Journal of Mashhad Dental School
Year:2003 | Volume:27 | Issue:1-2|Papers Count:13

Introduction: Today, in modern dental practice, .one of the main reasons for orthodontics and orthographic surgery, in addition to improvement in morphology and function, is prevention of periodontal problems. The purpose of this study was to evaluate. the effects of interdental astronomies on periodontal tissues.Materials and Methods: In this prospective Cohort study, 18 patients with class II Malocclusions were selected and for them, interdental astronomies was done. Using periodontal probes and periapical radiographies, the patients preoperative periodontal conditions at the site of astronomy were evaluated as well as postoperative conditions (1,3,6 and 12 months).Results: 1) 6 pathological periodontal lesions were found in 40 segmental astronomy sites.2) Among 6 pathological periodontal lesions, 4 areas were with osseous periodontal defects and 2 areas with missing teeth.3) The prevalence of periodontal defects after segmental surgery in men was two times more than women.Conclusion: A low incidence of dental loss and periodontal defects occurs in the region of segmental astronomies.

Introduction : The purpose of this study was to determine the prevalence of open bite in 11-14 year old boy students in Ahwaz in 2001 .Materials and Methods: This study was a descriptive cross sectional investigation with cluster sampling on 744 students (11-14 year old boys).Results: The total prevalence of open bite was 14.5%. 7.8% exhibited only anterior open bite, 6/1 % posterior open bite and 0/4% showed both anterior and posterior open bite.Conclusion: Open bite has relatively high prevalence in Ahwaz early diagnosis and treatment can inhibit many future complications.

Introduction: Among several cephalometric analyses used in orthodontics. Done of them could present all diagnostic and interpretative features. The aim of this study is to apply a simple and convenient approach which could enable the orthodontists to gain maximum information from it.Materials and Methods: Cephalograms of 58 adults patient (40 femals and 18males) with mean age of 15 years and 4 months, were used for analysis. After tracing, the relationship between mandibular plane and the most inferior point of posterior cranial fosse was assessed.Results: The data revealed that:- SNA and SNB were less than norms which was not significant. - In patients with normal facial height, extension of mandibular plane lay lower to posterior cranial fosse and the mean distance was 6.84 mm. - Mp-Ar-NAngle was 42°to 55°(49 ± 6) that was 2° less than Norms.Conclusion: Extension of mandibular plane to posterior cranial fosse or lower, shows that there is a failure in vertical growth.

Introduction: It is impossible to prepare and obturate the root canal correctly without basic information about the root canal anatomy.The purpose of this study was to evaluate the root canals of mandibular first premolar by the-staining the canals and cross sectioning the roots by stereomicroscope.Materials & Methods: In this study 100 extracted intact first premolar were selected and the root were sectioned at CEJ point by metal disc. After removing the pulpal tissue, the teeth were cleaned completely from pulpal stumps and necrotizing tissue using the 30.% H2O2 for 48 hours. After washing and drying the teeth, all surfaces of roots except one millimeter around the apical foramen were covered with nail polish. Then they were centrifuzed with Eosin 5% for 20 minutes after that the teeth were washed and the nail polish was cleaned by acetone. Finally the teeth were sectioned horizontally to 1-1.5mm sections by hand piece and metal disc.The sections of apical to coronal were studied by stereomicroscope and the number of canals, the type of canals, the shape of canals in apical, middle root and coronal area, adjoining site of the canals and separation site of the canals and apical foramen position was evaluated.Results: 57% of teeth had one canal, 37% had 2 canals, 5% of, teeth had 3 canals and 1% had 4 canals. 57% of teeth were type 1,6% type II, 29% type IV and 8%of teeth were classified as miscellaneous group. Adjoining site of canals in type II were 88%, apical and 16.7%pf teeth were in middle part. Separation site of the canals in type IV were 6~5% apical and 34.5% in middle part. The cross sections of canals in coronal root were 6.8%, ellipsoid 27%, striped 3% round and 2% figure 8.The cross sections of canals in middle root were round in 74%,. ellipsoid in 21%, striped in 4% and C. shaped in 1%. Cross sections of canals in apical part were round in 99% and striped in 1%.Conclusion: According to the above findings, it maybe concluded that considering the variety of canal configurations, mandibular first premolar could be easy or difficult to treat witch is in accordance with other studies.

Introduction: Failure to obtain adequate anesthesia in teeth with inflamed pulp has always been a major clinical problem for the dentists generally specially endodontists. Capsaicin and zostrix depletes substance p blocks axonal transport and apparently inactivates small A delta and c-type fibers. Morphine which is an efficient analgesic drug, blocks never conduction and shows its anesthetic and analgesic property via voltage dependent sodium channels. The purpose of this clinical study was comparison of the effect of local application of capsaicin, zostrix and Morphine on complete anesthesia of teeth with inflamed pulp and poor response to traditianl local anesthetics.Materials & Methods: In this study sixty patients with pain during access preparation despite successful local anesthesia were selected. All patients had received one to three injections of lidocaine 2% with 1.80000 epinephrine. Capsaicin, zostrix or morphine was applied in the cavity on the dentin or exposed pulp for 5-10 minutes and severity of pain due to access preparation or intrapulpal injection was recorded. The data were gathered and statistically analyzed by wilcoxon and kruskal-wallis tests. Results: The best results were obtained following application of zostrix over the exposed pulp. In 88.2% of these patients application of zostrix made the pain free or tolerable interapulpal injection possible(P<0.05).Conclusion: with regard to the results obtained, the use of dehydrating and decalcifying materials such as alcohol and phosphoric acid prior to topical application of drugs on complete pulp anesthesia, is recommended

Introduction: traumatic dental injuries have a relatively high prevalence particularly in athletics. The goal of this study is to determine the prevalence of traumatized dental injuries in male martial athletes in mashhad.Materials and methods: In this cross-sectional study, 338 male athletes from twelve sports clubs, (karate, Boxing, Tac kwon do, Kungfu) of Mashhad in 2001 were examined. Each athlete was asked to fill in a questionnaire. The Craig- Hargrove's classification system was used for recording the type of dental fractures.Results: The prevalence of ,traumatic dental injuries in the studied society was 22.8%. The highest rate of dental injuries was related to boxing (34.7%) and karate (22%). Dental injuries were more common in athletes at the age of 16-20 years old (42.8%). The traumatized injuries to teeth were more prevalent in the maxilla and especially central incisors (61.2%). Enamel was injured more than the other parts of the teeth. The use of mouth guard was 15.4%prevalent, which was the most in boxing (34%).Of course the use was irregular. There was a significant difference between the use of mouth guard and prevention of dental injuries (p<0.0001). Conclusion: The most common cause of dental injuries in martial athletes was lack of the use of mouth guard. Teaching the correct use of mouth guard, and wide distribution of type n mouth guard amongst the athletes, is recommended.

Introduction: In spite of progress in dental material science, considering strength and bonding, PFM restorations still have 5% failure after 10 years. The main aim of this investigation was to choose a system with better bonding, more strength and esthetics, simpler technique and more durability.Materials & Methods: In this invivo investigation, twenty upper premolars were selected. The crowns were made in the usual manner and then a layer of porcelain was removed using stone from buccal cusp. In half of the samples both metal and porcelain were exposed and in the other half metal was not exposed. The crowns were cemented with Temp-Bond and then the fractured area was repaired intraorally with Vivadent system. The patients were recalled after 2 weeks, 1, 3,6 and 9 months to check durability and success rate of the restoration. Finally the data were analyzed statistically.Results: We calculated the success rate of restoration to be 80% in porcelain-exposed group, 100% in porcelain-metal-exposed group and 90% totally.Conclusion: Intraoral porcelain repair, with the use of Vivadent system can be used instead of removing and remaking fractured crowns with satisfactory durability in long terms.

Introduction: Dental porcelain is one of the best materials ever used in dentistry. Excellent tissue compatibility, esthetics, very low solubility in oral fluids, high compressive strength, and the lowest bacterial plaque accumulation on the glazed porcelain are some of its advantages.Porcelain brittleness due to its low tensile strength and impact strength, and occlusal attrition of opposing tooth enamel are some of its disadvantages.Different ways have been proposed to eliminate the brittleness of porcelain and strengthen it, of which baking porcelain on a metal framework is more commonly used. Restoration and replacement of the teeth by porcelain fused to metal restorations is still the most commonly used approach, so we tried to produce porcelain dentin powder.Materials & Methods: To test the bond strength between opaque Ti14and Dentin D4, and compare it with vita porcelain, 30 porcelain disks with 4mm thickness were made (2mmopaque and 2mm Dentin). 10 samples of Vita opaque and Vita Dentin and 10 samples of opaque Ti14 and Dentin D4 and 10 samples of vita opaque and Dentin D4 were tested using an impact test machine. Results: Samples were observed under light and scanning electronic microscope for the quality of bond.There was no significant difference between Dentin D4, opaque Ti14 and Dentin- Vita, opaque- Vita. The quality of bond was also identical and no micro crack was observed according to microscopic examination.Conclusion: The bond strength between opaque Ti14 and Dentin D4 .with opaque-Vita and Dentin- Vita is not significant difference from aspect quantity and quality.

Introduction: This invitro study evaluated the effect of ultrasonic cleanser after casting surface treatment on bond strength of alloy to enamel. Therefore, the aim of this study was to evaluate the effect of ultrasonic on bond strength of etched base metal.Materials and Methods: 80 sound canines were selected. After cleaning and mounting in cold cured acryl, rectangular Ni-Cr-Br plates with 9 mm2 surface area and 0.5 mm thickness were made (hat adapted with lingual surfaces. One process was created in mid part of each plate.Fitting surface of all samples were sandblasted. They were divided into two groups of 40,based on the type of treatment: A)surface treatment with acidic M3 gel. B) surface treatment with 150-200µ alumina sandblast. Finally each group was divided into two subgroups of 20, based on using the ultrasonic or without using it. Then samples were adhered to lingual surfaces with Scotch Bond Mulit Purpose (3M - Co). and Duo Cement (Coltene). After 1000 thermal cycling, shear test was established by cross head speed of 2mm/min. Data analysis was done by two variables ANOVA with 95% significance level.Results: 1. Mean bond strength was significantly greater in subgroup without ultrasonic use (60-74 kg) than the other subgroups (45- 62kg).2. The group using just M3 acidic gel without ultrasonic had the greatest bond strength (74.52 kg).3. Comparing two factors (Sandblast- Acid), bond strength was greater after using acid.4. Increase in bond strength was observed in all groups without ultrasonic use. Conclusion: Use of M3 acidic gel without ultrasonic use increases the bond strength of Ni-Cr-Br alloy to enamel significantly.

Introduction: The aim of this study was to evaluate periodontal destruction among patients with types I & II diabetes mellitus compared with non-diabetic patients.Materials and Methods: Periodontal destruction was assessed in the following 3 groups: 1) 24 type I diabetic subjects (IDDM, aged>12 yrs.), 2) 24 type II diabetic subjects (NIDDM, aged>40 yrs.), and 3) 10 non diabetic patients of any age range. Clinical parameters included probing pocket depth, plaque index, Russle's Index as well as radiographic bone loss.Results & conclusion: Statistical analysis of findings demonstrated that variation in periodontal indices among the 3 groups was mainly due to variation in the age of subjects. Type I diabetic subjects had a greater score for Russle's Index as compared to the other 2 groups even after adjustment for age. Diabetes duration was in positive correlation with the degree of periodontal destruction regardless of the diabetes type.Furthermore, fasting blood glucose level had a positive but insignificant correlation with various periodontal indices.

Introduction: New bone productions, a frequent feature in many bone diseases, may originate from normal bone forming elements (trabeculae, and periosteum) or from tumor cells. Although estrogenic and chondrogenic tumors alone are able to produce new bone, some neoplasm's infections, trauma and some other diseases can initiate react ional ontogenesis. It is of paramount importance to distinguish one from the other.The purposive this study was recognition of different types of preinstall reactions which are helpful in differential diagnosis radio logically. Here is a report of a rare case of buccal cyst with preinstall reaction.Results: The CT scan technique, panoramic and periapical radiography didn't show the preinstall reaction in this buccal cyst and preinstall activity with onion-skin pattern was well apparent in cross-sectional occlusal technique.conclusion: Regarding the overview of different preinstall reactions, it can be concluded that the recognition of different radiographic patterns and choosing the proper radiographic technique accompanied with clinical finding, helps us in final diagnosis of bony lesions.

Introduction: Herpes Simplex Virus infection (HSV) is one the most frequent causes of oral Lesions .Therefore a one year follow up study was carried out on patients attending to the Oral Medicine Dept. of Mashhad dental school, and Dermatology Dept. of Mashhad Ghaem Hospital. report of 4 patients was also done to determine the or facial features of HSV infection.Materials & Methods: We filled out a questionnaire for each of the patients who had Acute Primary and Recurrent Herpes simplex infection to get information about the frequency of different types of HSV infection, routes of transmission, demographic distribution, site of lesions, constitutional symptoms, predisposing factors, the course of recovery of the lesions and the potential role of the polio vaccine on HSV infection. (From March 1997 to March 1998)Results: Our one year study revealed that primary and recurrent HSV infection occurs in all ages and has the same classic clinical features. Conclusion: This study indicates that orofacial HSV infection could be diagnosed by its clinical view and is treated easily. Another study about the efficacy of polio vaccine on H.S.V. is recommended."