Journal of Dental School
Year:2013 | Volume:31 | Issue:3 (99)|Papers Count:10

Objective: Peri-implantitis is an irreversible inflammatory reaction in the soft and hard tissues around a functional implant. One of the treatment approaches of this disease includes smoothing and polishing the rough surface and removing threads on the implants using rotary instruments, which is called implantoplasty. Clinicians should perform implantoplasty with caution because it may raise the temperature of the implant body as well as the surrounding one. This study aimed to compare micromorphology and thermal changes resulting from different rotary instruments and piezoelectric devices after implantoplasty. Methods: Forty-eight Intra Lock fixture surfaces were processed in 60 seconds with six polishing procedures using 6,12 bladed carbide burs, 90, 30 urn mean-particles-size diamond burs, and piezosurgery inserts OT1 (grain size=91mm) and OPS (grain size =30mm). These instruments were applied in single or sequential procedures. Variations in temperature were recorded every S seconds. The roughness of treated surfaces was evaluated with a profilometer for Ra l , RzI (single polish procedures), Ra2, and Rz2 (sequential polishing procedures) parameters. Also, surfaces were observed using a field emission scanning electron microscope after each step of implantoplasty. Results: The piezosurgery group showed statistically significant differences when compared with the other two groups (maximum temperature 1.2°C). No statistically significant differences were observed between the carbide and diamond burs regarding the temperature changes and the temperature decreased from the start point in both groups. The mean Ra value in piezoelectric group (1.53±0.23) was significantly lower than diamond (2.45±0.04, p<0.05) and carbide (2.10±0.28, p<0.05) groups. Additionally, this value in the carbide group was significantly lower than that of the diamond group (p<0.05). Rzl value was significantly greater in diamond and carbide groups compared to piezoelectric group. The results revealed significant differences among the three groups concerning Rz2. The minimum Rz2 value was seen in piezoelectric group, while the diamond group showed the highest Rz2 parameter. Conclusion: This in vitro study showed that under suitable cooling conditions, implantoplasty with rotary and piezoelectric devices does not produce enough heat to damage the soft tissue or bone around the affected implant. The piezoelectric device produced smoother surfaces in single or sequence procedures compared to the burs and can be useful for implantoplasty.

Objective: Furcal perforation is an undesirable complication that may occur during root canal therapy and seriously compromises the prognosis of endodontic treatment. The prognosis of furcal perforation repair depends on the prevention of bacterial infection of the perforation site. Thus, use of a biocompatible material for complete sealing of the perforation site is critically important. This study aimed to compare the micro leakage of mineral trioxide aggregate (MTA) and octaca1cium phosphate (OCP) for furcal perforation repair.Methods: This experimental study was conducted on 70 human mandibular molars with divergent roots, intact furcation site and completely formed apices. The teeth were randomly divided into 4 groups of two experimental (n=30), one positive control and one negative control group (n=5). The furcation floor was then perforated. In the first and second experimental groups, furcation perforations were repaired with OCP and MT A, respectively. In the positive control group, the perforation was left untreated and in the negative control group no furcal perforation was created. The access cavity in all groups was filled with Cavit. The teeth were stored in 100% humidity for 48h. Root apices were sealed with sticky wax and the entire external surface of teeth except for 0.5 mm around the perforation site was covered with two coats of nail polish. The specimens were immersed in India ink for 4 days and then sectioned in half buccolingually. The sections were separated and dye penetration was evaluated using a stereomicroscope at 25X magnification. Obtained data were Janalyzed using independent t-test.Results: No micro leakage was observed in the negative control group. In the positive control group, the dye had completely penetrated into the walls. The amount of dye penetration was 1.64 and 1.22mm in the OCP and MT A groups, respectively. Statistical analysis of data revealed that the sealability ofMTA was significantly greater than that ofOCP (P<0.0001).Conclusion: OCP cannot be an acceptable alternative to MT A in terms of sealability.

Objective: Shear bond strength is an important property inherent to the durability of tooth-colored restorative materials namely composite resins. It has been years that halogen light sources have been used for polymerization of composite resins. In recent years Light Emitting Diodes (LED) have been introduced for this purpose. With respect to their longer bulb life, needless of a filter and no heat production, the demand for their use has increased. This study aimed to compare three different LED curing-lights with conventional Quartz Tungsten Halogen (QTH) lights to assess their effects on shear bond strength of composite to dentin.Methods: In this laboratory study, 60sound caries-free premolar teeth, after disinfection with sodium hypochlorite and cleaning with a scaler, were divided into four groups of 15. After the specimens had their dentin surface exposed with a metal disc, the composite restoration was done. The restorations in each group were done using Single Bond bonding agent and cured with the QTH light curing units and three different LED curing devices. Next, the strength of each bond was measured with an Instron Machine. The results were analyzed with one-way ANOV A and Tukey's test.Results: Analysis of the data with one-way ANOVA revealed statistically significant differences between the groups (P<0.05). The greatest bond strength related to the LED light in ramp mode with 114.68 Newtons (N) or 22.94 megapascals (MPa).The lowest related to the pulsed-LED with a mean of 70.35 N (l4.70 MPa). In pair wise comparison of the 4 groups with Tukey's test, all groups with the exception of QTH with a mean of 99 N(l9.80MPa) and the conventional LED with a mean of 86.78N (l7.35 MPa), had a significant difference (P<0.05).Conclusion: Our study showed that the use of LED light in ramp mode had better results compared to the QTH light source (control group) (P=0.38). Conventional LED light was comparable to the QTH light as well (P=0.169).

Background and Objectives: Attached gingival width (AGW) is an important marker for diagnosis of periodontal disease and normal gingival sulcus depth (GSD) is a sign of healthy periodontium. The aim of this study was to determine the AGW and GSD in3-15 year-olds with three dentition systems in Isfahan in 2001.Materials and Methods: A total of360 students (120 students in each system) eligible for this cross sectional study were randomly chosen from 30 schools and examined clinically. Data were registered in a questionnaire by two professional examiners. The GSD (the distance from the free gingival margin to the deepest part of the pocket) was measured by a probe. Keratinized gingiva (the distance between the attached gingiva and mucogingival junction) was measured by a vernier caliper or probe and the AGW was measured by subtracting the two amounts in primary and permanent dentition systems. These amounts were registered in a questionnaire and compared using ANOV A and Tukey's test.Results: The AGW in the primary, mixed and permanent dentition systems was 2.60±7.02, 2.56±7.23 and 2.73±1.3mm, respectively. The lingual surface of the posterior mandible had the greatest amount of attached gingiva in the three dentition systems. Also, the GSD in permanent dentition system in the anterior, middle and posterior areas of both jaws and in the buccal, lingual and palatal surfaces was more than in the primary dentition system.Conclusion: Based on the results, the AGW in permanent dentition was more than in primary and mixed dentition systems. The AGW increases with age and is not affected by gender. Also, the AGW was less in the lower jaw compared to the upper jaw and was more in lingual surface than in buccal surface.

Objective: Various factors affect dental caries and impact the patterns of dental care. A few studies have been conducted to identify these factors from the perspectives of students. This study aimed to explore factors influencing dental caries from students' perspectives.Methods: A qualitative design using content analysis approach was conducted to collect the perspectives of 18 Iranian students who were studying in 8 guidance schools. They were chosen through purposive sampling. Semi- structured private interviews and focus groups were held for data gathering. The tape-recorded interviews were transcribed verbatim and analyzed using an inductive content analysis approach. In order to support the validity and rigor of the data, different trustworthiness criteria such as acceptability, confirm ability and transferability were considered.Results: During data analysis, four main categories were developed: "difficult conditions of care", "disability in caring", "uncontrollability of dental caries" and "intangible sense of the factors causing dental caries". The participants more emphasized their own experiences about having insufficient dental-oral care, not paying attention to oral health, dental fear and the lack of both knowledge and competency regarding this issue.Conclusion: The findings of this study revealed factors influencing dental caries from students' perspectives and emphasized the roles of individual, parent, dentist and community in this respect. The findings of this study can be considered to be a valuable basis to design oral health interventions. However, more studies are required to improve our understanding of dental fear and denote barriers and social beliefs pertinent to oral health in different groups of students.

Objective: Mechanical plaque removal namely tooth brushing is the most commonly used oral hygiene technique. Efficacy of tooth brushing is influenced by the design and shape of toothbrush. This study aimed to compare the efficacy of two common Iranian toothbrushes with a foreign made one in plaque removal.Methods: This clinical trial was conducted on 30 female dental students in Babol University, School of Dentistry using simple randomized sampling. Oral B Cross Action(Germany), Panberes Cross Action and Panberes Classic (Iran) toothbrushes were compared. Students were asked not to brush their teeth for 24 hours before the first visit. At the first visit, subjects received oral prophylactic procedures and the baseline plaque index was recorded before brushing for all subjects using 0' Leary plaque index. In order to match the conditions, Bass tooth brushing technique was instructed to subjects. Students were then randomly divided into 3 groups of 10. The subjects were provided with the three toothbrushes for use in the first, second and third weeks. The plaque index was recorded after using each toothbrush for one week. Paired t-test was used to compare the efficacy of toothbrushes in plaque removal in the same subject while ANOV A was applied for the comparison between the three toothbrushes.Results: Significant reductions were observed in plaque index after using each toothbrush. Plaque index reduction was the highest for Oral B Cross Action and the lowest for Panberes Classic (P=0.001). Oral B Cross Action and a significant difference with Panberes Classic in mean plaque index reduction (P=0.018). Panberes Cross Action and Oral B Cross Action were not significantly different in this respect (P=0=797).Conclusion: Oral B Cross Action and Panberes Cross Action were not significantly different in terms of plaque index reduction. However, the mentioned two toothbrushes had a significant difference in this respect with Panberes Classic.

Objective: Successful bonding of a dental implant to bone, which was referred to as osseointegration by Branernark has been well documented. However, long-term prognosis of an implant depends on adequate maintenance and long-term care. An effective maintenance program is required to preserve the health of peri-implant tissues. Several techniques have been suggested for this purpose; but it is not clear which is more efficient.Review of Literature: This review evaluates the literature regarding implant care and factors affecting the peri-implant soft tissue and describes the required measures for assessment of peri- implant status and treatment of reversible peri-implant diseases.Conclusion: Data shows that several measures can be taken to maintain the health of peri-implant tissue and ensure the long-term prognosis of dental implants.

Objective: Citation analysis is a bibliometric method used for the calculation of the mean number of citations and detection of highly cited references, frequency distribution of citations in different languages, update rate, efficacy of resources and number of core journals of a scientific domain. This process elucidates the information needs of researchers in a specific realm of science and enhances the knowledge of the authorities and librarians to provide efficient information sources and use the budget for providing a rich collection of scientific materials. This study aimed to perform a citation analysis on dental journals.Methods: A checklist was prepared including the type of cited material (article, book, thesis, etc.), publication year, language, type of access (consortium, free, none) and if accessible through the consortium, name of the database through which the article can be accessed. Data were analyzed using SPSS software. Using Bradford's law of dispersal of publications, the core journals in the field of dentistry were specified.Results: The authorities must consider the core journals in each scientific domain when making a decision on purchasing subscription or extending a contract with databases in order to be more successful in obviating the information needs of researchers.Conclusion: Authorities have to consider the core journals in each field when deciding on purchasing subscription or extending the contract with databases in order to be more successful in obviating the scientific needs of researchers.