Vol 9, No 2 (2012)
Proceeding Abstracts
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Tramadol is a synthetic analgesic of opioids which has more flexible mechanisms of action than typical opioids. Since it has been reported in previous study that typical opioids like morphine can affect the bone homeostasis, it is worthwhile to examine the effects of tramadol on tooth movement. In this study we investigated effects of tramadol on orthodontic tooth movement in rats.30 male wistar rats were selected and received orthodontic appliance. 3 groups were designed based on the substance that they received daily injections of during a 2-week orthodontic treatment. 1. Control group with no injection.2.Control group with normal saline injection.3. the tramadol group. After the two-week treatment period the amount of tooth movement were measured in all the groups. Also the histological analysis was performed assessing the root resorption, osteoclasts numbers and bone resorption.The amount of tooth movement was not significantl in the tramadol group comparing to the other groups (P>0.05).The results of 3 histological parameters (amount of root resorption, osteoclastic numbers and bone resorption) were statistically insignificant (P>0.05).Tramadol as an atypical opioid does not interfere with the process of bone remodeling and tooth movement in rat. Tramadol does not affect osteoclastic activity and bone resorption and it does not cause to change the resulted root resorption either.
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Retention after orthodontic treatment is still an important part of the treatment. Splints are considered as an alternative for removable retainers. The main goal of this study was to assess splinting biomechanically.Three dimensional finite element models (3D) were designed of a mandibular anterior segment which included six anterior teeth with their supporting tissues (model 1 as control) and with a bonded lingual fixed retainer in the two other models. The wire cross section was round (0.016") in model 2 and rectangular (0.016" × 0.022") in model 3. The models were designed in Solid Works 2006 and analyzed in ANSYS Workbench Ver. 11.0 SolidWorks Incisors were loaded with a vertical force of 187 N. PDL stress and tooth displacements were evaluated.The numeric findings showed an increase after splinting in the central incisors [2.42 MPa to 4.57 MPa (round) and 16.66 (rectangular) MPa] in biting with four incisors. Biting with two incisors decreased the stress after splinting [2.42 MPa to 1.7 MPa (round wire) and 1.77 MPa (rectangular wire)]. In lateral movement, all teeth showed an increased stress except for the working side canine.Splinted cases (with round or rectangular wires) can benefit from stress redistribution when biting small food particles and in lateral movement.
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Microleakage is a major factor affecting longevity of composite restorations. This study evaluated the effect of polymerization mode of bonding agent on microleakage of composite restorations.Forty-eight Class V cavities were prepared on buccal and lingual surfaces of 24 extracted human premolars. Occlusal and gingival margins were placed in the enamel and dentin, respectively. Teeth were divided into four groups as follows: Group I: Optibond Solo Plus (light-cured); Group II: Optibond Solo Plus (dual-cured); Group III: Prime & Bond NT (light-cured), Group IV: Prime & Bond NT (dual-cured). Teeth were restored using Z250 composite in three increments. After polishing the restorations, samples were thermocycled for 1000 cycles and stored in distilled water for 3 months. Then they were placed in 2% fuchsine solution for 48 hours. The samples were sectioned longitudinally and evaluated for microleakage under a stereomicroscope at ×40 magnification. Dye penetration was scored on a 0-3 ordinal scale. Data were analyzed using Kruskal-Wallis, Bonferroni and Wilcoxon signed ranks test.Microleakage was significantly lower in enamel margins compared to dentin margins (P<0.05); multiple comparisons by Bonferroni tests revealed that the only factor with significant effect on leakage of the restoration is location of the restoration margin. Mode of adhesive polymerization had no significant influence on microleakage (P>0.05). Prime & Bond NT had less microleakage compared to Optibond SoloPlus, but the difference was not significant (P>0.05).There was no difference in the amount of microleakage in Class V composite restorations using light-cured and dual-cured bonding systems. Dentinal margins of restorations exhibited more microleakage than enamel margins.
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Radiographic evaluation of the third molar tooth to determine its position and degree of development is an important part in diagnosis and treatment planning, as well as in forensic dentistry procedures. The objective was to investigate the developmental stages of third molars in relation to chronologic age, gender and location (maxillary/mandibular) in an Iranian population.The data were collected in departments of pediatric dentistry and orthodontics, Tehran Faculty of Dentistry and four private offices. Three calibrated observers visited the centers to examine panoramic radiographs and corresponded patients documents in each age cohort in the range of 5- to-25-years old. Data were analyzed by Generalized Estimating Equation (GEE) in the linear mode and exchangeable correlation structure. The significance level was defined as 0.05.The mean age of emerging third molars' follicle was 9.29±1.65 years. Early calcification was seen at the mean age of 10.28±1.66 years. The GEE model controlling for age, gender and tooth location (maxillary/mandibular) revealed that besides age (β=0.43, p<0.001), the tooth location had association with the developmental stage (β=0.11, p<0.001) so that maxillary teeth were prior in calcification stages, but no relationship between gender and developmental stages was seen (β=0.03, p=0.69).Maxillary teeth were ahead of mandibular teeth in calcification stages with no gender difference. The present study may provide a reference for oral surgeons, pediatric dentists and orthodontists practicing in Iran and may have implications for the neighboring countries especially those with Caucasian populations.
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The objective of this study was to evaluate the effect of Accell Connexus(®) on the quality and rate of healing in experimental defects of rabbit calvarium compared to Bio-Oss®.Twelve 2.5-3.5 kg weighing New Zealand white rabbits were used. Three defects (3×6 mm) were created in the cranium of the animals subsequently filled with Accell Connexus(®), Bio-Oss® or served as controls. The animals were sacrificed four, six and eight weeks postoperatively and the histology blocks were studied in terms of inflammation, trabeculation thickness, bone type regeneration, foreign body and remained biomaterial by light microscope. The data were subject to Mann-Whitney U test.Increased inflammatory reaction, foreign body reaction, delayed bone formation and lower rate of ossification were observed in DBM-filled defects compared to Bio-Oss® or controls. However, no significant differences were observed in bone formation between Bio-Oss®, Accell Connexus(®) and control specimens in the three time intervals. Furthermore, no significant differences were noted between Bio-Oss® and control groups.Accell Connexus(®) showeda lower rate of ossification and bone healing compared to Bio-Oss® or controlgroups. Other studies in this field seem necessary.
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This study addresses the question of whether conservative methods of restoration may be applied efficaciously in permanent posterior teeth with proximal lesions and intact occlusal preventive resin restoration (PRR). The purpose of the present study was to assess the microleakage at amalgam-composite interface and composite-composite interface in permanent tooth with PRR.Thirty-five premolar teeth extracted for orthodontic reasons were selected. The occlusal surfaces were sealed as preventive resin restoration. Then the teeth were stored in incubator for 6 months. After this period, two single boxes were prepared in mesial and distal surfaces in each tooth and filled with amalgam. Another class I composite restoration was prepared in occlusal surface in contact with the first PRR. Then samples were thermocycled and marginal leakage was assessed by the degree of dye penetration on sections of the restored teeth. Friedman and Wilcoxon signed-rank tests served for statistical analyses.In 51.4% of amalgam-composite interfaces the dye reached the pulpal wall. The corresponded figures for amalgam-tooth and composite-composite interfaces were 31.4% and 14.3%, respectively. The differences in microleakage among the three interfaces were statistically significant (P<0.05).In the teeth restored with PRR technique, restoring proximal lesions with a conservative technique may lead to favorable results concerning microleakage.
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Age and tooth loss are expected to have a complex relationship with oral health-related quality of life. So the purpose of this study was to explain the impact of age and tooth loss on oral health-related quality of life using the short form 14-item oral health impact profile (OHIP-14) among two population samples of Gujarat and Rajasthan.A cross-sectional questionnaire-based survey was conducted among 1441 subjects collected from two major cities of Gujarat and Rajasthan. Both questionnaire approaches using OHIP-14 scale and clinical examination were conducted in accordance with WHO criteria using type III procedure on the same day. Chi square test, ANOVA and stepwise multiple regression analysis were applied using SPSS software version 15.0.With the increase of age, OHIP mean score in both states increased, but that among Rajasthan state was higher, depicting poor oral health. Whereas, in the remaining 23-27 number of teeth both states showed higher OHIP mean, however again the score was much higher among Rajasthan subjects showing worse oral hygiene. Hence, overall all mean OHIP score for Gujarat was lower indicating good oral health; whereas, that among Rajasthan was higher indicating poor oral health-related quality of life.Both age and tooth loss are associated with each other, but they have an independent effect on the oral health-related quality of life. Thus, all studied populations with complete natural dentition showed good oral health-related quality of life.
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It is proved that acidic soft drinks that are commonly used, have an adverse effect on dental structures, and may deteriorate oral heath of our patients and orthodontic appliances. The aim of this study was to compare the effect of yoghurt drink with other soft drinks on the shear bond strength of orthodontic brackets.Seventy-five first premolar teeth extracted for orthodontic purposes were selected and standard twin metal brackets were bonded on the center of buccal surface with No-Mix composite. The teeth were thermocycled for 625 cycles and randomly divided into five groups of artificial saliva, carbonated yoghurt drink with lactic acid base, non-carbonated yoghurt drink with lactic acid base, 7 up with citric acid base and Pepsi with phosphoric acid base. In all groups, the teeth were immersed in liquid for five-minute sessions three times with equal intervening intervals for 3 months. SBS was measured by a universal testing machine with a speed of 0.5mm/min. Data was analyzed statistically by one-way ANOVA.The results showed that mean values for the shear bond strength of carbonated yoghurt drinks, non-carbonated yoghurt drinks, 7up and Pepsi groups were 12.98(±2.95), 13.26(±4.00), 16.11(±4.89), 14.73(±5.10), respectively. There was no statistically significant difference among the groups (P-value= 0.238)Soft drinks used in this study did not decrease the bond strength of the brackets bonded with this specific type of composite.
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Calcium hydroxide is the most widely used intracanal medicament in endodontics, which should be removed prior to permanent root canal filling to minimize its intervention with the bonding of endodontic sealers. This ex-vivo study aimed to evaluate the effect of pretreatment with calcium hydroxide on the bond strength of Resilon/Epiphany self etch (SE) to the radicular dentin after removing the calcium hydroxide by hand file or ultrasonic methods.Thirty-six single-rooted human extracted teeth were used in this study. After root canal preparation, the teeth were divided into three groups. In group 1, as the control, no pretreatment was performed; while in groups 2 and 3, this was carried out using calcium hydroxide paste. After one week, the paste was removed with hand stainless steel K-files in group 2 and ultrasonic instrumentation in group 3. All samples were obturated with Resilon/Epiphany SE. One-millimeter slices of mid-root dentin were prepared for the push-out test (14 slices per group). After the bond strength was assessed, the failure modes were examined. The data were analyzed using one-way ANOVA and Dunnett Post Hoc tests.Group 2 significantly showed the lowest bond strength (0.947 ± 0.47) (P = 0.01). No significant differences were found between the control group (2.32 ± 1.43) and group 3 (1.78 ± 1.04) (P = 0.01).Under the conditions of this ex vivo study, calcium hydroxide as the intracanal medicament and its removal using hand instrumentation adversely affected the bond strength of Resilon/Epiphany SE.
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Bacterial leakage and root fractures are the most important reasons of root canal treatment failure. Due to the lack of adhesion of gutta percha to the canal walls, Resilon has been introduced as a root-filling material able to bond to the root walls. Metal posts may predispose the tooth walls to oblique and vertical fracture which usually leads to tooth loss; whereas, fiber posts may reinforce the remaining tooth structure. The purpose of this study was to compare the effect of Resilon and gutta-percha on the fracture resistance of root canal following restoring with quartz fiber posts.Forty-four maxillary incisor root canals were chemo-mechanically prepared, then randomly divided into three groups: 1-Control group (n=20), 2-Experimental group (n=20) and a negative control group (n=4). Root filled teeth were restored with quartz fiber posts and composite resin cores. Four teeth with a conservative prepared access cavities and without any further post preparation were used as a negative control group. After simulating the clinical situation, specimens were loaded in the Universal Testing Machine for compressive strength test. All data were statistically analyzed by the T-test.The mean compressive strengths for group 1 was 535.8 ± 155.23 N and 645.93 ± 182.98N for group 2, which were statistically significant (p-value= 0.047).Root canals filled with Resilon were significantly more resistant than that of gutta-percha, following restoration with quartz fiber posts.
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Conventional implant dentistry has been limited to healed edentulous ridges with adequate bone. Predictable success rates resulted in using dental implants in compromised situations such as insertion into old infected sites or near to pathological areas. There is significant data about marginal bone loss and lack of osseointegration around the neck of implants. However, the data about peri apical implant bone loss is really rare.An electronic search was carried in PubMed regarding articles in the time period from 1980 to 2011. Subsequent manual search was performed included all animal and human case series and clinical trials. Reported success rates and treatment options were calculated in a systematic manner.There is conflicted data showing a relatively accepted success of implantation immediately after removal of infection directly or indirectly in contact with the apical portion of the implants. However, some complications may happen that must be managed.The available data about the periapical implant pathologies is relatively inadequate. However, concluded data represents some clinical comments in order to reduce the complexities.
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Tooth impaction rarely occurs in primary dentition. Most of the primary teeth impactions are seen in second molars. The purpose of this article is to present a 4-year-old girl with bilateral impaction of inverted primary maxillary central incisors which trauma had displaced their tooth germ before erupting.
