies are needed for this purpose.

Background: The aim of this study was to compare the antibacterial efficacy of endemic Satureja Khuzistanica Jamzad (SKJ) essential oil as root canal irrigation versus 2.5% sodium hypochlorite and 2% chlorhexidine gluconate.Methods: In current in vitro experimental study, fifty four single-rooted teeth were randomly divided into 6 groups of 9 samples: 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate (CHX), 0.31 mg/ml SKJ, 0.62 mg/ml SKJ, positive and negative controls. Each tooth was instrumented, sealed and autoclaved. Then, test groups were inoculated with E. faecalis, treated with irrigation solution and viable bacterial counts in intracanal dentin chips were determined. Utilizing SPSS 18 software, collected data were analyzed by Kruskal-Wallis one way analysis of variance (P=0.05).Results: 99.94 % and 99.50% reduction in bacteria load after 5 min treatment with NaOCl and CHX were detected, respectively. Similarly, 99.97% and 99.96% reduction in bacterial counts were observed after 5 min application of 0.62 mg/ml and 0.31 mg/ml SKJ essential. No significant differences were detected among the four irrigation solutions (P=0.755).Conclusion: SKJ essential oil with the minimum inhibitory concentration (MIC) of 0.31 mg/ml could be an effective antibacterial irrigation solution.

Background: Comparing continuous films taken at different timescales is a way to study the alveolar bone changes around the implant over time. One of the important concerns in quantitative analysis of the alveolar bone changes over the time is to reduce variations in the X-ray imaging geometry and image density.Methods: Using a modified XCP film holder together with the bite recording material, parallel periapical radiographs were taken from the implants placements of 16 patients in four steps. Densities of radiographs were measured in a conventional way using the video densitometry device. The same films were also scanned, sequential radiographic density of each patient was homogenised and the density was measured. Density changes obtained in both methods were compared. The data were evaluated using ANOVA, paired t-test and Pearson correlation (a=0.05).Results: In the conventional method of densitometry, the average densities were as follows: before operation 1.0044, after one week 0.9600, after one month 0.9469 and after three months 0.9398.Also, in the standard method of densitometry, the average densities were as follows: before operation 111.7013, after one week 113.4225, after one month 119.4075 and after three months 131.1162. Average density in conventional densitometry were not significantly different in various time stages (P=0.395). But, the standard densitometry method showed a significant difference (P=0.001).Conclusion: The average density obtained at different stages in the standard densitometry showed a gradual increase in the bone density in the entire process. Standardising the patient’s consecutive radiographic images is essential for quantitative measurements over the time.

The actual relationship between periodontal and pulpal disease was first described by Simring and Goldberg in 1964. Since then, the term "perio-endo" lesion has been used to describe lesions due to inflammatory products found in varying degrees in both the periodontium and the pulpal tissues. The pulp and periodontium have embryonic, anatomic and functional inter-relationships. The simultaneous existence of pulpal problems and inflammatory periodontal disease can complicate diagnosis and treatment planning. A perio-endo lesion can have a varied pathogenesis which ranges from quite simple to relatively complex one. Knowledge of these disease processes is essential in coming to the correct diagnosis. This is achievable by careful history taking, examination and the use of special tests. The prognosis and treatment of each endodontic-periodontal disease type varies. Primary periodontal disease with secondary endodontic involvement and true combined endodontic-periodontal diseases require both endodontic and periodontal therapies. The prognosis of these cases depends on the severity of periodontal disease and the response to periodontal treatment. This enables the operator to construct a suitable treatment plan where unnecessary, prolonged or even detrimental treatment is avoided.

Lipoma, a benign tumor of adipose tissue is one of the most common benign neoplasms of the body.However, its occurrence in oral cavity is very rare. It accounts for 1 to 4% of benign neoplasms of mouth affecting predominantly the buccal mucosa, floor of mouth and tongue. We report three cases of intraoral lipoma, two in buccal mucosa and one in labial mucosa. An excisional biopsy was performed and histopathological examination revealed proliferation of mature adipocytes arranged in lobules and separated by fibrous septa. After 3 years follow up, the patients showed no signs of recurrence.

Nevus of Ota is a condition wherein the typical pattern of the bluish black pigmentation is noticed along with the cutaneous distribution of the trigeminal nerve. This condition is most prevalent in Japanese population but comparatively rare among Indians. We report a case of 23-year-old female presented with unilateral pigmented areas over the skin of forehead, malar area, ear and periorbital area.Blackish-blue pigmented areas were also noticed on the sclera. Brownish-black diffuse pigmented areas were also noticed on the buccal mucosa of the same side. The presence of pigmentation on the skin over pinna and oral pigmentation made our case a rare incidence. Oral pigmentations associated with nevus of Ota especially on the buccal mucosa have rarely been reported in the past.