Journal of Dental Medicine

The goal of this review was to determine the prevalence of cysts in the oral and maxillofacial regions, specially odontogenic cysts, as determined by age, sex and location.This research reviewed 6826 biopsies from department of oral pathology school of dentistry at the medical sciences university of Tehran from 1360-1376 (1981-1997).The results obtained revealed that 19.48% of biopsy lesions were cysts of osseous structures, of which 81.9% were odontogenic cysts, 12.4% psuedocyst and 5.7% were Non- odontogenic in origin.The most common lesions of the oral cavity were odontogenic cysts of which the subgroup of radicular cysts (which belong to the category of inflammatory odontogenic cysts) consisted of 49.15% radicular cysts occurred with the higher incidence in males in their third decade of life and were found most commonly associated with the upper jaw.Dentigerous cysts fall in the second most common group at 25.71% of odontogenic cysts.These cysts had a male predilection with a peak incidence in the second decade and were most common in the lower jaw.In the third group were the keratinized odontogenic cysts at 19.25%. These cysts had a male predilection with a peak incidence in the third decade and the lower jaws were twice as likely to be involved as the upper jaw. Other types of odontogenic cysts were noted to be less common in occurrence.In this study it was discovered that mcoceles consisted of 63.5% of pseudocysts and were found most commonly in the lower lip, with surgical ciliated cysts at 33.7% were the most common Non- odontogenic cysts and were found exclusively in the upper jaw adjacent to the maxillary sinus.Over all it can be stated that about y5 of all oral and maxillofacial lesions were cysts.The most common cysts were odontogenic cysts which due to their higher prevalence and various types, most be carefully examined at the histopathological level to diagnose and therefore administer definitive treatment.

Background and Aim: An important purpose of adhesive dentistry is restriction of cavity preparation to carious dentin removal and conservation of sound dentin. Application of caries disclosing agents and cavity disinfectants can help achieving this goal. The aim of this study was to evaluate the effect of caries disclosing agents and cavity disinfectants on microleakage of composite resin restorations.

Materials and Methods: This experimental in-vitro study was performed on class V cavities in 48 extracted human sound premolars. The teeth were randomly divided into four equal groups. In group 1 caries detector dye (Seek, Ultradent, USA) and in group 2 cavity disinfectant (Consepsis, Ultradent, USA) were applied on dentinal surfaces. In group 3 both mentioned materials were applied. Group 4 was considered as control group. PQ1 bonding agent and Amelogen composite were used to restore the cavities. Gingival microleakage was assessed by dye penetration. Data were analyzed by Kruskall Wallis and Dunn tests. P<0.05 was the level of significance.

Results: Group 2 showed the least and group 4 showed the highest microleakagehowever no statistical significant difference was found among the groups.

Conclusion: The use of caries disclosing agent (Seek) and cavity disinfectant (Consepsis Liquid) did not adversely affect the sealing ability of dentin bonding resins.

Background and Aim: In treatment of posterior crossbite awareness of the effects of Haas and Hyrax rapid maxillary expanders (RME) on nasal cavity will help the clinician to select the better appliance. This study was carried out to compare the effects of Haas and Hyrax expanders on the nasal cavity of patients treated for posterior crossbite.

Materials and Methods: A clinical trial study was designed on posteroanterior (PA) cephalograms of 30 subjects to evaluate the nasal cavity width of 14 subjects (8 female & 6 male) with mean chronological age of 12± 2years who received RME with Hyrax type and 16 subjects (9 female & 7 male) with mean chronological age of 11±1.6 years who received Haas type palatal expander. Paired t-test was used to analyze the outcomes of expansion in each group. Student t-test was used to compare Haas and Hyrax groups.

Results: The mean value of screw expansion was 9±2 mm in both groups. In Hyrax group nasal cavity width
(Nc-cN) increased from 29.2 ±1.94 mm to 31.7 ±1.93mm (p= 0.001) and In Haas group it was increased from 27.75± 2.21 mm to 29.35 ± 2.26 mm(p= 0.043). When two groups were compared to each other, statistically this increase was more significant in Hyrax than in the Haas group (p=0.038).

Conclusion: In this study RME affected geometry of the nasal cavity by increasing the nasal cavity width. However In our sample, Hyrax appliance demonstrated better performance over the Haas appliance in all variables.

Background and Aims: Considering advantages and disadvantages of mineral trioxide aggregate (MTA), Calcium Enriched Mixture (CEM) cement has been developed recently. The purpose of this study was to compare the apical microleakage of the root-end cavities prepared by ultrasonic or Er,Cr:YSGG laser and filled with MTA or CEM cement.

Materials and Methods: Eighty single-rooted, extracted human teeth were instrumented and obturated. Root-end resection was made by removing 3 mm of the apex. The teeth were randomly divided into two experimental (n=30) and two positive and negative control (n=10) groups. After that, the retrograde cavities were prepared using ultrasonic or Er,Cr: YSGG Laser. According to the root-end filling materials (MTA or CEM cement), each group was then divided into two subgroups. Finally, specimens were cleared for assessing the amount of apical dye (Indian ink) penetration. The data were analyzed using Kruskall-Wallis and Dunn tests.

Results: Laser/CEM cement group showed significantly the lowest mean apical dye penetration. There were no statistically significant differences between Laser/MTA, ultrasonic/MTA and ultrasonic/CEM cement groups.

Conclusion: Based on the findings of this study, CEM cement demonstrated lower rate of apical leakage compared with MTA, when the root-end cavities prepared with Er,Cr:YSGG Laser. The sealing ability of MTA was not different following root-end preparation by ultrasonic or Er,Cr:YSGG Laser.

  Background and Aims: Iatrogenic damage to adjacent tooth during proximal cavity preparation is one of the most common side effects in operative dentistry. The aim of this study was to determine prevalence of iatrogenic damages to adjacent tooth during the preparation of proximal Class II cavities among undergraduate students at dental faculty of Tehran University of Medical Sciences in 2010 .

  Materials and Methods: 106 posterior permanent teeth which had Class II decay with sound proximal surfaces of adjacent teeth were selected and restored by dental students awarding the aims of the present study. After finishing restoration, proximal surfaces were completely dried by air and evaluated with dental chair light. In doubtful cases, surfaces were evaluated with × 3 magnification. Damages were classified into 2 groups abrasion and groove. Data were analyzed using Fishers exact and Pearson chi square tests .

  Results: The frequency of adjacent surfaces damage were 57.5%, with 31.1% damages as abrasion and 26.4% as groove. Students who used matrix band and wedge in proximal area as preventive instruments showed 53.4% damages and other students showed 57.3% damages (P>0.05). A significantly higher number of females and students at restorative course level (3) used wedge and matrix band than males and students at restorative course level (4) for protecting adjacent teeth (P<0.05).

  Conclusion: According to the high percentage of iatrogenic damages on adjacent sound teeth in class II cavity preparation, teaching of preventive methods and using proper techniques is necessary for dental students as future dentists.

  Background and Aims: Microleakage is an important problem with direct restorations and familiarity with contributing factors is of utmost importance. The aim of this study was to evaluate the microleakage of three glass ionomer restorations in class V cavities.

  Materials and Methods: In this in vitro study, class V cavity preparations were made on the buccal and lingual/ palatal surfaces of 30 human premolars (60 cavities). The specimens were divided into three group (n=10, 20 cavities). Restored as follows: group1: with Fuji IX (HVGI) ionomer/G coat plus, group 2: Ionofil molar (HVGI)/ G coat plus, and group 3: Fuji II LC (RMGI) / G coat plus. All specimens were finished and polished immediately and were thermocycled (2000 cycles, 5-50°C) . In each group half of the teeth were load cycled (50000 cycles). Finally, the teeth were immersed in 0.15% basic fushine dye for 24 hours at room temperature and then sectioned and observed under stereomicroscope. Data were analyzed using Kruskal-Wallis, Man- Whitney test and a comparison between incisal and gingival microleakage was made using Wilcoxon analysis.

  Results: It was shown that the mechanical load cycling and filling material did not cause a statistically significant increase in the incisal and gingival microleakage in any of groups (P>0.05).

  Conclusion: It was concluded that the extent microleakage of Fuji II LC was similar to that of the highly viscous glass ionomers (Ionofil molar, Fuji IX) and load cycling did not increase the microleakage.