Journal of Dental School
Year:2004 | Volume:22 | Issue:3|Papers Count:23

Background &Aim: Enough knowledge about the anatomy of the root canal end is necessary for successful root canal therapy. Apical foramen is the point which the canal root surface towards periodontal ligament and does not necessarily conform to anatomic apex. The radiography is the most usual method for determining this point. In this study, the validity of the two methods of radiography (Parallel and Buccal object rule) in determining the apical foramen deviation from anatomic apex compared with the gold standard method.Methods & Materials: In this in vitro study 68 maxillary and mandibular molars were chosen and the cavity preparation was done by standard method. Then according to canal's diameter, files No. 10, 15, 20 were used in a way that their tips could be seen in apical foramen area in contact with root surface. The radiographies were taken by two methods: (maxillary molars by parallel and mandibular molars by BOR method with the angle of °20). The films were developed and encoded. The radiographies were observed with a magnifier of X5 in a standard condition. The deviation of the file tip from radiographic apex were determined and recorded in the information form. The teeth were studies under a stereomicroscope to observe the exit point of the file tip (buccal, lingual, mesial, distal). The condition of the file exit point in proportion to the anatomic apex was considered as gold standard method.Results: In 52 percent of the samples, the apical foramen does not conform to the anatomic apex. The results of 5 diagnostic tests were: sensitivity, specification, NPV, Efficiency. The validity was gained in great quantity for two methods of radiography which showed that both are useful in determining the deviation of apical foramen the apex. Conclusion: Despite the apical foramen does not conform to the anatomic apex, Radiography is a useful and valid method for determining the apical foramen. However, it is better to apply other methods such as: Electronic apex finder and the wet of paper point to improve the degree of accuracy.

Background & Aim: Although there are a lot of improvements about infection control in 10-15 years ago, some problems remains in dental schools and clinics. One of the controversies related to infection control is the absence of a survey from knowledge, attitude and practice of students. This study designed to evaluate the level of knowledge, Attitudes and Behavior of Dental students in Endodontics Department of Shahid Beheshti Dental School.Methods & Materials: This study is descriptive and crosses- sectional. A questionnaire was designed to survey the knowledge and attitudes. Practice was studied by observation.Results: Average score about knowledge was 19 from 34. Average score about practice was 21 from 32. Maximum score about knowledge was 24, minimum was 13. About practice Maximum score was 30 and minimum was 7.Ninety percent of students believed that it's better to do the sterilization process. After treatment 53.6% of student waste the needles.Conclusion: Finding show lack of knowledge about infection control principles, but about attitude, finding are more positive and students tend to learn more. Cause of weakness about knowledge and practice can be the absence of curriculum and standards.

Aim: The marginal seal of a restoration is one of the most important factors for clinical success. Studies have reported several advantages for dentin bonding agents in an effort to obtain strong and durable bonds between resin-based composites (RBC) and the tooth structure. This invitro study compared the microleakage via dye penetration of four new commercially available dentin bonding systems (DBS). These adhesive materials improve the quality of the bond while simplifying clinical procedures.Method & Materials: Standaridized C1 V cavities (3mmx2mmx2mm)were prepared on the buccal and lingual surfaces at the cemento-enamel junction of 20 intact extracted human premolars and restored with a microfilled RBC (Filtek A110) following application of either Single Bond (one-bottle total-etch DBS), Prompt L-Pop (one-step self-etch DBS), Clearfill SE Bond or AdheSE (two one-step self-etching DBSs). The teeth were thermocycled, coated with wax and nail varnish and immersed in 2% basic fustian for 7 days and sectioned longitudinally. The extent of dye penetration in the occlusal and gingival walls was qualitatively evaluated under tereomicroscopy (x30). The data were analyzed by the Kruskal-Wallis nonparametric and Mann-Whitney U tests.Results: No significant differences were evident between the sealing ability of self-etch DBSs and total-etch adhesive in neither occlusal nor gingival margins. There were significant difference among occlusal and gingival walls in all of the specimens (P<0.0001) and gingival walls presented more leakage than occlusal walls. Among four groups, the difference between microleakage of occlusal and gingival margins was statistically significant only in AdheSE group (P<0.03) and this DBS had a better sealing ability in occlusal than gingival margins.Conclusion: The self-etch DBSs can provide an effective alternative to conventional total-etch systems.

Background & Aim: Dental calculus has a major role in the development of periodontal disease, so this study was designed to assess the frequency of dental calculus and its precipitating factors and the correlation between them in patients referring to Department of Oral Disease, Shahid Beheshti Dental School in 2002.Methods & Materials: 100 patients without missing in lower incisors and having teeth necessary for Sillness – Loe plaque Index were selected. This descriptive - analytical (cross sectional) study was accomplished by means of interview and observation (examination and laboratory tests). After filling out a data form, the height of calculi on lingual surfaces of lower incisors were measured by using a graded periodontal probe, and the calculus score (c.s) and Sillness – Loe plaque index were calculated for each patient. Then a saliva sample was taken and sent to the laboratory to measure the concentration of calcium. All the data collected by interviewing, examination, and laboratory results were recorded in questionnaires and finally analyzed by SPSS statistical software.Results: The research showed that the frequency of dental calculus was 75%, and the mean calculus score was 30.2±22.9. The mean saliva calcium concentration was 4.96±1.43 mg/dl. Meanwhile, there was a correlation between dental calculus and saliva calcium (∑2=0.96, P<0.0001). This study revealed that 69.2% of patients with very heavy calculus were male; 57.7% of them did not have academic education; 80.7% had poor oral hygiene; and 69.2% of them had crowding in site of dental calculus. Also 38.5% of them were cigarette smokers (O.R=17.7). Conclusion: The frequency of dental calculus and calculus scores in dental patients are high. It's mandatory to determine and remove calculus contributing factors to achieve an optimum level of oral hygiene and decrease periodontal problems.

Background & Aim: Cleaning and shaping is one of the most important steps during root canal therapy. Extruded apically debris during cleaning and shaping can produce pain and exacerbation after endodontic therapy. The aim of this study was to compare the amount of the apically extruded debris in three different methods of canal preparation. Material & Method: In experimental study for comparison of apically extruded debris in step back, sonic and step back - Sonic techniques, 39 upper central incisors were used. After determining canal length and measuring file, teeth were divided 3 equal groups, with regarded measuring file and canal length that same in all of groups. Then in group I, with setp back technique, in group II with endosonic device and in group III with combination of two techniques, canals were prepared and apically extruded debris in each tooth collected and weighted.Result: Results showed that mean weight was 4.33±3.09 in group I, 2.76±1.86 in group II and 2.86±3.41 in group II. One way analysis of variance indicated no significant differences between 3 groups, however, less debris were extruded when endosonic was used.Conclusion: There was no statistically significant difference in the amount of apically extruded debris among the three different canal preparation techniques. Although, apical foramen configuration and endosonic preparation were effective on the amount of the apically extruded debris.

Background & Aim: Analgesics, antibiotics, local anesthetics and mouthwashes are among the most common medicines which are prescribed by dentists. The aim of this research is evaluation of the knowledge and practice of general dental practitioners about mentioned medicines in Kerman.Methods & Materials: This study was a descriptive, cross - sectional survey. We constructed a questionnaire that included demographic, knowledge and practice sections. The questionnaire was prepared based on valid references. After determining of validity of questionnaire its reliability was confirmed by means of a test- retest exam. The questionnaires were distributed to 66 general dental practitioners.Results: 68.2% of the study group was men and 31.8% were women. The mean age of the study group and the duration after graduation time were 37.5 and 10.6 years respectively. The results showed that the mean knowledge score of the dentists was 5.38 out of 8. The knowledge was significantly decreased with increasing of age and the duration after graduation time (r = -0.32, P< 0.05).Conclusion: According to the results of the present study, the study population has a reasonable knowledge about common medicines used in routine dental practices. However the present study shows that information should be given to the dentists about selection of analgesics and antifungal and the duration of antibiotic therapy in oral infections. In addition, the knowledge of dentists should be increased about the Citanest (a local anesthetic) and the necessity of doing skin test before injection of Penicillin.

Aim: The purpose of this study was to compare the clinical effectiveness of the mandibular infiltration versus the mandibular block for the operative and surgical treatment of primary molars.Methods & Materials: 80 children aged 6-9 years old who required bilateral identical dental treatment in mandibular primary molars were selected. Subjects received an infiltration on one side of mandible and blockon the other. Bilateral identical procedure was performed on each patients during the same appointment. These procedures included amalgam restoration, pulpotomy, extraction, stainless steel crown. Sign of discomfort included hand and body tension, eye movement indicating pain, verbal complaints and tears. Both techniques were evaluated blindly by a single rater who was not the operator.Result: T test indicated there was no significant difference between block and infiltration for any of the factors evaluated and anesthesia profundity is not as dependent upon bone density Conclusion: Mandibular infiltration can be used versus block in treating mandibular primary molars.

Aim: The purpose of this study was to determine the prevalence of oral lesions and awareness From presence of them in patients attending to Oral Medicine Center of Mashhad Dental school.Methods & Materials: The method of sampling was consecutive, with using the poisson's method and the design of the study was cross - sectional. All subjects referring to this center were examined and filled out the questionnaires for them from September to December 2000.Results: Cases were 1310, 501 male and 809 female. The manage of the cases was 28.2±14.6 years. %75.2 of subjects referring had oral lesion, and % 24/8 had normal mucosa. Most of cases were unaware of their oral lesions (% 75.1), most of these lesions were in the soft tissue (%95.8), and most of them needed to following up (%71.5). Among the total of 48 different pathologic changes diagnosed, the most common lesions were white coated tongue (%40/8), petechia (%14.2) and geographic tongue (%6.5).Conclusion: Many patients attending the center were unaware of oral lesions in their soft oral tissue which needed to follow up. This emphasizes on examination of soft oral tissue just like teeth periodically by specialists.

Background & Aim: Among different diseases of dental pulp, less attention has been paid to the immunopathogenesis of pulp polyp. So the aim of this study was to evaluate the relationship between pulp polyp formation and allergy.Methods & Materials: For this purpose, thirty - three samples including 17 pulp polyps and 16 normal pulps were gathered. After a 3-day incubation period, sandwich and competitive ELISA techniques were used to assess the presence and concentration of IgE and histamine, respectively.Results: IgE was found in 100% of pulp polyps and 50% of normal pulps, with concentrations of 0.7615±0.4858 0.1927±0.2193 Histamine was found in 100% of polyps and 12.5% of normal pulps, with concentrations of 30.8353±34.1531 and 3.125±8.732. The two groups showed statistically significant differences in terms of both the concentration and presence of IgE and histamine. There was also a significant statistical correlation between the concentration of IgE and histamine in the two groups.Conclusion: We could suggest possible role for type I hypersensitivity reaction or allergy in the pathogenesis of pulp polyp.

Background & Aim: Through selection of accurate bite registration materials, the error in the interocclusal relationship of mounted casts on the articulator, can be minimized during fabrication of fixed restorations. Thus this study was done to determine the three-dimensional accuracy of four interocclusal recording materials.Method & Material: This quasi - experimental study measured and compared the three dimensional errors of a wax, a polyether, an impression compound and an auto polymerizing acrylic resin. A dent form was mounted on a semi adjustable arcon articulator. Ten records of each material were produced and stored for 24 hours. Following a variety of modifications on the articulator, the three dimensional deviations of maxillary dentoform member due to interocclusalrecords, were measured.Results: There was significant difference between accuracy of materials tested in all dimensions.Conclusion: The least three dimensional changes were recorded by polyether. The accuracy of the remaining materials was, in descending order, compound, wax and acrylic resin.

Aim: The aim of this study was to compare the etching effect of porcelain with Hydrofluoric acid (HF) one shear bond strength using one coat bond and self cure composite.Methods & Materials: The study was conducted experimentally using observation as its technique. 40 porcelain cubes were prepared and assigned into 4 groups. Group I specimens were treated with 35% phosphoric acid.Subsequently one coat bond was applied to bond the bracket, group II specimens were made fresh with fine diamond bur, treated with a 35% phosphoric acid and one coat bond was applied to bond the bracket, group III specimens were treated with a 20% hydroflouric acid (HF) and Nomix composite bond was applied to bond the bracket, group IV specimens were treated with a 40% HF acid and the same procedure in the group III was followed. The Instron machine was used at a crosshead speed of 0.5 mm/min to test the shear bond strength.Result: The shear strength was 2.47±1.8Mpa for group I, 5.64±2.6Mpa for group II, 3.28±1.8Mpa for group III and 3.03±2.6 for group IV. The overall difference between the four groups was statistically significant (P<0.05). Conclusion: The use of fine diamond bur and 35% phosphoric acid for Etching and use of one coat bond can achieve a successful bond between either use only phosphoric acid or 20% HF acid-Etched with No mix composite and 40% HF acid etched with No mix composite.

Background & Aim: This study was conducted to evaluate a relation between mesiodistal and buccolingual size of lower incisors and crowding.Methods & Materials: We divided the study in two parts. First we measured mesiodistal and buccolingual incisor dimensions and lower incisor crowding on dental casts of two groups. Group 1 consisted of 65 adult persons (36M, 29 F) with lower incisor crowding more than 3 mm and group 2 consisted of 60 cases with well-aligned teeth. (36M, 24 F). Then the MD and BL dimensions and their ratios were compared in two groups by statistical analysis. In part II we evaluated the crowding changes of 57 persons (24 M, 33 F) during 3 years from 12-13 to 15-16 year old. Increasing in crowding was seen only in 27 persons, and other 30 cases showed no increase In crowding. The MD and BL dimensions of lower ant teeth were compared in these two groups.Results: Cases with lower incisor crowding had larger dimensions (with exception of buccolingual of 2) (P<0.05).And there was no correlation between the changes of crowing and the size of lower incisors, either mesiodistal or buccolingual (P>0.05).Conclusion: The MD dimension of lower incisors is larger in persons with crowding than persons with aligned teeth, but we can't use MD dimension to predict later lower incisor crowding.

Background &Aim: Pain control is very important in all dental procedures. Facing experience in childhood results in one's panic from dental treatments in older age. Inferior alveolar nerve block is common for primary mandibular molars. This technique involves some disadvantages, especially in pediatric dentistry. The most important items are: 1) more stress in both child patients and the dentist 2) causes negative reactions in children behavior 3) longtime anesthesia might make the child to bite his/her tongue and lips. Regarding to these problems, the researchers have looked for a reliable alternative for the above injection technique; for example, infiltration. In this research, the effectiveness of mandibular infiltration was compared with mandibular block technique in pulpotomy of mandibular second primary molar in 5-8 years old children.Methods & Materials: In a controlled randomized clinical trial done in a single blind way, thirty 5-8 years old cooperative children which required second primary molar pulpotomy in both sides were selected. Anesthetic drug was Lidocaine 2% with Epinephrine one part in one hundred thousands in both cases. Eye movement, hand and body movement, oral complaints and crying of the child (SEM scale) were observed and recorded. Fischer's exact test and McNemar analysis were used for statistical analysis.Results: SEM scale (sound, eyes, motor) was used for pain comparison between block and infiltration technique. More number of children exhibited eye movements (P value = 0.3), body movements (P value = 0.21), oral complaints (P value = 0.21) and crying (P value = 0.23) in infiltration side. But there were no significant differences between two techniques. Conclusion: Results show that infiltration can be used, it is very simple, easy and safe in order to anesthetize second mandibular primary molars. According to the results of this study the success rate for infiltration is 80%.

Background &Aim: Aggressive periodontitis is a disease characterized by rapid destruction of supporting structure of teeth in young adult. The main causative factor in periodontal disease is the bacterial plaque, however, genetic is considered one of the main predisposing factors of the disease. Efforts to find genetic markers of this disease are one of the most active fields of periodontal research. The major histocompatiblity complex genes in human have been investigated to find correlation between the presence of specific MHC genes as possible genetic marker of certain diseases. MHC investigations on aggressive periodontitis have shown inconclusive results. The aim of this study was to address the question as to whether there is a significant association between aggressive periodontitis and HLADQB1- 0201 sub group.Methods & Materials: This was a case-control study. Data collection was performed by direct examination of samples and the study population was selected among patients referring to Periodontitic Department of Mashed Dental School, as well as periodontal practices and clinics in the city of Mashed. Sampling was a convenience sampling method through witch 59 individuals including of 30 subjects with aggressive Periodontitis and 29 periodontal healthy subjects were selected and the method of examination was PCR-ssp. X2 test was used to test the presence of significant association.Results: 14 persons of cases were positive for allele 0201 and 16 persons were negative for the allele, while 10 persons of the controls were positive and 19 persons were negative for the allele.Conclusion: These findings indicate that the prevalence of HLA- DQB1 allele 0201 is greater among subjects with periodontitis as compared to periodontal healthy subject. However, this association is not statistically significant.

Background & Aim: Periodontal problem is common finding in smokers. The aim of this study was to evaluate the relationship between smoking and CPI in 35-44 years Iranian individuals.Method &Materials: Data of this study received from non - smokers past smokers and present smokers randomized.For matching this cases. The persons, who use drugs, need to refer and cure were omitted the age was divided to 35- 37 and 42-44 years old. Whit Chi - square test the data was evaluated.Results: The incidence of CPI score in 42-44 yrs. was significantly related to smoking while this relation was no significant in 35-37 yr age group. CPI was worser in past and present smokers and was related to the number of the smoking years duration. Number of cigarette per day was significantly related to CPI.Conclusion: Present smoker who have higher age and use more cigarette daily have worse periodontal status.

Aim: Since morphologic features of different races and ethnic groups are different, knowledge of the normal dentofacial patterns of each ethnic group is important, therefore the purpose of this study was to develop cephalometric standards for the Iranian boys and girls (12 and 17 years old) and compare them to a sample of American Caucasian adolescents.Method and Materials: The subjects in this study included 65 females and 63 males. All subjects were Iranian with class I canine and molar relationship and none had undergone orthodontic therapy, all of them had cephalograms in centric occlusion and analyzed according to the cephalometric analysis of McNamara, Wits and Rakosi. Comparison between the dentofacial parameters of two groups performed using student's t - test.Results: Significant differences between Iranian and Caucasian were present in male and female groups in both ages.Conclusion: Comparison between the Iranian and Caucasian indicated that Iranian 12 years old boys have a tendency toward maxillary protrusion, vertical growth tendency and a procumbent lower incisors as compared with Caucasian boys. The same results were found for 12 years old girls. Iranian 17 years old boys and girls showed a retrognathic maxilla and mandible and more vertical growth when compared with the Caucasians standards. In male 17 years old group there were no differences between the Iranian and Caucasians in dental measurements but in female 17 years old group Iranian girls had more procumbent lower incisors in comparison with 17 year old Caucasian girls.

Background & Aim: Many patients refer to dentists for bleaching discolored tooth. Regarding the different uses of composite and bleaching for esthetic purposes, this study investigated the effect of three bonding systems (Acetone based, alcohol based, water based) on shear bond strength of composite to bleached enamel.Method & Materials: 30 human intact premolar teeth extracted for orthodontic reasons were used for this experimental study which were mounted with self-cured Acryle 2mm below CEI and divided into 6 groups each group containing 5 specimens randomly. Silicone discs were used for smoothing buccal and lingual surfaces. In the 1st group, after bleaching with 35% Hydrogen Peroxide, composite cylinders with 2mm height and diameter were bonded to buccal and lingual surfaces with Scotch bond-Mp. In the 2nd group, all specimens stored in Physiologic Serum for 10 days after bleaching, and then bonded with Scotch bond-Mp. In the 3rd group, all specimens bonded with Excite bond immediately after bleaching and in 4th group, all specimens stored in Physiologic Serum for 10 days after bleach in and then bonded with Excite. In 5th group, all teeth bonded with Stae immediately after bleaching. And all specimens stored in Physiologic Serum for 10 days after bleaching and then banded with Stae in 6th group. SBS of the groups was measured with an Instron machine with speed of 0.5 mm/min after 24 hours. Results: Shear bond strength of the first group was 16.71±1.54Mpa, for the third and fifth groups it was 36.14±2.12 Mpa and 19.26±1.75Mpa respectively. It was 22.44±1.90Mpa, 35.35±2.56Mpa and 30.57±5.13Mpa in the second, fourth and sixth groups respectively. The overall significant differences existed among the groups (ANOVA test, P<0.0001). The t-test showed a statistical difference between the first and second groups and also the fifth and sixth groups (P<0.0001) but there was no statistical difference between the third and fourth groups (P>0.463).Conclusion: The results of this in vitro study indicated that the shear strength of composite resin to bleached enamel with alcohol - based dental bonding agents was more than Acetone-based and water-based bondings. Also it was possible to bond with alcohol-based bondings immediately after bleaching but there must be a post bleaching stage of 10 days when water-based or Aceton-based bondings were used.

Background & Aim: There are several regenerative procedures for treatment of vertical defects of alveolar bone, including variety membranes and bone grafting materials which have been reported various results. The aim in this study, was to compare clinical effects of two different membranes (palatal connective tissue and collagen) in combination with Bio-oss in treatment of interdental vertical defects.Method & Material: 15 patients with mean age of 40 (8 females, 7 male) that they had at least a pair of vertical interdental defect with attachment loss≥5 mm, initial osseous defect depth≥3 mm. Each defect randomly placed in test or control group. Both groups received Bio-oss, in the test group, palatal connective tissue used as a membrane, in the control group, collagen membrane was used. Quantitative variables including probing pocket depth, clinical attachment level, position of gingival margin, bony defect depth, position of alveolar crest. Mobility before surgery and 9 months after treatment in re-entry procedure was measured.Results: After data analysis, it was shown that, after treatment, considering all of the variables, in each group, there were significant improvement, but there weren't any statistical differences between two groups.Conclusion: We didn't observe any significant difference between clinical effects of palatal connective tissue and collagen in combination with Bio-oss in treatment of interdental vertical defects.

Aim: The aim of this study was to determine the incidence of oral manifestations in HIV infected patients referred to Imam Khomeini Hospital and a private clinic in Tehran during 2001-2002.Method & Material: The study conducted descriptively based on observation, interview and informational questionnaire on 77 patients. The questionnaires included information about history of the patients, oral clinical exams by dentists and physical examination by a specialist in infectious diseases along with evaluation of the results of paraclinical exams (CD4 count, WBC count, lymphocyte count CD4/CD8).Results: The study showed the highest prevalence of the disease in males (84.4%), age group of 30-39 (42.2%), under diploma educational level (53.2%), and non-civil servants (59.7%). The most common way of transmission of the infection was IVDU (48.1%) and the highest prevalence stage of HIV was ARC (79.2%). The highest prevalence of oral manifestations were periodontal diseases (61%), psudomembranous candidiasis (37.3%), herpes simplex virus (26%), recurrent aphtous ulcers (26%), angular chelitis (22.1%), erythmatous candidiasis (15.6%), oral hairy leukoplakia (14.3%), red bound gingivitis (7.8%), acute necrotizing ulcerative gingivitis (6.5%), abnormality pigmentation (6.5%), salivary and gland disease (2.6%), Immuno Thrombocytopenic purpura (1.3%), herpes zoster virus (1.3%), others (1.3%) and dry mouth (62.3%). In the preclinical tests 54.4% were CD4<500 cells/mm3 and the average percent of lymphocytes was 32.25 and the average count of CD4 lymphocytes was 403.59. The average count of WBC was 6682.5 and the average of CD4/CD8. was 0.74409.Conclusion: Highest prevalence of HIV infection was observed in males, age group of 30-39, IV drug abusers, prisoners and travelers to high - risk areas. The most frequent stages of the disease were ARC (pre AIDS) and AIDS respectively.

Background & Aim: Recently registration of lateral cephalometry in natural head position (NHP) has been recommended. But there are few longitudinal studies on its long-term reproducibility. The purpose of this study was photographic estimation of 3 year reproducibility of NHP in adult cases.Material & Method: This was a longitudinal descriptive study performed on 27 volunteer dental students with 19- 29 years of age during 1997-1998. Excluding criteria consisted of congenital and TMJ disorders, history of previous orthodontic treatment, orthosurgical or reconstructive surgery. Three photographs in NHP were taken. The second one (T2) was taken 4 to 10 minutes after the first photograph (short term period) and the third one (T3) was taken with an average of 2 years, 6 months and 9 days after the first one (long term period). They were taken by one technician using a single cephalometric device in standing position by means of a mirror in order to decrease the effect of confounding variables as much as possible. After superimposition of photographs registered on the true 11 vertical line, the angle between true horizontal line from N and N'-Pog' line was calculated. The mean, SD, confidence interval of the angles, short and long term ME, correlation of the angles by time and sex difference were analyzed.Result: Short term reproducibility was 1.78 degrees and long term was 6.60 degrees. There was a significant correlation between changes of the angles during time, which decreased respectively [r(T1/T2)=0.918; r(T2/T3)=0.538; r(T1/T3)=0.478). There was a significant difference between male and female samples only in the second registration (T2) (p<0.045).Conclusion: NHP reproducibility decreases significantly after 3 years and it becomes one third of its short term value; nevertheless there is a significant correlation between its variations during a 3 year period.

Background & Aim: Regarding to prevalence of gingival recession, A variety of surgical techniques have been used to cover recession type defects. Outcome of treatment in almost all of techniques was evaluated by means of coronally positioning of the midbuccal point of marginal gingival. We tried to introduce the new approach for measuring the denuded root surface area as treatment outcome.Methods & Materials: Denuded root surface area was calculated with AutoCad software by means of S points of gingival margin (M, M-1/5, MB, D-1.5, D), acrylic stent, Williams probe and caliper.Results: This technique calculated covered root surface areas without any complicated imaging.Conclusion: This study suggests the use of the new method to evaluate the outcome of root coverage procedures because of its facility, low price and high resolution. Further studies are needed to verify this method.