Journal of Mashhad Dental School
Year:2002 | Volume:25 | Issue:3-4|Papers Count:19

Introduction: In this study, the relationship. Between the dental treatment needs and socioeconomic classes in young teenagers in Mashhad school children were investigated. Materials and Methods: A group of 400 Children (200 male, 200 female) in 11-14 yrs of age were examined. These cases were selected in random sampling manner. WHO criteria were used for the examination and diagnosis of caries.Results: Unmet Restorative Treatment Need Index (UTNI) was 86% for all of these children. The general dental treatment need (restoration and extraction) was 93.25% According to their socioeconomic status, the subject from the higher levels or classes (1,2) had less restorative treatment need on comparison with other class (3-5). (18/7% v 44/5).This relationship was significant (p<0/05). From 93 percentage of their general dental treatment needs, only 24% was for higher socioeconomic levels (l,2) and 69.25% for lower levels (3-5). The relationship Was significant (P<0/05).Conclusion: The relationship and socioeconomic levels, in this significant. A program as a (PHC) activity in school levels.

Introduction: This study was performed to determine the effect of two kinds of post dam (one created in laboratory and the other in clinic) in increasing the retention of upper complete denture and comparing it with a non-post dam condition.Materials and Methods: 10 patients were selected with good general health condition, a good and undercut- free tuberosity and without palatal tori and surgical scars. For each patient three bases were made: 1- Base without a post-dam.2- Base with a laboratory- post dam.3- Base with a clinical post dam.The face necessary for breaking the posterior sel for each group was measured. statistical analysis of the results revealed that:Results: 1- Group 2 and 3 were more retentive than group 1 2- Group 2 was slightly more retentive than group3, aConclusion: Although group 2 was more retentive than 3, a clinic- made post dam can be more advisable because of its anatomical more favorable relationship with patients' oral soft tissues.

Introduction: Root canal treatment and final restoration are usually not completed in one visit. Therefore to prevent contamination and ingress of oral fluids and bacteria into the root canal access cavities must be sealed after obturation and before final restorations with temporary restorative materials. In this invitro study the sealing ability of four temporary restorative materials was compared. (1. Coltosol 2. Cavit 3. Citodur 4. Cavtemp.) Materials and Methods: Standard access cavities were prepared in sixty-six human molar teeth. The were randomly divided into four groups of 15, with three positive and three negative control groups. The four experimental groups were based on the material used to restore the pulp chamber After placement of temporary restorative materials in an incremental manner. The teeth were thermocycled and evaluated for marginal microleakage unig 2% methylene blue dye, and longitudinal sectioning technique with the aid of stereomicroscope.Results: Cavit showed less leakage than the other materials. Cavtemp showed significantly gearter leakage than all other groups.

Introduction: The purpose of this invitro study was to investigate the effect of two disirifectants on I.A and C.A dimensional changes of casts after impression whit condensation silicones.Two variables are reffered to as: response and explain response; variables were including Dimensions of Cross Arch (C.A). and Inter Arch (I.A).Explain variables wer inducing disinfectants of 2% Acid Glutaraldehyde (G), 1%- 5% sodium hypochlorite (H). Impression materials consisted of Hydrophobic condensation silicone, speeded (S) and hydrophilic condensation silicone rapid (R).Materials and Methods: A mandibullar dentoform was selected.mesiolingual cusps of 717 and incisal edge of l1 were reduced. In reduced areas, 0.4 mm depth and 14.6 mm diameter sacure shape reference points we stablished: Fifteen impressions were made with each material of each group. 10 of 15 impressions Were disinfeded with 2% acid glutaraldehyde, and 0.5-1% sodium hypochlorite While the other5 impressions in the group, served as control. All of impressions were kept in room temperature for 30 minutes. Finally, control groups were poured by type IV gypsum while experimental groups immersed in disinfectants for 30 minutes and then were rinsed under water and poured with gypsum. (CA and LA) Dimensional measurements were done with three dimensional measuring apparatus (C.M.M).statistical data analysis with 95% significance Was done by one way and multivariate ANOVA arid Duncan Test. The results are as fallows:Results: There was not any significant difference in dimensions between the control groups (SC,RC).2- Percent dimensional relative changes were. smaller than (Zero). 3-Statistically,There was not any interaction between two factors (impression an material and disinfectant).4- By eliminating the impression material factor, there was a significant difference in two disinfectants on CA dimension. it means that (H) created more quartettes than (G).5- By eliminating the disinfectant factor, there was a Dimension. It means that Speedex created more quantities than raped.Conclusion: Comparison of six subgroups collection showed:*I.A dimension didn't have a significant difference in subgroups.Not be of concern for a long span bridge and removable partial denture.**C.A dimension is an important factor for removabletion for impression were SH.RH and SG, respectively.

introduction: The neutral zone is advised set the teeth in a denture, Although the crest of the being used for the mentiond purpose by the dentists.To compare these two patterns, 20 patients were Chosen; 6 Women with The average age of 51 and 14 men with the average age of 54.Materials and Methods: Like an ordinary case, a primary impression was taken, a special tray was made desiring a suitable wax rim. After border molding of the special tray, the final impression was taken.In the next stage the buccal and lingual surfaces of the Wax rime Were coated by alginate paste and placed into the patient's mouth to record the neutral zone. The patient was directed to move the related muscles into function.After casting the final impression, the buccal lingual surfaces of impression were also recorded by plaster.The midpoint of the center of the ridge and the center of the neutral zone were pointed and measured. After listing, the final result were observed:Results & Conclusion: 112 cases the midpoint zone lies on the lingual slope of the ridge and in buccal slope. In 18 cases There coincide on each other.

Introduction: The Purpose of this study was to evaluate the histological effects of local injection of dexamethasone on periodical tissue inflammation following root canal treatment in cat as the variables the extent of inflammatory cell infiltration, edema and vasodilatation were assessed. 64 mandibular canine teeth from 32 healthy cats were used at 6, 12 and 24 hour intervals as follows:Materials and Methods: 1)The experimental group included 24 cats. each cat lower right canine too received a sub mucosal injection of 4 mg dexamethasone 30 minutes prior to the root canal treatment. Lower left canine tooth was also evaluated to assess the systemic effect of the dexamethasone injection to the lower right one.2) The positive control group included 6 cats in which both lower canines were treated endodontically without dexamethsone injection.3) The negative control group included 2 Cats with neither dexamethasone nor root canal treatment.The animals were scarified using the vital perfusion technique. Following block preparation, 5µm diameter sections were cut and stained using the H&E staining and examined by a calibrated pathologist using light microscopy.Results and Conclusion: There was no statistically significant difference on the evaluated parameters between the groups in terms of local and systemic effects of dexamethasone. Local injection of dexamethasone decreased the edema at 12 hour interval, and the inflammatory cell irifiltrate by 24 hour interval the extent of infilitratration, edema and vasodilatation were statistically different among the positive and negative control groups. Infiltration was different at all intervals and edema was different at 12 hour interval from others.

Introduction: Juvenile periodontitis is a kind of periodontal disease which makes changes in radiographic uppearance of teeth prior to apparent clinical manifestations. Early diagnosis and appropriate treatment prevents teeth loss wasting away of the teeth.Materials and Methods: Fourteen patients with Juvenile periodontitis (11 female and 5male subjects) aged between 11 and 20 years were evaluated radiographically in this study using the long cone paralleling technique and the bone loss was detected of measured.Results: The results showed that the greatest bone loss occurred around molar teeth and it was more pronounced at mandibular compared to maxillary molars.No significant difference existed between the two sides (right of left) of the dentition and this was true for both mandibular and maxillary arches. It was also observed that tooth loss has a direct relationship with the patient's age.Conclusion: The results revealed that first mandibular molars are most of effected. This could be because of these teeth being as the first permanent teeth in jumans.

Introduction: Evaluation of effect of different posts arid composite restoration on strength of endocontically premolar teeth. Materials and Methods: 90 intact Premolars were selected thirty, as the control group was the experimental group. Control group was divided to three group of ten.One group of ten as Positive (intact teeth) and two groups < of ten as negative (Prepared teeth for class I and II).After RCT, extended class I and II cavity preparation with 3 millimeter Buccoligunal distance were divided to two groups on the basis of class I and II composite restoration.Then each group was divided into three subgroups, On the basis of the type of post:(parapost = P, Bioglass Post= B and composite Post=C).After treating the coronal and radicular Dentin with Scotch Bond Multi Purpose (3 MCo), Parapets was put in to the 2-3 of canal length with a self cured composite (Medental, McAllen), while Biogalss and Composite posts were put in vivadent and self cured composite (Medental, McAllen) After 500 thermal cycling, Breaking test was done with a semi spherical crosshead speed of 5 mm/min.Analysis of data was done by ANOVA, Duncan test and Mann- whiney test with 95% significance level.Results: 1-Mean strength for class I and II restorations were respectively 101.8 and 89.9Kg 2- Mean strength for posts (B, Cand P) were respectively: 95, 48-101.24 and 90.88.Kg 3-There was not a significant difference in strength of restored teeth between class I and II composite restoration4- Strength of teeth significantly increased by post insertion.5-Intact teeth were significantly stronger than experimental group.6-The strength of restored teeth was 50% of intact teethes strength:7-Class I restored teeth were 183% more stronger than teeth with class I cavity prep.8-Class II restored teeth were 56% stronger their teeth with class II cavity prep.Conclusion: If posts are used in endodontically premolar teeth by adhesive technician, and composite is used for restoration, they will have successful clinical performance.

Introduction: The Purpose of this inviro study was to evaluate the porcelain veneer to Ni-Cr Beryllium bond strength by different adhesives.Materials and Methods: 80 Casting models were molded; Each model had a cylindrical shape With two different diameters Larger diameter was used for adhesion the porcelain. After molding in self cured acrylic resin, the surface of samples was air abraded. Then specimens were divided into four groups of twenty. group C (Control): Aluminum foils were selected In mid part of each foil a 3.5mm diameter hole Was punched. Then they adapted on surface of model. Finally, Porcelain firing Was done. For experimental groups, 60 porcelain disks with 2mm thickness and 3.5mm diameter were made similar to P.E.M disks. But aluminum foils were put on refractory sheet. Surface treatment for porcelain disks was done with sandblasting and silane coupling agent.Group S: Firstly, SBMP adhesive was used in alloy surface. Then disks Were bonded with Duo Cement.Group P: Panavia 21 was used for porcelain alloy bonding.Group 0: firstly, One Coat Bond adhesive was used in alloy surfaces. Then disks were bonded with Duo Cement. breaking of samples was done by blade cross head with the speed of 2mm/min.ANOVA & Duncan and I tests with 99% significance level were used for data analysis. Results:Results: 1- Data mean for bond strength of groups C-P-S-O were respectively 25-19.5-15.5 and 13 MPa.2-In Comparison of group C bond strength with each of experimental groups, PFM showed greatest bond strength but had the least difference from group P.3- In Comparison of experimental groups, P had the greatest bond strength and showed a significant difference among with group O. While P and S had no significant differences.4- In Comparison among four groups, C had significant difference with all of experimental groups, while P showed significant difference from O. Conclusion: If facial surface of casting crown exposed porcelain, alumina air abraded as, has greatest bond strength with panavia 21 and then with (SBMP+ Duo Cement).

Introduction: Hereditary gingival hyperplasia is a rare condition with undetermined etiology, and thus the hyperplasia is designated as idiopathic, A study of several. families revealed pattern of inheritance to be autosomal recessive in some cases and autosomal dominant in others. The enlargement usually begins with the eruption of the primary of secondary dentition and may regress after extraction. The enlarged gingival is pink, firm, and almost leathery in consistency and has a Characteristic minutely Pebbles surface.Results: The hyperplastic gingive deflects the erupting teeth from proper alignment. Microscopic features of gingival enlargement shows a bulbous increase in the amount of connective tissue that is relatively avascular and consists of densely arranged collagen bundles and numerous fibroblasts; The surface epithelium is thickened and acanthotic, with elongated rete pegs. Surgery is the treatment of choice in such conditions.Materials and Methods: In our study, in Mashhad Dental School, a group of family members in three generations were followed for almost 23 years.Conclusion: Surger is the treatment of choice in such condition. This clinical and histological study was initiated in the oldest member of the group by extraction of remaining teeth and excision of enlarged gingiva. No recurrence happened after 23 years of follow up. The other cases were operated surgically twice during the primary and permanent dentition periods.After the first surgery, the recurrence of gingival enlargement was a common finding in all cases, especially some years after completion of perm anent dentition.

Introduction: Sterilization is defined as a procedure by which objects become free of any viable organism. Disinfection is the process of destroying the microorganisms of the surfaces of solid objects. however, this is not necessarily identical to destruction of the microorganism spores. Antiseptic procedure is a method, during which a chemical is kept in contact with living tissues such as skin and mucosa and causes reduction, inactivation; or destruction of microorganisms. The mechanism of action of antibacterial agents could be through either damage to the DNA, destruction of the proteins, disruption of the cell membrane of cell wall, cleavage of soldierly groups or chemical competition.) Results & Conclusion: With an overview of various sterilization methods, it is readily conceivable that among the physical methods, the use of autoclave is still one of the best and most reliable sterilization techniques. To avoid the potential problems of this method, other methods such as dry sterilization (oven) could be used istead. Regarding the chemical methods; only 2% and 3% solutions of glutaradehyde solutions of micro -10 are capable of sterilization. Other chemical agents could be used either as disinfectants or antiseptics.