Journal of Dentistry of Tehran University of Medical Sciences最新文献

Objectives: Following tooth extraction, soft and hard tissue alterations occur; Different factors can affect this process. The objective of this study was to determine the effect of gap filling on buccal alveolar crestal bone level after immediate implant placement after 4- to 6-month observation period.

Materials and methods: This randomized clinical trial was performed on 20 patients (mean age of 38.8 years) requiring tooth extraction in a total of 27 areas in the anterior maxilla. The treatment strategy was as follows: atraumatic flapless tooth extraction, implant placement, insertion of a graft (test group) or no material (control group) between the implant and the socket wall, connection healing abutment placement and suturing the area. Clinical and cone beam computed tomographic examinations were performed before implant placement (baseline), 24 hours after surgery and 4-6 months (T2) after implant placement, to assess the buccal plate height (BH) and implant complications.

Results: After 4 months of healing, a reduction in different bone measurements was noticed in the two groups. No statistically significant differences were assessed in bone height measurements between the test and control groups at different time points. The study demonstrated that immediate implantation resulted in 1.30 and 1.66 mm reduction in buccal bone plate in the test and control groups, respectively.

Conclusions: The study demonstrated that immediate implantation in the extraction socket together with xenograft failed to prevent bone resorption.

Multilevel analysis which was primarily introduced to deal with hierarchical data was later applied extensively for research in other fields of science and not only for nested data, but also for repeated measurements or clustered trials. This method of statistical analysis was applied in dental studies in the 1991 for the first time but despite its value for data analysis in dental studies, its application for dental studies remains limited until now. This manuscript reviews the applications of this method in dental studies.

Objectives: The aim of this study was to determine the impact of fixture location and crown restoration on the accuracy of linear measurements by two cone-beam computed tomography (CBCT) systems.

Materials and methods: Six dental implants were inserted in a dry human mandible in two stages. CBCT images were obtained in each stage by Alphard VEGA 3030 and Promax 3D Max systems. Imaging procedures were repeated after metallic crown placement. Two observers measured the alveolar height and width using five radiopaque markers. Values were compared to the same measurements made on initial images (prior to implant insertion) using t-test. The linear regression test was used to evaluate the effect of implant location on the accuracy of linear measurements.

Results: The impact of fixture and fixture-crown combination on the accuracy of linear measurements of height (t = -5.2, P=0.0001 and t=-5.98, P<0.0001, respectively) and width (t=-3.42, P=0.004 and t= -2.7, P=0.015, respectively) was significantly underestimated. Metal crowns had no significant effect on measurements of bone height and width (t=-1.38, P=0.19 and t=0, P=1.00, respectively). Although both systems showed some underestimations, Promax 3D Max underestimated bone width significantly more than the other system (Alphard VEGA 3030=- 0.51mm and Promax 3D Max=-0.80). Regarding implant location, the measurements in the canine sites were found to be more accurate than the region between adjacent implants.

Conclusions: CBCT is an accurate and reproducible system for dental implant follow-up examinations. Metal artifacts can lead to underestimation of measurements. However, this was not statistically significant in our study.

Objectives: Streptococcus mutans (S. mutans) is a cariogenic microorganism. The restorative materials which harbor a biofilm with high levels of S. mutans can accelerate the occurrence of dental caries. The purpose of this study was to evaluate the influence of different restorative materials on S. mutans colonization in a simple in-vitro biofilm formation model.

Materials and methods: Thirteen discs of each material (nanohybrid resin composite, microhybrid resin composite, and amalgam) were prepared, polished, and sterilized in a gamma radiation chamber. The saliva-free specimens were exposed to the S. mutans bacterial suspension (0.5 McFarland) and were incubated for 4 hours. Afterwards, the specimens were rinsed and sonicated in normal saline. 10μl of the obtained suspension was cultured in a sterile blood agar medium. After 24 hours, the number of colony forming units (CFU) of S. mutans was counted. A sterility test control was considered for each group of materials. The data were analyzed by one-way ANOVA at 5% significance level.

Results: The means and standard deviations of the logarithmic values of the colonies on the surfaces of amalgam, microhybrid, and nanohybrid resin composites were equal to 3.76±0.64, 3.91±0.52 and 3.34±0.74, respectively.

Conclusions: There were no significant differences between the restorative materials in terms of S. mutans adhesion rate. The evaluated resin composites showed comparable numbers of CFUs, which could imply the importance of the polishing procedures.

It is estimated that one-third of the people with refractory epilepsy suffer from obstructive sleep apnea (OSA). In a patient presenting with OSA symptoms and epilepsy, removing a portion of the soft palate (uvulopalatoplasty) can be considered the treatment of choice for eliminating the OSA and decreasing the seizures. Here, we report the results of our surgical approach by which the patient's problems completely resolved, and we observed no symptoms of OSA or epilepsy after the surgery. After 10 years of follow-up, the patient is seizure-free and does not need any antiepileptic drugs.

Objectives: Graft-versus-host disease (GVHD) is among the most frequent complications of allogeneic hematopoietic stem cell transplantation (HSCT). GVHD has several clinical manifestations in the oral cavity, including painful desquamative erythema, ulcerative mucosal lesions, and lichenoid lesions. The patients presenting with oral GVHD complain of oral sensitivity, pain, dysgeusia, and xerostomia. The treatment of oral GVHD includes a proper systemic therapy combined with a good oral hygiene and the use of local and topical steroids. Corticosteroids and immunosuppressants are used for the treatment of chronic oral GVHD; however, they are associated with different complications. Evidence shows that curcumin has anti-inflammatory and antioxidative properties. The treatment of lichen planus and oral mucositis with curcumin has been successful. This study aimed to compare the efficacy of topical curcumin in Orabase and triamcinolone in Orabase in the patients affected by oral GVHD.

Materials and methods: Twenty-six patients presenting with oral GVHD were randomly divided into two groups of 13 using block randomization. The control group used triamcinolone in Orabase, and the case group received curcumin in Orabase.

Results: The two groups were not significantly different in terms of the alleviated severity of the lesions at the end of the treatment (P=0.052). The comparison of the pain score via the visual analog scale (VAS) at the onset of the treatment and at days 14 and 28 (completion of the treatment) showed no significant difference between the two groups (P>0.05).

Conclusions: Curcumin has comparable efficacy to that of triamcinolone and may be prescribed for the patients presenting with oral GVHD.

Objectives: About two-thirds of cancer patients undergo radiotherapy. Oral mucositis represents a major complication of radiotherapy, causing morbidity and mortality and decreasing the quality of life of patients. This study aimed to assess the preventive effect of Glycyrrhiza aqueous extract on oral mucositis in cancer patients under head and neck radiotherapy.

Materials and methods: In this double-blind clinical trial, 37 head and neck cancer patients were divided into intervention (n=19) group receiving Glycyrrhiza aqueous extract and control (n=18) group receiving placebo. Patients in the test group used Glycyrrhiza aqueous extract topically twice a day from the first day of starting radiotherapy until the end of the second week. Patients were examined in the first day of radiotherapy for any type of wound before treatment and those with oral ulcers before radiotherapy were excluded from the study. The grade of mucositis was determined using the classification by the World Health Organization. ANCOVA was performed to assess any difference between the two groups with regard to oral mucosal irritation and wound size after the intervention while controlling for the covariates such as sex and age.

Results: Significant differences were found in the maximum grade of mucositis and oral mucosal irritation between the intervention and control groups (P<0.001).

Conclusions: This study showed that aqueous extract of Glycyrrhiza can be effective for decreasing the severity of oral mucositis in head and neck cancer patients undergoing radiotherapy.

Subcondylar fractures are common in the maxillofacial region following direct trauma to the mandibular ramus. The literature is replete with articles written on the treatment of subcondylar fractures, encompassing a plethora of various surgical approaches; however, the best treatment procedure has remained controversial. Such fractures are either treated by open reduction with internal fixation or closed reduction with maxillomandibular fixation. In this article, we describe a new surgical method for treatment of subcondylar fractures.

Objectives: The purpose of this study was to investigate the effect of different types of toothpaste on the frictional resistance between stainless steel brackets and archwires.

Materials and methods: Ninety stainless steel orthodontic brackets with stainless steel wires were bonded to bovine teeth and were divided into 6 groups for application of the following toothpastes: Colgate® Total® Advanced Whitening, Colgate® Total® Pro Gum Health, Colgate® Anticavity, Ortho.Kin®, and Sunstar GUM® Ortho toothpastes. No toothpaste was applied in the control group. Each group was brushed by a brushing machine with the use of the designated solution for 4.5 minutes. The frictional force was measured in a universal testing machine with a crosshead speed of 10 mm/minute over a 5-mm archwire. Data were analyzed using one-way analysis of variance (ANOVA) at the 0.05 significance level.

Results: The frictional resistance values of Ortho.Kin® and GUM® Ortho toothpastes and the control group were not significantly different (P>0.05). However, there were significant differences between the frictional resistance values of Colgate® Total® Pro Gum Health and Colgate® Anticavity toothpastes with that of the control group (P<0.05). The highest and lowest frictional resistance values were related to Colgate® Total® Pro Gum Health toothpaste and the control group, respectively.

Conclusions: Among the evaluated toothpastes, the orthodontic toothpastes did not increase the frictional resistance between the orthodontic stainless steel brackets and wires.

Objectives: This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-galliumgarnet (Er,Cr:YSGG) laser and the conventional acid-etching technique.

Materials and methods: This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30). The teeth in group A were etched with 37% phosphoric acid gel, while the teeth in group B were subjected to Er,Cr:YSGG laser irradiation (gold handpiece, MZ8 tip, 50Hz, 4.5W, 60μs, 80% water and 60% air). Orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. The samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. Independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. Levene's test was applied to assess the equality of variances.

Results: No significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (P>0.05).

Conclusions: Despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions), Er,Cr:YSGG laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding.