Frontiers in Dentistry
Volume:10 Issue: 5, Sep 2013

One of the most important goals of orthodontic treatment is to create an esthetic, well balanced facial profile. However, the components of a well-balanced Iranian facial profile have not yet been established. The purpose of this study was to evaluate the anteroposterior lip position of the Iranian population and to compare the perception of orthodontists, dental students and orthodontic patients using a series of silhouettes with varying anteroposterior lip positions. Average female and male silhouette profiles were constructed from the profiles of 30 Iranian men and women with a normal skeletal relationship. The lips in each average profile were protruded or retruded in 2-mm increments and the 7 images were arranged randomly. Thirty orthodontists, 30 dental students and 30 orthodontic patients were asked to score each silhouette from 1 (very bad) to 5 (very good). Both the orthodontists and the students preferred the average profile for men and slightly more retruded lip position for women. Orthodontic patients had a wide range of preference for men and selected more retruded lip positions for women. The least-favored profile was the most protrusive in the 3 groups. These findings suggest that Iranian orthodontists, dental students and orthodontic patients prefer an average profile for men and slightly retruded profiles for women.

Failure of soft liners depends mostly on separation from the denture base resin; therefore measurement of the bond strength is very important. The purpose of this study was to compare the tensile bond strength of two soft liners (Acropars, Molloplast-B) to denture base resin before and after thermocycling. Twenty specimens from each of the two different soft liners were processed according to the manufacturer’s instructions between two polymethyl methacrylate (PMMA) sheets. Ten specimens in each group were maintained in 37°C water for 24 hours and 10 were thermocycled (5000 cycles) among baths of 5° and 55°C. The tensile bond strength was measured using a universal testing machine at a crosshead speed of 5 mm/min. Mode of failure was determined with SEM (magnification ×30). Two-way ANOVA was used to analyze the data. The mean and standard deviation of tensile bond strength of Acropars and Molloplast-B before thermocycling were 6.59±1.85 and 1.51±0.22 MPa, respectively and 5.89±1.52 and 1.37±0.18 MPa, respectively after thermocycling. There was no significant difference before and after thermocycling. Mode of failure in Acropars and Molloplast-B were adhesive and cohesive, respectivley. The bond strength of Acropars was significantly higher than Molloplast-B (P<0.05).

This study compared diet and regular Coca-Cola on enamel erosion in cold and room temperatures. Seventy five enamel specimens were prepared and divided into 5 equal groups (N=15) as follows: Group 1: regular beverage at room temperature, Group 2: regular beverage at refri-gerator temperature, Group 3: diet beverage at room and Group 4: diet beverage at refrige-rator temperature. The specimens were immersed in the regular or diet beverage (Coca-Cola, trade mark regd. Khoshgovar Co., Tehran, Iran) at room (20°C) or refrigerator (2°C) temperatures for 20 minutes, 3 times per day for 7 days. Specimens in the control subjects (group 5) were placed in synthetic saliva at room temperature for 7 days. The hardness of specimens was tested using Vickers test under 500 gr loads for 5 seconds. The data were analyzed using two-way ANOVA and Tukey tests. The mean and standard deviations of micro-hardness values of the studied groups were as follow: G1: 304.26±29.71, G2: 285.53±42.14, G3: 279.06±39.52, G4: 266.80±23.98 and G5: 319± 30.79. There was a significant difference in the beverage type as the main factor (p<0.05), but temperature factor and their interaction effect on enamel hardness showed no significant difference (p>0.05). Tukey tests showed that there were significant differences between control and diet groups as well as regular and diet groups. Diet Coca-Cola is more erosive than the regular type and the temperature of the beverages used had no significant influence on enamel erosion.

Tooth fracture is a common dental problem. By extension of cavity dimensions, the remaining tooth structure weakens and occlusal forces may cause tooth fracture. The aim of this study was to evaluate and compare the fracture resistance of teeth restored with direct and indirect composite restorations. Sixty-five sound maxillary premolar teeth were chosen and randomly divided into five groups each comprising thirteen. Fifty-two teeth received mesio-occluso-distal (MOD) cavities with 4.5mm bucco-lingual width, 4mm pulpal depth and 3mm gingival depth and were divided into the following four groups. G-1: restored with direct composite (Z-250, 3M/ESPE) with cusp coverage, G-2: restored with direct composite (Z-250) without cusp coverage, G-3: restored with direct composite (Gradia, GC-international) with cusp coverage, G-4: restored with indirect composite (Gradia, GC-International) with cusp coverage. Intact teeth were used in G-5 as control. The teeth were subjected to a compressive axial loading using a 4 mm diameter rod in a universal testing machine with 1 mm/min speed. Data were analyzed using one-way ANOVA and Tukey tests. The mean fracture strength recorded was: G-1: 1148.46N±262, G-2: 791.54N±235, G-3: 880.00N±123, G-4: 800.00N±187, G-5: 1051.54N±345. ANOVA revealed significant differences between groups (p<0.05). Tukey test showed significant difference between group 1 and the other groups. There was no significant difference among other groups. Direct composite (Z-250) with cusp coverage is a desirable treatment for weakened teeth. Treatment with Z-250 without cusp coverage, direct and indirect Gradia with cusp coverage restored the strength of the teeth to the level of intact teeth.

The bond strength of adhesives in irrigated dentin behaves differently over time. The aim of this study was to evaluate the influence of long-term water storage and thermocycling on the microtensile bond strength of adhesive systems to dentin irrigated with endodontic solutions. Sixty human molars were used after removal of the occlusal portion and exposure of the dentin by grinding. The specimens were irrigated with 2.5% NaOCl for 30 minutes and then 17% EDTA for 5 minutes and assigned to six groups according to the adhesive system (n=10): G1 and G2–Clearfil SE Bond; G3 and G4–Single Bond 2; and G5 and G6–XP Bond. The teeth were restored with composite and were subjected to water storage for different time periods. G1, G3 and G5 were stored for 24 h; G2, G4 and G6 were stored for 6 months and were subjected to thermocycling (12,000 cycles, 5°C to 55°C, 500 cycles per week for 6 months). After storage, the tooth/restoration assembly was sectioned to obtain four sticks of approximately 1 mm2, for microtensile bond strength testing. The results were analyzed by two-way ANOVA and Tukey’s test. Significant differences were observed among the adhesives (p<0.01). No significant differences were observed in the microtensile bond strength between samples after 24 hours of storage without thermocycling and after 6-month storage with 12,000 cycles (p<0.05). The bond strengths of G5 and G6 after irrigation with 2.5% NaOCl and 17% EDTA were significantly different from those of other groups. Long-term water storage/thermocycling had no effect on bond strength to dentin.

Accurately localizing the mental foramen and mandibular canal is important when administering local anesthesia and performing surgery; therefore, knowing the normal range of the possible locations is essential. Our purpose was to assess the location of the mental foramen and mandibular canal in an Iranian population using panoramic radiography. Standard panoramic radiographies were performed. The positions of 100 mental foramens were evaluated. The distances from the center of the mental foramen to the superior and inferior borders of the mandible and to the apexes of the first and second premolar were measured. The distance of the mental foramens from the mandibular midline and the diameter of the mandibular canal in the mental foramen connection were also measured. Among 100 mental foramens, 6% were positioned under the first premolar, 24% were between the first and second premolars, 67% were under the second premolar, and the remaining 3% were behind the second premolar. The mean distance from the mental foramen to the mandibular midline was 27.77±3.20 mm. The mean diameter of the mandibular canal in the mental foramen connection was 3.09±0.69mm. The mental foramen was near the second premolar and the inferior border of the mandible. This information can be used to perform safer mental nerve blocks in surgical interventions.

Different studies have reported contradictory results about the effect of osteoporosis on periodontal status. We performed this study to evaluate the periodontal status of menopausal women by methods with enough accuracy and confidence. This study was performed based on the evaluation of bone mineral density using dual energy X-ray absorptiometry in 2010. A total of 60 patients who met the inclusion criteria were selected and divided into three groups of osteoporosis, osteopenia, and normal. Then, evaluation of periodontal markers such as pocket depth (DP), attachment loss (AL), and tooth loss (TL) was performed by a dental student. A panoramic radiography was performed for those who were suspicious of periodontal disease and bone decline. Finally, evaluation of the periodontal indexes was compared among the three groups using ANOVA with 95% confidence interval. Mean bone decline was higher in the osteoporosis group compared to the other two groups, but the difference was not significant (P=0.065). In addition, mean of plaque index (P=0.123), pocket depth (P=0.856), attachment loss (p=0.525), and tooth loss (p=0.884), the number of people with attachment loss ≥ 2millimeter (P=0.866) and the number of people with alveolar bone loss ≥ 2 millimeter (P=0.348) were not significantly different between the three groups. In this study, no significant difference was observed between the three groups in terms of plaque index, pocket depth, attachment loss, or tooth loss. However, further studies are required that could control all the possible confounding variables.

The focus of this paper is to evaluate the influence of mechanical characteristics of the implant on primary stability in different bone types, based on resonance frequency analysis (RFA). A number of 60 Nobel Biocare Replace Select TiUnit Tapered implants of two different lengths (10 mm and 13 mm) and three different widths as 3.4 mm (narrow platform (NP)), 4.3 mm (regular platform (RP)) and 5 mm (wide platform (WP)) were placed into two different groups of bone blocks. Bone blocks were different in bone quality, but similar to bone types D1 and D3. Immediately, after implant placement, implant stability quotient (ISQ) was measured using the Osstell mentor device. ISQ values for implant placements in D1 bone were significantly higher than those for implants placed in D3 bone. In D1 bone, the implant length did not make any significant difference in primary stability; however, in D3 bone, the primary stability of the implant increased when longer implants were utilized. NP implants presented significantly lower ISQ values compared to the two wider implants. In cases of low bone quality, the optimum increase in the implant length and diameter should be taken into account to achieve higher primary stability.

To report the association of pulp calcification with that of cardiovascular disease (CVD) using digital panoramic dental radiographs. Digital panoramic radiographs of patients referred from the angiography department were included if the patient was under 55 years old and had non-restored or minimally restored molars and canines. An oral and maxillofacial radiologist evaluated the images for pulpal calcifications in the selected teeth. The sensitivity, specificity, positive predictive value and negative predictive value of panoramic radiography in predicting CVD were calculated. Out of 122 patients who met the criteria, 68.2% of the patients with CVD had pulp chamber calcifications. Pulp calcification in panoramic radiography had a sensitivity of 68.9% to predict CVD. This study demonstrates that patients with CVD show an increased incidence of pulp calcification compared with healthy patients. The findings suggest that pulp calcification on panoramic radiography may have possibilities for use in CVD screening.

The purpose of this study was to evaluate the shear bond strength (SBS) of orthodontic brackets bonded with two types of nano-composites in comparison to a conventional orthodontic composite. Sixty extracted human first premolars were randomly divided into 3 groups each containing 20 teeth. In group I, a conventional orthodontic composite (Transbond XT) was used to bond the brackets, while two nano-composites (Filtek TM Supreme XT and AELITE Aesthetic Enamel) were used in groups II and III respectively. The teeth were stored in distilled water at 37°C for 24 hours, thermocycled in distilled water and debonded with a universal testing machine at a crosshead speed of 1 mm/min. The adhesive remnant index (ARI) was also evaluated using a stereomicroscope. AELITE Aesthetic Enamel nano-composite revealed a SBS value of 8.44±2.09 MPa, which was higher than Transbond XT (6.91± 2.13) and Filtek TM Supreme XT (6.04± 2.01). Statistical analysis revealed a significant difference between groups II and III (P < 0.05). No significant difference was found between groups I and III, and between groups I and II (P > 0.05). Evaluation of ARI showed that Transbond XT left fewer adhesive remains on teeth after debonding. Results of this study indicate that the aforementioned nano-composites can be successfully used for bonding orthodontic brackets.

The primary aim of this study is to determine maximum bite force in molar and incisor regions of healthy individuals, to evaluate the bite force after open reduction and internal fixation of mandibular fractures using micro plates, for a period of up to 6 weeks and to determine the rate of recovery of maximum bite force in an Indian population.

Plagiocephaly (oblique skull) is premature fusion of one of the coronal sutures. Frontal plagiocephaly is a rare congenital deformity in the skull that is the most complicated form of craniosynostosis to treat. Examination of all sutures is necessary for diagnosis of craniosynostosisIn this article, a 10-month-old, healthy girl with deformity of the right forehead and orbit that is caused by frontal plagiocephaly and coronal unilateral synostosis is presented.This abnormality was corrected by frontal craniotomy and fronto-orbital complex advancement under general anesthesia.An exact clinical and radiographic (Multislice CT scan with 3- dimensional three dimensional reconstruction) examination with the suitable time of surgery is necessary for diagnosis of skull abnormality and prevention of treatment delay. Furthermore, 3D stereo-photo-grammetry is a radiation-free, non invasive method for evaluating the growth pattern of children in long term.