Journal of Dentistry, Shiraz University of Medical Sciences
Volume:5 Issue: 1, 2005

Pain is one of the most commonly experienced symptoms in medicine and, as such, is a major concern to the physician. The word pain has been used by almost every one and has been described by a variety of terms and according to personal past experiences and memories of it. Pain is not only considered as a specific sensation associated with actual or potential tissue damage but also depends on cultural background, cognitive, motivational and affective factors, personality, attention and so on. Being so, with the full knowledge that any definition for pain is arbitrary and open to question, one may define pain with its multidimensional nature as an unpleasant sensation created by a noxious stimulus which acts as a protective mechanism. Pain not only includes a sensory discriminative component but also involves the accompanying reaction elicited by the stimulus. So, the study, diagnosis, and treatment of pain requires the recognition of all those factors related to the pain experience. Accordingly, familiarity with stimulation and measurement techniques and theories of pain and their related mechanisms, will be a necessity to apply pain control procedures. The purpose of this article is a relatively comprehensive review in pain continuum and its specifications based on biologic principles with the emphasis on relationship of pain mechanisms with oro-facial areas.

Statement of Problem: Dental caries and abscess, pain, trauma, oral habits, malocclusions and eruption anomalies are the main reasons for people dental visits. Other reasons are calculus dental, discoloration, anomalies in number and shape, cleft lip and palate, gingival problems, primary and secondary herpes and dental hypoplasia. The aim of this study was to investigate the reasons for visiting a dentist during the past 10 years and also to evaluate the tendency of parents for treatment of children's dental problems. In this descriptive study, 450 files from a private pedodontic dental clinic were randomly chosen. Age and the reason for visiting the dentist, and also the tendency of parents for continuing dental treatments were surveyed to evaluate the parental interest for children's dental care. The files were divided into 3 age-groups of 0-2, 2-6 and 6-12 years. The mean age of the patients was 6.4 years. The reasons for visiting the dentist were respectively dental caries (47%), pain (28.86%), clinical examination (15%), dental abscess (9.33%), tooth eruption (7.77%), trauma (6.66%), gingival problems (2%) and oral habits (1.33%). Also 18.88% of children referred for dental treatment. The most important cause of visiting the dentist was caries (47%) that shows their parents were not familiar with preventive measures. Also only 18.8% of parents brought their children for dental treatment showing most of the parents did not believe in the importance of primary dentition.

Statement of Problem: Regarding the cariostatic effect of fluoride on caries reduction and with respect to successful experiments of school-based fluoride mouth rinse (FMR) programs in some countries, Oral Health Bureau of the Ministry of Health and Medical Education decided to start FMR program in all primary school after a national survey on oral health status in 1998. The aim of the present study was to evaluate the effectiveness of this program in caries reduction of 9-year-old students after 2-3 years of using NaF mouth rinse in Shiraz primary schools. For this purpose, 200 students (100 boys and 100 girls) who were selected by simple random sampling were examined according to WHO criteria. The mean DMFT/dmft were determined and compared with the available data of 9-year-old students before starting of the program (1998). Results showed that there were not statistically significant differences in mean DMFTs of the two surveys. Similarly, the differences in mean dmfts of the two studies were not statistically significant and the reduction rate was less than the anticipated amount by Oral Health Bureau. It seems that uncontrolled use of FMR with weak supervision may be the main cause of not-significant effects of the program.

Statement of Problem: One of the difficulties that a dentist encounter during root canal treatment is the cleaning and shaping of curved root canals. While doing this procedure the probability of zipping, perforation, apical transportation and canal curvature change increases that all of those are the result of not following the original root canal path by the file. This will fail the prognosis of root canal treatment. This in vitro study was undertaken to evaluate the effects of a hand and a rotary instrumentation technique (passive step back and profile system) on canal curvature of mesial roots of human extracted molar teeth. In this experimental study, 40 mesial roots of first molar teeth with (20-40 degree) curvature were used. The roots were divided randomly into two groups of 20 and the canals were prepared by a hand instrumentation technique (passive step-back) and a rotary (profile system). Pre and post instrumentation radiographs were taken by radiographic platform. The amounts of alteration in canal curvature were measured by the aid of Adobe Photoshop 7 and Auto CAD 2000 software. Results were analyzed using Man-Whitney test. After instrumentation, canal curvature showed 85% reduction in passive-step back and 65% in profile system experimental groups. Mean canal curvature reduction in passive-step back was 3.15+1.94 while in profile system was 1.85+1.67. There was statistically significant difference between two experimental groups (p<0.05). Under the condition of this study, it seems that better maintenance of the original canal curvature in profile systems was due to the difference, between the properties of Niti and Stainless steel files.

Statement of Problem: Nowadays in all developed countries, attention to health and prevention of disease occurrence has priority to treatment. High fluoride intake through drinking water is one of the important factors of dental flourosis. This study investigates the prevalence of dental fluorosis and its relationship with level of fluoride in drinking water among children aged 12-15 years old throughout a community in Southern Iran. The study was a cross-sectional and cluster random sampling method. 406 guidances school 406 students (186 females and 220 males aged 12-15 years) in Bastak and its suburb, belonging to the city of Bandar Lenge in Hormozgan Province during 1380 were entered our study. ANOVA and t. test were used for statistical analysis by SPSS software. The study showed that high levels of water fluoride amount was the cause of prevalence and severity of dental fluorosis in the area. For instance, the rate of water fluoride in Harang village (1.55 PPM) compared to Jonahs village (0.75 PPM) showed a higher prevalence of dental fluorosis in Harang. The community flourosis index (CFI) was 0.83 which was 0.96 and 0.02 in anterior maxilla of boys and girls respectively and in posterior maxilla were 0.81 and 0.89 respectively. In anterior mandible, these figures were 0.77 and 0.84 and in posterior mandible were 0.65 and 0.71. Considering the average level of fluoride in water (1.05 PPM) and the average of local temperature (26.1ºC) with CFI of the (0.83), we can conclude that the rate of fluoride in drinking water of this area was above the WHO recommendation. Finally, we suggest that the level of fluoride should be reduced in local drinking water.

Statement of Problem: Dental caries is the most common chronic infectious diseases involving about 95% of population and still is a major cause of loss of teeth. Dental caries diagnosis is a challenging task for dental practitioners. In spite of developing different diagnostic methods for better evaluation of dental caries, conventional intraoral films continues to be the most widely used radiographic modality for the diagnosis of dental caries. The aim of this study was to evaluate the efficiency of Ekta speed plus, insight radiographic films, and RVG ui 100 in detecting proximal caries lesions. Seventy two surfaces of 36 extracted human premolars were evaluated. Radiographs of teeth blocks were taken with two different films and RVG, under standard conditions. The presence or absence of approximal caries was evaluated by six observers according to 3 points confidence scale. The actual status of each surface of the tooth was histologicaly determined from the teeth sections. Sensitivity and specificity of the imaging modalities were calculated and the observer responses were assessed with Fissure Exact Test. The sensitivity values of Ekta speed plus, Insight and RVG were 24.3%, 18% and 46% respectively, while the specificity values were 86.4%, 87.1% and 78% respectively. The difference in detecting approximal carious lesions between the systems was not statistically significant. This study suggests that there is no significant difference between the three imagining modalities in detecting approximal caries. So, Insight film and RVG ui sensor merit considerations as the new standard of care.

Statement of Problem: Bacteria and their destructive byproducts are the main causes of pulpal and periapical diseases. The main goal of the root canal therapy is to eliminate these bacteria from the root canal systems to prepare a suitable environment for the healing of periradicular tissues. Total elimination of these bacteria from root canal system is impossible, even by cleaning, shaping and irrigating with antibacterial solutions; therefore, utilization of antibacterial filling materials can help to achieve a better result. The purpose of this study was an in vitro comparison of antibacterial effect of AH26 and AHplus sealers on infected root canals with enterococcus faecalis bacteria. For this experimental study, 90 single rooted human teeth including upper incisors and canine were chosen. The crowns were removed and the root canals were cleaned and shaped. Smear layer was removed from canals and the roots were contaminated with entrococcuous faecalis bacteria following their sterilization. The roots were randomly divided into four experimental groups. The root canals of two groups were obturated using gutta percha and AH26 sealer with the lateral condensation technique. Root canals of the remaining groups were obturated by the same method but by using AHplus sealer. After incubation periods of 2 and 7 days, 4 mm segments were prepared from the middle third of roots and following removal of gutta percha from the segments, dentinal shavings were collected from the inside walls of the segments. The dentinal shavings were cultured and the presence of bacteria and the number of colonies were evaluated. The data were compared with each other by Mann-Withney and Chi-Square tests. The findings of this study demonstrated that AH26 sealer can kill all the bacteria in 2 and 7 days but AHplus sealer can not eliminate the bacteria from the infected root canals and a significant rise in the number of colonies was seen when comparing the incubation period of 2 days with 7 days. The findings of this survey illustrated a strong antibacterial effect of AH26 in comparing with AHplus which may be due to the greater amount of formaldehyde releases from this sealer.

Statement of Problem: The major objectives of root canal treatment are removal of all irritant from the root canal space and accomplish a proper shaping of the space and total obturaion of this space. So, diagnosis of root curvature is critical and can affect on proper preparation and prevention of procedural accidents. The aim of this study was to measure and evaluate the root curvature of permanent teeth that were treated at Endodontic Department of Shiraz Dental School (2001-2002). In this case control study, all endodontic treated patients with standardized radiographic films to determine the working length were analyzed and the angel of root curvature, were evaluated by Schneider method. After image projection and drawing of two lines, one on long axis of the canal and the other from apical foramen to the first line, the constructed angel was measured. From 398 evaluated films, the root curvatures in posterior teeth were more than that in anterior teeth. Most of the roots (80%) had root curvatures directed to the mesial or distal plane although root curvatures to distal plane were more common. All of the roots had mild to moderate curvatures (0-25 degrees) except the mesial root of the first mandibular molar that had severe root curvature (more than 25 degrees). The mean of root curvature of permanent teeth were between 2.76 to 28.28 degrees. The results indicated that root curvatures in teeth were common and practitioners should be aware in the case of any difficulty, and refer the case to a specialist.

Statement of Problem: Ceramic materials with excellent biocompatibility are widely used to achieve highly esthetic ceramic restorations. Although these ceramic materials usually provide an excellent restorations but failures do occur, and it is a challenge to the dentist. A number of composite resin systems are marketed for repair of failed porcelain restorations. Repair of failed porcelain restorations typically involves adhesion of a composite resin to the fractured porcelain. The porcelain surface can by physically altered with air abrasion, a diamond bur, or hydrofluoric acid (HF). Silanization of porcelain and viscosity of bonding agent is an important factor in this respect. The goal of this study is to compare three commercially available composite resin materials and one type of porcelain, in relation to their bond strength under a flexural load with an instron testing machine. Fifty porcelain blocks of 8×5×3 mm were divided into 3 groups of 15 experimental blocks (repaired with 3 different composites) and 5 blocks as control group and their bond strength were evaluated under a flexural load with an instron testing machine. The result revealed that flexural bond strength as follows: XR-Bond/Herculite (group 1)>Scotchbond Multi-Purpose/Brilliant (group 2)>Syntac Single-Component/Tetric Flow (group 3). Bond strength in group 1 was significantly different from groups 2 and 3, however differences between group 2 and 3 was not significant. Physical and mechanical Properties of composite resin are important factors on flexural bond strength. Highly-filled composite produces higher bond strength. In addition to the size of filler particles, range of the particle size, is very important. In evaluating the bond strength, stresses of polymerization shrinkage and voids are very important too. XR-Bond/Herculit system has also the ability to mature the bonds. This ability may be responsible for the higher bond strength. It seems that XR Bond/Heraclites is a proper composite for repair of this type of ceramic.

Statement of Problem: The most prevalent congenital disorder related to palate and lip is clefting. In these patients, the prevalence of dental and skeletal anomalies is more than normal individuals affecting both permanent and milk teeth and is different in different populations due to racial differences. This study was performed to determine the prevalence of dental abnormalities in patients with cleft lip and/or palate. In this cross sectional study, dental casts, lateral cephalograms, panoramic (O.P.G) and periapical (P.A) radiographs and photographs of 51 patients with cleft lip and/or palate were obtained to determine the prevalence of dental anomalies. The collected data were analyzed by SPSS software and the normal and cleft side were compared using Binominal and t-tests. The cleft occurrence was more frequent in males (56.9%) than females (45.1%) while unilateral cleft was more on the left side (47.1%) than the right side (33.4%). The most dental anomaly was tooth missing (70.6%). The upper lateral incisor in the cleft side was more susceptible to dental missing abnormalities. The incidence of dental abnormalities was greater in the cleft side than the noncleft side. Comparing the results of this study to other similar studies, it seems that cleft lip and/or palate patients show similar pattern on the prevalence of the various dental anomalies excluding racial differences.

Statement of Problem: Intraoral radiographs are the most common diagnostic tool used to assess alveolar bone loss with periodontal origin. However, radiographic assessment tends to underestimate the amount of bone loss. Digital processing and manipulation of radiographic images may enhance diagnostic interpretation of radiographs.

The aim of the present study was to evaluate the validity of linear measurement of intraosseous periodontal lesions by conventional periapical (PA) and digitized radiographs in comparison with clinical measurements.

In this practical study, 35 standard conventional PA radiographs (Parallel technique) were obtained from 50 vertical periodontal osseous lesions. During mucoperiosteal full thickness flap surgery, the distances between the depth of periodontal osseous lesions and the crest of interproxiaml bones were measured and compared with liner measurements of the lesions by conventional PA radiographs and digitized radiographs manipulated by gamma adjustment Photoshop 7.0 software for statistical evaluation. The results of the two radiographic measurements were compared with intrasurgical measurement by Dunnett test.

Conventional PA radiographs underestimated the depth of lesion in comparison with clinical measurements. Linear measurements by the two observers did not show any significant difference between digitized radiographs and clinical dimensions, but measurements by the third observer underestimated the depth of the lesion in digitized radiographs in comparison with clinical measurements. However, the amount of underestimation was less than that of measured by conventional PA radiographs.

In this study, the validity of digitized radiographs was more than that of the conventional PA radiographs in comparison with clinical measurements (Gold standard).

Statement of Problem: Head and neck cancers represent approximately 2-5% of neoplasms which is more in some countries. For example, 50% of cancers in India are of oral cavity and pharyngeal origin. Head and neck cancers are more prevalent in men, but in some regions of oral cavity, this ratio may be reversed. The majority of patients diagnosed with Head and neck cancers were over the age of 40 years. This study was undertaken to determine the number of persons with head and neck cancer who were admitted in Radiotherapy Department of Nemazee Hospital during 2003-2004. In this retrospective study from 2003 to 2004, 496 subjects with head and neck cancers referred to Radiotherapy Department of Nemazee Hospital were evaluated. All patients were categorized according to sex, age, dose of irradiation and localization of the tumor. The mean age of patients was 49 for men and 43 years for women. The most common site of the head and neck cancers was the brain (228 cases, 46%), followed by neck (57 cases, 11.5%) and larynx (56 cases, 11.3%). Squamous cell carcinoma (SCC) was the most common tumor followed by astrocytoma, meningioma and lymphoma. It was shown that, comparison with other results, there were some similarities as well as differences in some instances. This research revealed that approximately 13.5% of patients who were admitted in Radiotherapy Department of Nemazee Hospital suffered from head and neck cancers. Due to complications of radiotherapy specially osteoradionecrosis, proper dental management plans before and after treatment seems necessary.

Statement of Problem: High consumption of sugar-containing beverages is common among children as well as adults. Its adverse affects on dental structure have been widely recognised, such beverages contribute to development of caries through decrement in dental plaque pH. The porpuse of this study was to evaluate the changes of dental plaque pH following consumption of sugar–containing beverages according to DMFT value. In this in vivo filed trial experimental study, 60 volunteers (12 years old) were divided into 2 groups, one group including 30 subjects with DMFT>5, and another group including 30 subjects with DMDT=0. Dental plaque pH measurements were carried out previous to and following consumption of sugar-containing beverages. For DMFT>5 group, dental plaque pH measurements previous and subsequent to beverage consumption were 6.21 0.06 and 5.56 0.06 respectively, while for DMFT=0 group, these measurements were 6.66 0.06 and 6.34 0.07. Therefore, dental plaque pH value of DMFT>5 group in each condition was lower than that of DMFT=0 group in the comparable condition. In DMFT>5 group, dental plaque pH value subsequent to beverage consumption reduced by 0.65 0.07 and in DMFT=0 group, this reduction was 0.23 0.06. It could be concluded that the subjects with DMFT>5 were more suseptible to dental caries than the subjects with DMFT=0. The difference is explainable by more extensive reduction of dental plaque pH and closely approaching to critical pH (5.5), detected in DMFT>5 group. Therefore, it is recommended that parents should carefully control oral hygiene and limit the sugar–rich diets of their childrens with higher DMFT value. In addition, dental community including dentists could help to prevent caries by means of conferring knowledge about unfavorable results of high consumption of low–pH sugar containing beverages and diest too.

Statement of Problem: Otitis Media (OM) is one of the most common diseases in young children which is regarded as a debilitating and costly important disease. The purpose of this study was to assess some of the possible risk factors that might be related to the occurrence of OM in the first two years of life. The study was carried out on 200 children, with the age of 2 years or younger. Parents were asked to complete a questionnaire on the occurrence of OM, Pacifier use, thumb sucking, blanket sucking, feeding habits and also about parental smoking, parental educational level and occurrence and duration of day care attendance. Pearson Chi Square test was used for statistical analysis. More than 75% of children were reported to have experienced one or more episodes of OM during their first two years of life. It was found that pacifier use, feeding habits, blanket sucking, day care attendance, parental smoking and parental educational level were significantly associated with the occurrence of OM. OM was a common disease during the first two years of life and significant association existed between OM and different sucking habits, day care attendance, parental smoking and parental education. In this regard, parent's information and attention on the possible risk factors can significantly reduce the risk of OM occurrence.

Statement of Problem: The prevalence of Cl. III malocclusion has been reported to be various among different races (3-5%). Early treatment of this malocclusion is highly recommended. This study was performed to determine the effect of chin cap in early treatment of Cl. III malocclusion on the nasomaxillary complex and mandible. In a cases control study, 40 Cl. III patients treated by upper jaw appliance and chin cap, on the basis of reverse overjet and/or concave profile, were chosen. The mean force was measured to be 200 gr on each side for 18 hours/day. The mean age was 8.5±2 years old while 55% were female and 45% were male. The analysis of cephalometric data before and after treatment were done considering the skeletal, dental and soft tissue variables. The mean treatment period was 22+12 months and was continued until 34 months. Cephalometric measurements showed the following changes: SNA=0.5±1.313, Co-Po.A=2.7±2.348, SNB=-1.7±1.555, GoGnSN=1.7±1.605, NPog-FH=1.1±2.466, LAFH=2.8± 2.772, Wit’s=2.7±1.872, ANB=1.1±1.331, IMPA=-3.1±4.298, 1 to NA=3.1±5.078 demonstrating an increase in anteroposteiror indices of maxilla, vertical change of mandibular growth and a change in the angle of anterior teeth of upper and lower jaws. Changes in upper and lower pharyneal space were not statistically significant. There was a negative correlation between the effect of chin cap therapy and age which was appeared in the early stages of its application.

Statement of Problem: Despite numerous cephalometric studies and criteria proposed with respect to standards for hard tissue, studying and analysis of soft tissue has received much less attention in Iran. This study aimed to evaluate adults facial soft tissue with normal occlusion and skeletal relationships in Fars province. In this study 1500 university students in the age range of 18-24 years were examined clinically. From whom, those with normal occlusion and balanced faces were selected for cephalometric evaluation. After analysis, 44 subjects including 23 females and 21 males with normal cephalometric measurements were selected to conduct Steiner, Rickett’s, Merrifield and Holdaway analysis on their facial soft tissue. The obtained values were then compared with standard ones using the above Cephalometric soft tissue analysis and the T and Leven’s statistical tests. According to the results of Merrifield analysis, values for the Z angle were almost identical and did not display a significant variation within each of the female and male groups. Using the Rickett’s analysis, the mean distance for upper and lower lips from the E-line were not radically different, and similar values were obtained for both groups. The male subjects had more distinctive projected lips compared to their female counterpart. According to the results obtained from Steiner analysis, the mean distance value for the male group was higher than that of the female group. However the results from Holdaway analysis showed that only three variables out of a total of 11, chin thickness, upper lip thickness and the extent of upper lip strain had a statistically significant difference between the two subject groups. The remaining measured variables did not display any significant differences. We can conclude that men suffered from a higher upper lip strain compared with women. Furthermore, with the exception of Steiner and Holdaway (only for three of the measurements), statistically no significant differences were observed between the values of the sampled subjects and those sampled outside Iran.