مجله دندانپزشکی دانشگاه علوم پزشکی تهران
سال هجدهم شماره 3 (پیاپی 44، پاییز 1384)

Oral health care workers may be exposed to a variety of infectious agents as they carry out their professional responsibilities. Dentists must recognize diseases that are most commonly transmitted in dental offices. Oral health care providers should assess their needs for immunization based on the characteristics of their clinical work setting and own risk-taking profile. Relevant articles in the medical literature were derived from searching Medline database (1966 to present) with key terms immunization, oral health care and dentist. On searching the database, a total of 70 studies were included in this review. Use of vaccines safeguards the health of workers in various type of oral health care delivery settings.

Today several materials have been used for root- end filling in endodontic surgery. Optimal properties of Pro Root MTA in in-vitro and in-vivo studies has been proven. On the other hand, based on some studies, Root MTA (Iranian Pro Root MTA) and Portland cement are similar to Pro Root MTA in physical and biologic properties. The aim of this study was to evaluate bacterial leakage (amount and mean leakage time) of four root- end filling materials. In this experimental in-vitro study, seventy six extracted single- rooted human teeth were randomly divided into six groups for root-end filling with gray Pro Root MTA, white Pro Root MTA, Root MTA (Iranian Pro Root MTA), Portland Cement (type I) and positive and negative control groups. Root canals were instrumented using the step- back technique. Root- end filling materials were placed in 3mm ultra sonic retro preparations. Samples and microleakage model system were sterilized in autoclave. The apical 3-4 mm of the roots were immersed in phenol red with 3% lactose broth culture medium. The coronal access of each specimen was inoculated every 24h with a suspension of Streptococcus sanguis (ATCC 10556). Culture media were observed every 24h for colour change indicating bacterial contamination for 60 days. Statistical analysis was performed using log- rank test with P<0.05 as the limit of significance. At the end of study 50%, 56.25%, 56.25% and 50% of specimens filled with Gray Pro Root MTA, White Pro Root MTA. Root MTA and Portland Cement (type I) had evidence of leakage respectively. The mean leakage time was 37.19±6.29, 36.44±5.81, 37.69±5.97 and 34.81±6.67 days respectively. Statistical analysis of data showed no significant difference among the leakage (amount and mean leakage time) of the four tested root- end filling materials (P=0.9958). Based on the results of this study, there were no significant differences in leakage among the four tested groups at 60 days. The results suggest that Root MTA and Portland Cement can be used as less expensive root filling materials.

The treatment of epulis fissuratum is surgery, but a new proposed modality is laser surgery. The aim of this study was the comparison between laser and blade surgery in the treatment of epulis fissuratum. In this clinical trial, 12 patients with epulis fissuratum were selected. The lesions were divided into two parts. One part was resected by laser and the other by surgical blade randomly and single blinded. The time of surgery, bleeding, wound repairment as well as the depth of vestibule were measured. Data were analyzed using Wilcoxon sign test and Paired t test with P<0.05 as the limit of significance. The wound of laser surgery healed sooner and the depth of vestibule in laser side was deeper comparing with blade surgery. Also the time of surgery was less than blade. Based on the results of this study, we suggest that laser surgery is a more useful technique for the treatment of epulis fissuratum.

Preserving canal curvature during different phases of canal preparation is an important point. In Endodontic therapy all efforts are made to prepare canal in a way that final canal follows the primary canal curvature. The purpose of this study was to evaluate the efficacy of root canal preparation performed by students at Endodontic Department of Dental School, Tehran University of Medical Sciences. In this retrospective study, classic method of step- back technique was investigated for preserving canal curvature in mesial roots of first mandibular molars and mesiobuccal roots of first maxillary molars between years 2000 and 2004. A randomly selected sample of 400 dental patient records was investigated by 4 observers (Endodontic department professors), searching for procedural errors. A clear explanation sheet of curvature preservation and procedural errors such as ledge formation, apical foramen transportation, zipping and stripping and a questionnaire were prepared for observers. The observers went through reliability test and kappa value for agreement between every two observers. The results were above 0.8. Data were analyzed by EPI6 statistical computer program, using Chi-Square and Fisher exact test with P<0.05 as the limit of significance. This study consisted of 152 first maxillary molars and 248 first mandibular molars. The prevalence of curvature preservation in mesial root of first mandibular molars and mesiobuccal root of first maxillary molars were 38.5% and 47.6% respectively. Procedural errors detected consisted of 33% ledge formation, 26.1% apical foramen transportation, 1.8% zipping and 4.1% stripping for mesial root of the first mandibular molars. The results for the first maxillary molars were 27%, 19%, 3.2% and 3.2% respectively. The study results revealed the efficacy of endodontic education and the proficiency of junior and senior students in preparing curved posterior root canals. The results obtained in this retrospective study are comparable to prospective studies.

Pulpotomy is one of the routine methods for pulp therapy of primary teeth. At present it is a fact that ideal agent for this has not been discovered. The aim of this study was to compare the clinical and radiographic success rates of electrosurgical pulpotomy versus formocresol pulpotomy in human primary molar teeth. In this clinical trial study, pulpotomy was performed on 68 primary molars in children aged from 5 to 10 years. The teeth were treated using either a conventional formocresol (35 teeth), or electrosurgical technique (33 teeth). Following the pulpotomy procedure, the teeth were evaluated regarding clinical and radiographic success for 3, 6 and 9 months periods. The teeth were evaluated clinically and radiographically for the presence of pain, abscess, fistula, mobility, internal and external resorption and radiolucency. Finally clinical and radiographic data were collected and analyzed with Fisher exact test using P<0.05 as the limit of significance. After 9 months follow up, the clinical and radiographic success rates for the electrosurgery group were 96% and 84% respectively and for formocresol group, 100% and 96.8% respectively. There were no statistically significant differences between the success rates for the two groups (P>0/05). Although electrosurgical pulpotomy is a nonpharmacological and easy to use technique, further investigations with longer evaluation periods are suggested.

Along with higher usage of dental local anesthesia with risks to people health together with their positive role, the important goal of dentistry, patients’ health, has been stressed repeatedly nowadays. This study was conducted to compare O2 saturation, respiratory rate and heart rate of patients following injection of anesthetic containing vasoconstrictor (lidocaine 2%) and without vasoconstrictor (Mepivacaine). This experimental study was conducted on 32 healthy humans (16 females and 16 males) with 25-50 years age range and no history of drug usage. Cases were classified into two matched groups. O2 saturation, heart and respiratory rate were recorded before extraction of a mandibular posterior tooth. In the first group, 3.6 ml lidocaine 2% with 1:80,000 epinephrine and in the second group Mepivacaine 3% was injected, using inferior alveolar dental nerve block with aspiration. Variables were measured and recorded. Tooth extraction was performed and the mentioned variables were recorded again. Data were analyzed with SPSS software using t and Paired t-test with P<0.05 as the limit of significance. After injection of lidocaine, the heart rate was increased (12.25±1.75 bpm), and the time to reach the maximum rate was 64.75±11.26 seconds. After extraction of tooth, heart rate in both groups was increased not considering the type of injection. The study showed that the injection of lidocaine (containing epinephrine) in patients without contraindication has no risk. Also, possible increase in heart rate is not risky and is not associated with O2 saturation decrease and respiratory interruption.

A strong causal relationship exists between cigarette smoking and development of oral squamous cell carcinoma, so oral screening using exfoliative cytology has been recommended to facilitate the early diagnosis of cellular alterations in oral mucosa and silver staining (AgNOR technique) has been proven to be of value in the detection of incipient cellular alterations. The purpose of this study was to compare the argyrophilic nucleolar regions (AgNORs) count of cells collected from normal mucosa of cigarette smokers with that obtained from non- smokers. In this cross-sectional study, cytologic smears of normal tongue, buccal mucosa and floor of the mouth from 19 smokers and 19 non- smokers were stained for AgNORs. The AgNORs count was established on 100 cells. The count value of groups were compared and analyzed using the Levens, Paired T, Student and Factorial tests. Using P<0.05 as the limit of significance. The AgNORs were round and had a clustered distribution in both groups. The mean AgNORs count was statistically higher in cells of smokers than non- smokers (P<0.05). There was a significant difference between smears from the floor of the mouth and other anatomical sites in both groups. In this study, no correlation was found between AgNORs count and gender. Analysis of AgNORs suggests that there might be a correlation between the smoking habit and an increased rate of cellular proliferation in the oral mucosal cells.

It has been suggested that osteoporosis may be a predisposing factor for periodontitis and tissue destruction, thus periodontitis and mandibular bone density might be related. The purpose of the present study was to evaluate the clinical signs of periodontal tissue destruction in postmenopausal women. In this cross-sectional study, 60 postmenopausal women (51 to 78 years of age) underwent radiographic examination of the right mandibular premolar. Mandibular bone density (MBD) was measured using optical densitometry. Periodontal status variables examined included: probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP) and plaque index (PLI). Data were analyzed by statistical tests using P<0.05 as the limit of significance. This study found no statistically significant association between the four indicators of periodontal disease and mandibular bone density, but there was statistically significant association between mandibular bone density and the number of remaining teeth. There was also statistically significant association between PPD and the number of remaining teeth. These findings suggest that individuals with high MBD seem to retain teeth with deep periodontal pockets more easily than those with lower MBD.

Proper shaping and cleaning of the root canal system is one of the most important aspects of endodontic treatment. To estimate the canal length before instrumentation in endodontic treatment, traditionally, conventional radiographic techniques and recently Direct Digital Radiography (DDR) are applied. The application of computer technology to radiography has allowed less exposure time, image acquisition, manipulation, storage, retrieval, and transmission to remote sites in a digital format, elimination of wet processing and considerable reduction in the time lapse between image acquisition and display. The purpose of this study was to compare the accuracy of DDR versus conventional radiography in estimating endodontic file lengths of curved canals in first mandibular molars. In this test evaluation study, fourty extracted human first mandibular molars with root curvature were selected.Samples were divided into two groups: With root curvature less than 25 and more than 25. Samples were mounted in plaster blocks and canal lengths were estimated by using DDR and conventional radiographs. Regression analysis and correlation coefficient were used to calculate statistical differences between the groups with P<0.05 as the limit of significance. Conventional radiography was more precise in canals with less than 25 degrees curvature (P=0.160). While, DDR was more precise for canals with curvature more than 25 degrees (P=0.605). However, these differences were not statistically significant. The image quality of DDR system has improved to the point that it can now be used for estimating canal lengths, even for curved canals, with accuracy comparable to that of conventional radiography.

The goal of endodontics is to seal the root canal system from the orifice to apical constriction completely and tridimensionally.Hence perforations during root canal therapy, because of caries or resorptions must be sealed and obturated with ideal materials. The aim of this study was to histologically compare two kinds of mineral trioxide aggregate Root MTA and Pro Root MTA for furcal perforation repair in developed teeth in dog. In this experimental study, thirty teeth consisting of second, third and fourth mandibular premolars of five German shepherd dogs were selected. Twenty-four teeth were randomly divided into four experimental groups (6 teeth each). One pair of Root MTA and Pro Root MTA groups studied in one month and the other in three months intervals. Positive and negative control groups was each contained three teeth. In positive control group, perforations were not treated and negative control group contained intact teeth. In experimental groups perforations repaired after one week exposure to oral cavity with Root MTA or Pro Root MTA. After time intervals animals were subjected to vital perfusion and 6 m histologic sections were prepared. Inflammation and hard tissue formation were ranked by Cox criteria. Data were analysed using Mann-Whitney and Chi-Square statistical tests with P<0.05 as the limit of significance. There was statistically significant lower inflammation and higher hard tissue formation in three months Root MTA and Pro Root MTA groups compared to one month interval (P<0.05). There was no statistically significant difference in inflammation and hard tissue formation between Root MTA and Pro Root MTA in each intervals (P>0.05). Mineral Trioxide Aggregate is an adequate material for furcal perforation repair in dog’s teeth. Root MTA could be a good substitute for Pro Root MTA considering the lower cost and similar characteristics.

Although the need for "adequate" amount of keratinized tissue (KT) for periodontal health is questionable, the mucogingival junction (MGJ) often serves as a measurement landmark in periodontal evaluations. Limited information is available on the reproducibility of KT width (KTW) assessment. The purpose of this study was to assess reproducibility of 3 different methods to identify MGJ location. In this test evaluation study, fourteen patients contributed with 40 teeth. At the midbuccal aspect of each tooth, KTW was assessed by 2 independent examiners after MGJ identification by the visual (VM), functional (FM), and visual with histochemical staining (HM) method. Data analysis was based on intra-class correlation coefficients (ICC) and paired t test. The results of this study exhibits no significant differences in keratinized tissue width assessment in visual and histochemical methods, but a significant difference in functional method is found. Intra- and inter-examiner reproducibility has been shown to be substantially consistent when different methods of mucogingival junction determination are used to measure in order to determining corono apical dimension of the gingival. Finally the results of this study indicate that all three methods for detecting MGJ location are accurate and reproducible, but if we need more accuracy and reproducibility, the histochemical method is recommended.

With the introduction of porcelain veneers to fulfill patients’ esthetic needs, question raises about the ability of the veneers to cover the substructure discoloration. It seems that using shade modifiers under the porcelain veneers can neutralize the discoloration. The goal of this study was to determine the efficacy of shade modifiers in correcting tooth discoloration, when used with resin cements under porcelain veneers. In this experimental study, 60 porcelain discs with two thicknesses of 0.7 mm and 2 mm (30 porcelain of each thickness) were made from ceramco porcelain powder. 40 of them were in A2 shade and 20 were made by the mixture of A2 shade porcelain powder and porcelain stain to represent tooth discoloration. Then all the laminate discs (0.7 mm) were cemented over the 2 mm thick discs to make groups of 10 samples as followed: 1- The first group: laminate discs + resin cement + 2mm thick discs with A2 shade. 2- The second group: laminate discs + resin cement + 2mm thick discolored discs. 3- The third group: laminate discs+ resin cement+ shade modifier+ 2mm thick discolored discs. The color of 30 specimens was measured by spectrophotometer in 2 conditions. 1- To include the specular reflection (SCI). 2- To exclude specular reflection (SCE). In each condition the specimens were measured on both a white background (W) and a black one (B). The mean color differences (E) of each specimen in the second and third group with the specimens of the first group were calculated. Data were analyzed using Paired sample t-test and P<0.05 of significance. Color measurements showed that in SCIW condition L was significantly different among the three groups except the first and the third. In SCEW condition all the parameters showed significant differences. In SCIB condition, E was not significantly different between the second and the third groups. Hue (h) parameter wasn’t different between groups one and three neither was chroma (c) among the three groups. In SCEB condition, E was not statistically different between groups two and three. Considering the statistical results, shade modifier couldn’t completely match the color of the specimens in the third group with the first one. But, the lower E for the third group comparing to the second one means that shade modifier was successful in reducing the effect of substructure discoloration.