Journal of Dental School
Year:2001 | Volume:19 | Issue:2|Papers Count:16

The purpose of this study was to compare the effect of three different techniques of root canal preparation on the quantity of apically extruded debris. Extrusion of debris during or after the canal preparation may cause problem in endodontic therapies.A total of 45 Human mandibular canine and premolar teeth were selected with single canal and matured apex and divided into three groups.Step - back technique, was used to prepare the root canals in the first group, while passive step – back technique was employed in the second group, and the balanced force technique in the third group.The final limit of canal preparation for three groups was apical foramen and files used were corm Flex-R type. Extruded debris was collected into the pre weighted vials from apical foramen during root canal preparation. The mean weight of debris in each group was compared and tested using one way analysis of variance and multiple Duncan tests.Results indicated that although all the three techniques had apically extruded debris, more statistically significant extrusion of debris was observed in the group treated by means of step-back technique. There was no statistically significant difference between passive step-back and balanced force techniques for their amount of extruded debris.Factors such as canal length, canal curvature, and the size of apical foramen werE found to have no effect on the quantity of apically extruded debris.

The role of pharyngeal space has been debated on developing respiratory problems and craniofacial deformities for many years. The purpose of this investigation was to find any differences in oropharyngeal dimensions between skeletal class I and class If malocclusions.Eighty patients with class I malocclusion (40 in 9-13 year & 40 in 18-30 year-old age groups) were compared to sixty patients with class Il malocclusion due to mandibular deficiency (30 in 9-13 year & 30 in 18-30 year old age groups). Patients were selected from those who had no respiratory problems, facial asymmetry, aberrant growth pattern, parafunctional habits, TMJ diseases, vestibule-cochlear, visual & hearing disorders, hypertrophy of adenoids or tonsiles, previous orthodontic treatment or maxillofacial surgery.A lateral cephalogram in Natural Head Position was taken from every patient. Skeletal relationships of craniofacial structures and oropharyngeal dimensions were measured together with the soft palate. Hyoid bone and cervical column position Results indicated that:1- There was no difference in oropharyngeal dimensions, soft palate, hyoid hone and cervical vertehral column position between skeletal class I and class If malocclusions in the normal respiratory pattern.2- Oropharynx showed some degree of growth in vrtical dimension during the growth period whereas  its sagittal depth remained mostly stable, except in the upper and lower border al class I malocclusion (PNS-UPW: p<0.01, Spt-PSpt: P<0.03, Va-PVa: P<0.01).The hyoid bone showed down ward move while the posture of cervical column and facial growth had no change. Finally, Soft palate showed a significant increase in length (PNS-U: P<U.OI) at class I malocclusion.

Gingival recession has been advocated and believed to have a multifaclorial etiology and therefore is, t considered as difficult to manage. This study was designed to detect-the effect of poor oral hygiene and/ or mechanical trauma from faulty brushing on gingival recession.A total of 320 patients with gingival recession were selected for this study. Miller's classification of gingival recession was used to measure the level of recession in each case In addition. CI-S, DI-S and OHI-S indices were also evaluated for each' individual.Results showed that 42% of patients, had gingival rescission due to wrong brushing technique while, 37% had gingival recession associated with poor oral hygiene.Male patients developed a slightly higher incidence of gingival recession compare to female ones. The number of cases with class I recession observed was significantly higher, particularly in the upper jaw. Trauma caused by wrong brushing was seen more frequently in canine and premolar areas. In conclusion: Poor hygiene and traumatic brushing were found to play important roles in gingival recession overall.

The effect of intermaxillary fixation was evaluated on pulmonary function of 35 patients with no history of smoking or respiratory problem. Patients were selected from those receiving treatment in oral and maxillofacial department at Taleghani General Hospital from Qct. 1998 to Apr. 1999. A spirometer was used to measure the breathing volume, both before and after the surgical procedure.Results showed a decrease in FEV1, FVC, FEF (75%) and PEF indices to %8.12, %19.24 and %24, respectively. In conclusion: As results of this study indicated. Serious attention is needed to protect airway of patients who had received intermediary fixation especially for those with upper jaw treatment.

This study was conducted on 588 pupils in the city of Doroud (280 girls and 308 boys) during the Academic year 1999-2000.This cross sectional study was performed on a population, selected in a stratified random sampling manner. Data was collected using a questionnaire, in addition to a clinical examination of each case. The age of pupils was between 11 to 15 years.Results showed a DMF score of 4 in boys and 3.23 in girls. Over all 62.5% of boys and 37.5% of girls reported to have used toothbrush for their Oral hygiene maintenance. In total, 56%, of pupils had visited the dental clinics only for extractions from which 55.6% had gingivitis.In Conclusion: Overall girls had a higher oral hygiene quality compare to boys of the same age.

The aim of this study was to determine the effect of parental awareness an the oral hygine status of 7 years old children, in 1996. A total of 540 pupils were selected from twenty primary schools of five educational districts throughout Tehran.In addition to an oral examination, a questionnaire was distributed among parents of these children. The incidence of caries was measured by dmft index and their oral hygine by DIS index. The level of parental awareness of different fields were evaluated in duding the cause of caries, the importance of fluoride on prevention of caries and the impact of early missing of primary teeth. Over all, 468 returned questionnaires were used for data analysis.Results implied that most of the parents believe the underuse of tooth brush and dental Doss as being the major factor for caries promotion. While Duo ride is scientifically introduced as the best preventive measure. There is a coherent relation between the parental level of education and their awareness on the impact of different items on tooth dacay. The mean score of dmft was shown to be greatly depend on mother's educational level.

Locating mental foramen is highly important for any safe surgical procedure in dentistry. This is because of the situated mental nerve within the mental foramen. This study, has evaluated the location of mental for a men in association to the lower premolar teeth as a landmark in mandible of a group of Iranian patients. A total of 182 radiographs (panoramic x ray views) were taken for assessment in 91 men and 91 women, aged 12 to 60 years. Result showed that the most common location of mental foramen is between 4 and 5, both in men and women (82.4% women 82.4% women). In vertical plane, mental foramen was found to be located slightly lower than the midpoint of the distance between the lower border of mandible and the alveolar margin. The location of foramen in horizontal plane, was found to be at approximately 1/3 level of the distance from the symphysis menti to the angle of mandible.

The purpose of this study was to measure the level of fluoride uptake in sound enamel following application of two commercially available local dentifrices. One of the samples contained sodium fluoride (Naf, Crend-Iran) while the other contained sodium monofluorophosphate (SMFP, Naseem-Iran). The control ones were namely Crest (Procter & Gamble-USA) and Macleans (Smith line-Beech man-UK).A total of fourty intact freshly extracted first premolar teeth were used for this study which were divided into 4 groups, for test and control. Each tooth was first sectioned into two equal parts each of which were then covered with nail varnish leaving an area of 6mm free in diameter. Solutions were prepared from centrifuging tooth pastes with deionized water which were later applied to the exprimental samples. This was then followed by Acid etch enamel biopsy 1echnique. The technique was used for two different depths on experimental and control groups by perchloric acid (0.5 mole). Fluoride concentration of each biopsy solution determined at each depth of enamel in biopsy steps using atomic absorption spectrophotometry technique.Results showed the level of fluoride uptake to be in a higher level for Crend and Nassem compare to the original Crest and Madeans tooth pastes in the first layer (P< 0.05). But this value was the same for Naf products and still slightly higher in SMFP Iranian product at the second layer (P<0.05).In conclusion, fluoride uptake level from Iranian tooth pastes tested were similar or even superior to the similar international brands.

The purpose of this study was to compare the bond strength of etched bridge retainers to enamel, following the application of different surface treatments and adhesives.Sixty sound human extracted canines teeth were selected for this study. Cobalt Chromiun - bryllium retainers were made to adjust to the lingual surfaces of each tooth.Specimens were divided into three groups for their surface treatme!1t including: Sandblasting, Chemical etching and Heat treatment. Each group Was then divided into three subgroups based on the use of each luting cemented: SBMP *, Dpo Cement ** of Enforce***.After treating the surface of both retainers and enamels, samples were bonded to the enamel surface of lingual side of the teeth. The shear bond-strength of the specimens were measured at a blade crosshead with the speed of 2mm/min after one week storage in 100% humidity at 37°C.The ANOVA and Duncan test were employed for any possible diference between groups.Results indicated that:1-The type of luting cement is not important after Air abrasion and Heat treatment.2- Using chemical treatment, the bond strength of SBMP and Duo cement shows a greater rise compare to Enforce (106.7kg).3- Bond strength of Enforce was found to be similar for all surface treatment methods.4- SBMP with Duo Cement, showed the greatest bond strength when chemical treatment was employed in comparison to the other treatment methods.5- The greatest bond strength was seen in SC group.6- There was an acceptable enamel bond strength associated with heat treatment.In Conclusion: Chemical treatment and SBMP is found to have the best result compare to the heat treatment and air abrasion technique.

The purpose of this invitro study was to investigate the effect of disinfectants on die dimensional changes of condensation silicones. A mandible dent form was used associated with a stainless steel model for veneer crown. This model was prepared by C.N.C apparatus and inserted in the socket of the tooth No. 5 and Cemented with Duo cement.Two types of condensation silicone namely Rapid and Speedex were employed for this investigation. Fifteen impressions were taken from, each group. Only 10 out of 15 impressions were disinfected using 2% Acid glutaraldehyde and 0.5 -1% sodium hypochlorite, While the other 5 impressions served as no disinfected in each group for Control. Impressions were then rinsed under the cold water and stored in room temperature for 30 minutes. Study moles were made for control groups using type IV gypsum. Impressions in experimental group were immersed in disinfectants for 30 minutes. Dimensional measurements were performed using a two dimensional measuring method.Statistical analysis of the data was done using ANONA and Duncan tests,. Results indicated that: 1- There was no significant difference in dimensional changes between experimental and control groups. 2- Dimensional changes were found to be less than Zero. However occlusogingival length was found to be longer in Rapid impression (0.51%) compare to Speedexone (0.18%).

The term Calcifying Odontogenic Cyst was first used by Gorlin in 1962 to describe a new cystic entity with a peculiar pathogenesis and histologic feature. With time it became apparent that not all Calcifying Odontogenic Cysts were really cystic. Some, in fact, appeared as a solid neoplasm, the epithelial lining of a Calcifying Odontogenic Cyst appears to have the ability to induce the formation of dental hard tissues in the adjacent connective tissue wall. Other Odontogenic tumors such as the amcloblastoma, and odonto-amelohlastoma may sometimes he associated with the lesion. This article presents a case of COC which has given rise to AOT.

Different reconstructive methods have been reported in the literature including the application of barrier membrane, graft materials and root conditioning agents to treat alveolar vertical bony defects. As there is, still unclear message to how could definitely dealt with the problem this study was designed to evaluate the clinical effect of locally applied doxycycline with hydroxyapatite and palatal connective tissue as a barrier in the treatment of interproximal vertical bony defects.Ten patients were selected with average age of 39.5±2.79 years, seven female and three male, who had at least one pair of bilateral interproximal vertical bony defects. Each patient was considered to present one tooth in one site as test and another one in the other site as control. Local doxycycline, hydroxyapatite and connective tissue were used in test group while hydroxyapatite and connective tissue were employed in the control site. Variables including: pocket depth, gingivial margin location, clinical attachment level, alveolar bone defects depth and location of alveolar crest were measured in baseline and six months later at Re-entry procedure using an acrylic stent as a reference point.Results indicated a statistically significant difference between before and after treatment steps for each variable (pocket depth, gingivial margin location, clinical attachment level, alveolar bone defects depth and location of alveolar crest). A statistical.ly significant difference was found between two groups except in the probing depth value. Defect resolution was found to be greater in test compare to control group (65.87% versus 55.5%).In conclusion: Application of hydroxyapatite, doxycycline and connective tissue together is more effective than individual usage for the treatment of alveolar vertical defects.

There are different terms in use for different typs of medical study designs and trials.Translating these terms in to Farsi, needs special care avoiding misinterpretations This article asks medical investigators attention to focus on the real features of different concepts.The main study designs such as surveys, case-control, cohort and interventional trials are discussed briefly. At the end suggestions are made in choosing the right analysis for each design appropriately. Their major strengths and weaknesses are also mentioned.

Diagnosis of the true patient's problems desires and needs, can result in the selection of the best esthetic treatment planning. This was based on the dentist respect to the individuality of members of the population and recognition of their normal range of variation in commune structural esthetic aspects. All changes in the appearance of the teeth including: form, color, size. arrangement and teeth relationship are recommended to be in harmony in any esthetic treatment planning with the three principal factors: 1-Health and hygiene preservation, 2-Function and 3-Stability. This paper reviews different aspects of the problems and shares the values of proper diagnosis and it's importance in an accurate and desirable result.

Periodonlal diseases are considered as one of the most prevalent problems among oral diseases. Conflicting hypothesis have been presented on the role of crowding on periodontal diseases and plaque accumulation. This study was. Therefore designed to evaluate the prevalence of periodontal diseases associated , with crowding. A total of 360 patients, age ranged 15-19 years were evaluated in Tehran province in a randomized multi-stage sampling manner. Those cases whose the distance between right and left cupids was smaller than the sum of the sizes of four anterior incisors were considered as "Cases", while "Controls" were those with no such crowding. Periodonlal status of the cases was evaluated using bleeding on gentle probing, calculus. And pockets depth measurement in the teeth 46, 31, 36, 26, 11, 16. Plaque accumulation was also compared in both groups using Ramfjord Index without considering proximal surfaces in the teeth 45, 44, 37, 36, 25, 24. 21. 17, 16.Results showed no relationship between the crowding and periodontal disease whereas pockets with the depth of more than 3.5 mm were found in anterior teeth in about 11.2% of the case group and 3.8% of the control group. Anterior teeth absence of plaque accumulation was seen in 15.5% control and 5.4% of the case group.