Journal of Dental Medicine

Quantitative evaluaiton of porphyromonas gingivalis before and after non- surgical periodontal treatment in deep pockets of patients with aggressive periodontitis

Z. Kadkhoda

Statement of Problem: Elimination of porphyromonas gingivalis (p.g) from subgingival area in order to successfully treatment out comes in patients with Aggressive periodntitis AP is necessary.

Purpose: The aim of this study was the evaluation of non-surgical treatment efficacy in reduction of bacterial population in deep pockets.

Materials and Methods: In this randomized clinical trial study we evaluated the result of non- surgical therapy on reduction of p.g count from deep pockets of patients with aggressive periodontitis that had at least one (p.g plus) deep pocket (>5mm) in each quadrant. At first stage of non-surgical treatment intra pocket irrigation with chlorhexidin was done after scaling and root planning for all patients. In second stage (one week later) antibiotics including amoxicillin- metronidazol prescribed for ten days. At base line, one, six and twelve weeks after beginning of therapy, microbial samples, plaque index, bleeding on probing index and probing pocket index were recorded.

Result: There was statistically important difference between one and six weeks after treatment with base line in colony count of p.g and all of clinical indices. But in 12 weeks after therapy just, PI and PPD had statistical difference with base line. In this stage, colony count and BOP was reduced but this reduction had not statistically important difference with base line.

Conclusion: Thus in present study our non- surgical strategy in elimination of p.g and clinical improvement was successful in short time but three month after therapy recurrence of disease happened in some patients.

Clinical evaluation of endodotic therapy on periodontal tissue healing in chronic advanced periodontitis

R. Sadeghi

Statement of Problem: There is a controversy about the relationship between pulpal and periodontal diseases. The interrelationship between pulp and periodontium could have an important effect on the treatment plan of the tooth.

Purpose: The aim of the present research is to evaluate root canal therapy effects on periodontal healing of teeth with chronic advanced periodontitis.

Materials and Methods: In this randomized controlled clinical trial 32 single rooted teeth which had necrotic pulp or irreversible pulpitis in 7 patients with chronic advanced periodontitis were selected based on specific criteria. Using a split mouth design, teeth were randomly put in two groups of test and control. In the test group root canal therapy ,scaling & root planing were done.In the control group, only scaling & root planing were performed. Clinical parameters including Pocket Depth (PD), Clinical Attachment Level (CAL), mobility, pattern of bone destruction and plaque index (PI) were evaluated in two groups at base line, 1 and 3 months after treatment. Appropriate tests such as paired Wilcoxon and Mann-Whitney were performed.

Results: Statistically significant reductions were found in the test group when comparing baseline and one-month post treatment values for Clinical Attachment level (CAL) but not after 3-months. In the control group the CAL reductions were not statistically significant between baseline and one month post-treatment, but a increase were observed between one month and three months after treatment. There was a statstically significant difference between the test and the control groups. Other parameters didn’t show any significant differences in each group and between two groups.

Conclusion: Since clinical attachment level was the most important parameter we found it can high lighted the role of pathogene with pulpal origin in progression of periodeontal disease and it is concluded that beside periodontal treatment in some advanced periodontal cases pulp therapy maybe an effective procedure for eleminating destructive pathogens of pulp and causing periodontal healing.

A survey on the knowledge of health system personel in Ghom province toward oral and dental health

S.J Poorhashemi

Statement of Problem: The accomplishment of oral and dental health is one of the most important goals in preventive dentistry influenced by the people’s knowledge and attitudes. Health system personel are the group able to play the most important role in this field affecting the society under their control directly. Purpose: The aim of this study was to evaluate the knowledge of health system personel, working in Ghom province, about oral and dental health. Materials and Methods: In this descriptive cross-sectional study, knowledge and attitudes of all 187 personel working in the health system center of Ghom province were investigated through a questionnaire including 10 questions on knowledge and 10 other ones on the attitudes of subjects studied. Data were subjected to ANOVA, Tukey and correlation tests. Results: The knowledge of females was higher, compared to males showing a statistically significant difference (P<0.05). There was a positive correlation between subjects’ knowledge and their level of education, age and work duration (P<0.05). Conclusion: Generally, the level of knowledge and attitude of the personel working in health centers in Ghom province was acceptable but not an ideal one and the continuity of training and re-education courses seemed necessary.

A survey on the effects of repeated porcelain firing cycles on the marginal integrity of shoulder porcelain made of noble and base-metal alloys

R. Khodadadi

Statement of Problem: In order to eliminate the esthetic problem of metal collar in porcelain fused to metal crowns various techniques, such as shoulder porcelain, have been suggested.

Purpose: The aim of this study was to investigate the effects of repeated porcelain firing cycles on the marginal integrity of shoulder in porcelain fused to metal crowns, made of two kinds of alloys: noble and base-metal.

Materials and Methods: In this experimental study, four groups of ten brazen models (Die) were used. Metal crowns of groups A&B were made of a noble alloy and those of C&D of a base-metal alloy. Groups A&C had the shoulder width of 1mm and groups B&D had the shoulder width of 1.5mm. After degassing and opaqing, shoulder porcelain was completed in the area of shoulder. At this stage, the average vertical gap of margin was measured by a reflective microscope (400). Data were analyzed using ANOVA and Duncan tests.

Results: No simoltaneouse interaction between the type of alloy and the shoulder width was found (P=0.709). The type of alloy had a significant effect on marginal integrity (P=0.021) attributing the best marginal integrity of shoulder porcelain to base-metal alloys. Shoulder width played also a significant role on marginal integrity (P=0.00) indicating that the reduction of shoulder width would increase the marginal integrity.

Conclusion: According to these findings, the best marginal integrity of shoulder porcelain is achieved through shoulder width of 1mm along with base-metal alloys.

An in-vitro comparison of canal debridement efficiency between three systems of Rotary, Reciprocal and Vertical

MS. Sheykhrezaee

Statement of Problem: Total removal of tissues and remnant microorganisms as well as canal shaping are the essential objectives of endodontic therapy. A successful endodontic treatment is obtained through Shilder’s principals, however complete observation of this technique using stainless steel files manually is problematic and time-consuming. Modern technology, in order to eliminate such problems, has presented new facilities such as Nickel-Titanium (NiTi) files and engine driven instruments.

Purpose: The aim of this in-vitro study was to compare the canal debridement efficiency of three engine driven instruments: Rotary, Reciprocal and Vertical.

Materials and Methods: In this experimental study, 60 mesial roots of human first and second mandibular molars were divided into three groups randomly. In each sample, one canal was considered as case, the other one as control. Files used in Reciprocal and vertical groups were of handy Ni-Ti type and in rotary group, rotary Ni-Ti files were used. After debridement, the roots were sectioned at 3mm and 5mm from anatomic apex, stained and examined under light microscope. Comparison criteria between case and control groups were based on residual debris and predentin and the level of root canal preparation and shaping after debridement. Data were subjected to kruskal-Wallis non-parametric test.

Results: There was no significant difference between the efficiency of debridement at 3mm and 5mm sections between all groups. But difference in time consumption was significant ranked from the shortest to the longest as rotary, reciprocal and vertical.

Conclusion: The efficiency of debridement between the three automated instruments was approximately equal, however the instrumentation time was different between three groups. Rotary system was the fastest one, as compared with reciprocal (second) and vertical (last). It may be concluded that rotary system has a superiority over the other two groups in conventional root canal therapies.

Facial vertical changes among patients treated by Edgewise orthodontic technique along with tooth extraction

F. Heravi

Statement of Problem: Tooth extraction is a common technique in orthodontics and most of the specialists believe that this technique is able to change the facial appearance.

Purpose: The aim of this study was to investigate facial vertical changes in orthodontic patients following tooth extraction.

Materials and Methods: Thirty patients, after their growth spurt, with CLI malocclusion all treated by a specific orthodontist through Edgewise technique along with the extraction of four first premolars were chosen. Lateral cephalograms of patients, before and after treatment were compared and facial vertical changes and teeth were studied.

Results: Anterior and posterior facial heights were increased during treatment. Despite the limited use of intermaxillary elastics, teeth were extruded. The most increase in facial heights was observed in the lower third of face. Patients with longer faces before treatment showed more extrusion of mandibular molars as well as more increase of mandibular slope.

Conclusion: Tooth extraction in orthodontic treatments can not guarantee the decrease or even non-increase of facial height. Among patients with long faces, it is particularly suggested to refrain from the application of extrusive orthodontic forces.

A comparative survey on the increased fracture resistance of amalgam restored teeth using three types of Glass Ionomer as adhesive liners

F. Shafiee

Statement of Problem: Because dental amalgam does not adhere to tooth structure, using adhesive cements in amalgam-bonded restorations have been increased.

Purpose: The goal of this in-vitro study was to compare the effects of three types of glass ionomer as adhesive liners as well as varnish liner in increasing fracture resistance of teeth restored with amalgam.

Materials and Methods: Seventy extracted human maxillary premolars were selected and MOD cavities were prepared on them excluding ten intact teeth as positive control group and ten cavity prepared teeth without restoration as negative control group. All the prepared teeth were then restored with spherical amalgam (gs.80) with one of the following liners silver alloy glass ionomer liner, conventional glass ionomer liner, varnish liner, resin-modified glass ionomer and resin-modified glass ionomer with delayed light curing. The teeth were stored in 37C distilled water for 7 days and were then loaded under compressive strength using an Instron testing machine. The force required to fracture teeth were recorded and the data were analyzed statistically using ANOVA and Tukey HSD tests.

Results: Statistically significant differences were observed in fracture resistance between restored and non-restored samples. Comparisons between groups attributed significant effects to resin-modified glass ionomer in increasing fracture resistance of amalgam restored teeth (P<0.05). In most specimens, one cusp was separated from tooth structure whereas amalgam remained bonded to the intact cusp. Conclusion: According to these findings, resin-modified glass ionomer put a statistically significant effect in fracture resistance of amalgam-restored teeth.

Effects of different designs of implant supported fixed partial dentures on peri-implant bone stress distribution during mandibular-flexture

S. Nokar

Statement of Problem: In the treatment of edentulous patients with implant supported fixed partial dentures several factors such as implant numbers, implant position, superstructure pattern and cantilever length must be considered. Mandibular flexture in function exerts forces in peri-implant bone, however this phenomenon has received little attention.

Purpose: The goal of this finite element analysis (FEA) study was to evaluate the effect of mandibular dimensional changes on peri-implant bone stress in different prosthesis and implant treatment plans.

Materials and Methods: In this experimental study, three dimensional finite element computer model of mandible was simulated according to data from CT-Scan in 0.5 mm sections. The model of 4.110 mm ITI implant, measured by profile projector, was simulated in solid works 2003 software. Implant models were inserted, in two different patterns, on mandible and three different superstructures were placed on implants. Two clenching tasks were modeled (incisal clench and right molar clench).

Results: Analysis of Von Misses stress for peri-implant bone revealed the lowest stress values in three-piece superstructure.

Conclusion: According to this study, additional placement of implants in order to fabricate independent prostheses and to achieve the freedom of mandibular flexture are recommended.

An evaluation on CPITN index in hemodialytic patients in Tehran

Y. Soleimani Shayeste.

Statement of Problem: Hemodialytic patients may be exposed to periodontal diseases during treatment. No information of any kind is available regarding the periodontal treatment needs of such patients.

Purpose: The aim of the present study was to determine the periodontal treatment needs of hemodialytic patients, living in Tehran, to be presented to the public health system.

Materials and Methods: In this descriptive study using CPITN index 75 patients according to multi-stage sampling method and in proportion to the number of patients in Tehran were selected. Following necessary training, qualified subjects were chosen and a special questionnaire was completed for each using personal protection, CPITN index, by WHO prob, was examined and numbered according to (0-4) codes. Results: The findings showed that 10.6% of the patients had normal periodontal status (Code-0), 12% of the patients had bleeding upon probing (code-1), 21.4% had calculus (Code-2), 21% of the patients had shallow pockets (Code-3) and 24% had deep pockets. It was also shown that 89.4% of the patients needed oral hygiene instruction, 77.4% needed scaling and 24% required advanced periodontal treatments whereas only 10.6% did not need any treatment.

Conclusion: No statistically significant relationship was found between periodontal status and factors such as age, sex, the history of hemodialysis treatment and level of patients’ education.

A survey on the effects of three surface treatment methods on bond strength between base-metal alloys and Ceromer material (Targis)

Sh. Rokni.

Statement of Problem: Ceramics and resins belong to the earliest tooth restorative materials. Nowadays new generations of these materials have provided a revolution in cosmetic dentistry. Ceramic Optimized polymer (Ceromer) is a newly made product that the bond between this material and base metal alloys, which are used widely today, is paid too much attention.

Purpose: The aim of this study was to evaluate the bond strength of targis (Ceromer) to three types of base metal alloys through three different surface treatment methods.

Materials and Methods: In this experimental study, ninety plates of Rexillium III, Silver cast and super cast alloys (3050.4) were prepared and surface treated through three different methods (air oxidation, vaccum oxidation and sandblast). All samples were then veneered with 1.mm thickness of Targis. After thermocycling, three-point bending test was performed by universal testing machine (Instron) to evaluate the amount of forces at crack or fracture times in Targis. The type of failure (cohesive or adhesive) was also evaluated microscopically. Statistical analyses were made using 2-factor ANOVA and Duncan tests.

Results: The type of surface treatment method caused a statistically significant difference in force rate required for crack and fracture in Targis. Sandblasting was found as the best method. The type of alloys, in all three methods, had a significant effect just on crack creation attributing the largest amount of force to Rexillium III. Adhesive type of failure occurred mostly in super-cast alloys through air-oxidation method, and cohesive type was more among silver cast alloys and sandblast method.

Conclusion: According to the results of this study, bond strength between Ceromer materials and base metal alloys is significantly great and Rexillium III alloy associated with sandblast technique the best combination.

An evaluation on time status of functional orthopedic treatment in class II skeletal patients with cervical vertebrae maturation stage (CVMS) index

Z. Dalili

Statement of Problem: Considerable response to functional orthopedic appliances treatment in class II skeletal patients occurs during pubertal growth spurt. Therefore, it seems necessary to investigate indices indicating mandibular growth pattern. It has been proved that analyzing cervical vertebral maturation stage is a more valid index than that of hand wrist.

Purpose: The aim of this study was to evaluate the time status of functional orthopedic treatment in class II skeletal patients using CVMS index.

Materials and Methods: In this descriptive-inferential study, lateral cephalometric radiographs of 153 class II skeletal patients with mandibular deficiency, before treatment, were studied by an oral and maxillofacial radiologist using the index of cervical vertebral maturation stage (CVMS) and were categorized in three phases: CVMS I (desirable phase of treatment), CVMS II (ideal phase), and CVMS III (undesirable phase of treatment).

Results: Statistical analysis ranked the prevalence of treatment phases as: 41.8% in desirable phase (CVMS I), 28.1% in ideal phase (CVMA II) and 30% in undesirable phase (CVMS III). No significant differences were found between the three phases using Chi-square analysis. Time status of functional orthopedic treatment was also evaluated based on age and sex. The results showed significant differences between two sexes (P=0.032).

Conclusion: The present study suggests the analysis of CVMS index, along with clinical criteria, in the determination of an ideal time for functional orthopedic treatment to prevent patients’ exhaustion during treatment Period.

A comparison on the mesiodistal width of right and left side teeth in people with normal occlusion

M. Zarringhalam

Statement of Problem: In some cases, a difference in size between the right and left teeth, during band selection for first molars, is observed.

Purpose: The aim of this study was to measure the mesiodistal width and to compare the teeth on left and right sides of jaws in individuals with normal occlusion, according to the sex.

Materials and Methods: In this cross-sectional study, sixty students (30 males and 30 females), age ranging from 16-18 with the mean age of 17.3, were selected through cluster random sampling from Mashhad high schools. The mesiodistal width of 1440 teeth, from the distal of first molar on right side to the distal of first molar on the left, were measured on study casts. Data were analyzed using paired t-test and Independent sample t-test.

Results: In upper jaw, mean of the mesiodistal width of each tooth on the right side was less than its counterpart on the left side except for the right second premolar which its width was more than that of the left one although the differences were not statistically significant. In lower jaw, mean of the mesiodistal width of each tooth on right side was more than the same tooth on the left except for the canines and second premolars. The differences were not significant. Generally the mesiodistal width of each tooth in males was more than its counterpart in females with a specially significant difference for canines and first molars.

Conclusion: According to this study, there was a little difference in me siodistal width of teeth between the left and right sides. In upper jaw, the majority of teeth on the right side were smaller than the left ones whereas in lower jaw the right side ones were larger than the left ones. Therefore, dental asymmetry in both jaws, on the left and right sides, were opposite. Comparing males and females, each tooth in males was larger than the same one in females and especially for canines and first molars the difference was significant. As a result dental asymmetry should be considered in orthodontic treatments.