Journal of Dentistry, Shiraz University of Medical Sciences
Volume:9 Issue: 1, 2008

Statement of Problems: Incomplete therapy of periodontal diseases treated with scalling and root planning (SRP) has been resulted in improvement of host- modulated therapy (HMT) as a new method. Introducing an adjunctive therapy in addition to SRP in managing of destructive preiodontal therapy was the main purpose of this study. Fifteen patients suffered from chronic periodontitis were randomly assigned to test and control groups. Treatment consisted of: SRP+ placebo (control group), SRP+ low dose doxycycline (LDD) twice daily for six months (continous LDD), and SRP+LDD twice daily for first and third two months after completion of phase I (cyclic LDD). Gingival indices including: probing depth (PD), clinical attachment level (CAL), modified gingival index (MGI), and O’leary plaque index were measured and recorded at baseline and at one and six months after the completion of therapy. The data were analyzed using one-way ANOVA and Kruskal-Wallis tests.Probing depth reduction in both of LDD groups were significantly greater than control group (p<0.01). However, this reduction happened between baseline and follow-up oppointments. In other word, the differences between the 1-and 6-month evaluation were not significant (p=0.25). Continous LDD regimen showed an additional PD reduction (from 5.40 to 2.06mm) for pockets greater than 5mm in comparison to the other groups. Within the limitation of this study, the results showed that adjunctive continous and cyclic regimen of low-dose doxycycline can improve the clinical efficacy of conventional therapy, even in patients with less than favorable plaque control.

Sodium hypochlorite is used as an endodontic irrigant for different purposes. Since it is a strong oxidizing agent it might inhibit the resin polymerization. The objective of this in vitro study was to compare the effect of NaOCl on sealing ability of total etch and self etch bonding at different time intervals after root canal therapy. The roof of the pulp chambers and roots (1-2 mm below furcation) of eighty human first molar teeth were cut and pulp tissues were completely removed. Teeth were divided in two groups (n=40), based on the type of used adhsive; total etch (Scotchbond Multi-Purpose plus) and self etch (Clearfil SE Bond). Immediately, chamber pulp of ten teeth of each group were restored with resin composite (control groups). Thirty teeth in each group were treated with 5% NaOCl for 5 minutes in the chamber pulp and restored with resin composite associated with each bonding agent (Z100, Clearfil Photo Core) in three intervals: immediately, one, and two weeks after irrigation with NaOCl. Fluid filtration method was used for evaluation of microleakage. Data were statistically analyzed using ANOVA and T-test (α =.05). Type of dentin adhesive and different time intervals after NaOCl application and restoration, did not show any significant effect on microleakage value (p>0.05). The variable of using and not using of NaOCl showed significant difference on microleakage value (p<0.05). NaOCl treated samples demonstrated significantly higher microleakage. Irrigation with NaOCl during root canal therapy has a negative effect on microleakage of resin composite restorations. Delayed time for restoration did not remove the negative effect of NaOCl.

Surface changes of ceromers caused by tooth brushing are well established, meanwhile they have been improved and are now widely used for various kinds of prosthetics restorations. These materials have lower surface hardness than porcelain and may induce discoloration due to surface roughness. Since it is an important clinical problem, more investigations are needed to evaluate their surface roughness. The aim of this study was to evaluate the effect of tooth brushing on abrasive wear and surface roughness of two current used ceromers. Ten specimens of each type of the ceromer (Belleglass and Gradia) were prepared. All the specimens were examined and surface roughness (Ra) of each was recorded. Then tooth brushing abrasion test were performed with 500 gr weight applied, using a dentifrice containing calcium carbonate as the abrasive material. The surface roughness of each specimen after 20000 strokes were determined with Talysurf 10. Data were analyzed with two sample T test and non parametric Wilcoxon test. Mechanical toothbrushing decreased the surface roughness of Gradia (p<0.05), but did not have any effect on the surface roughness of Belleglass (p>0.05).The results of this study showed that Belleglass is more resistant to abrasive wear but Gradia is a more polishable ceromer.

The most common impression techniques used in fixed prosthodontics are one and two step with spacer. Sometimes impression details are not registered and as a result, use of second wash would be necessary. The aim of this study was to evaluate the effect of second wash of speedex impression material on dimensional accuracy of stone model in one and two stage impression techniques. In this experimental study, two metallic dies (with and without undercut) were used. Impressions were made using four techniques (one step, one step with second wash, two steps, and two steps with second wash). For each technique the impression taking was repeated 15 times and totally 60 impressions were provided. Impressions were poured with Vel-mix stone. Height and diameter for each die as well as distances between the dies were measured by sterio microscope and data were analyzed using ANOVA and T-tests.This study showed that in all four techniques height of dies with undercut was increased, but in the two step technique, the difference was not statistically significant (p= 0.282). In one step and two step with second wash technique, heights of dies without undercut were increased, while in the other two techniques they were decreased. In two step technique, diameters of the two dies were increased, while in other techniques they were decreased. In the two step technique, the distance between the dies was decreased, mean while other techniques did not show any increase and the differences were not statistically significant (p<0.05).The two step technique was more accurate than the other techniques. The one step with second wash technique was more accurate than one step technique. The use of two step with second wash technique is not recommended in fixed partial dentures, but in single crowns it can be used only with special considerations.

Statement of problems: One of the first observation which should be considered in patients during the setting of anterior teeth is the relationship between the anterior teeth midline and the midline of the face. In situations, when the anterior teeth midline is not in favorite relation with the midline of the face, for the resean that the incisal plane of anterior teeth is not parallel with the interpupillary line, unpleasant teeth to face relationship will be present.

The purpose of this study was to determine a relationship between the midline of central incisors with some landmarks of the face and mouth to make use of them in full denture construction.

In this cross sectional descreptive study, 110 individuals including 85 males and 25 females with the mean age 21.5 years were selected. The inclusion creiteria were no extracted teeth, no orthodontic therapy and no esthetic surgery on the nose and face. After examining and completing the questionnaires, impressions were made of both arches using alginate impression material. After preparation of the casts, the relationship of both upper and lower teeth midline, upper central incisor midline to incisive papilla, the midline of filtrum, and labial frenum were examined and the results were recorded. Then the central and deviation parameters in population including average and variance in different percentages were compared.In 62.7% of individuals, the maxillary teeth midline was adapted with the center of incisive papilla. In 37.3% of individuals, the maxillary teeth midline was coincided with the philtrum. In the same percent of individuals, the maxillary teeth midline was at the same line with the upper lip frenum. In 10.9% of individuals, the mandibular dental midline was adapted with the maxillary dental midline. In 3.36% of individuals, the maxillary and mandibular dental midlines and philtrum were adapted.The results of this study showed that it would not be possible in most cases to construct complete dentures in which all landmarks of the face and mouth be coincided with the midline of the anterior teeth.

Statement of problem: One of the major problems of all-ceramic restorations is their probable fracture against lateral forces. However there is not enough information about fracture strength of various all-ceramic restorations.Propose: The aim of this experimental research was to compare the fracture strength and the most probable fracture points in all-ceramic restorations. In this laboratory-based experimental study, 10 symmetric crowns from each IPS Empress2 and IPS e.max press system were constructed on a laboratory model for maxillary central incisor with 2mm occlusal reduction and deep chamfer finishing line. The core thickness was between 0.7-0.8 mm and porcelain was placed over the core using the layering technique. Each of the crowns was cemented onto the dye using Dual cure Variolink II cement and were imposed to compressive forces in Universal testing machine (V=1mm/min) at 30 degrees angle in palatal surface until the fracture occurred. Then the samples were inspected for fracture points by observation. The statistical evaluations were done with Independent Sample T-test (α=0.05). The average force leading to fracture was 385 N (SD=79/96) for IPS Empress2 and 380 N (SD=106/28) for IPS e.max press. The most common fracture points in two groups were the incisal edge and buccal surface. There was no meaningful statistical difference in fracture force between the two systems (P>0.05).The findings of this research indicated that there is no meaningful statistical difference between these two systems in their fracture strength.therefor they are both suitable for constructing anterior all-ceramic restorations.

gastro-esophageal reflux disease (GERD) occurres when there is an insufficiency of the lower esophageal sphincter. The effect of chronic exposure of the oral cavity to gastric acid can be many and varied. The purpose of this study was to evaluate the oral and dental manifestations in patients with GERD, and compare them with healthy persons. In this descriptive and cross-sectional study, 80 patients with GERD, identified by gastroenterologisit, and 80 healthy persons were included. Persons in both groups were asked to answere questionnaires including name, age, consumption of drug, diseases, allergy, bruxism, smoking and dysgeusia. They were also examined for missing teeth, dental erosion and atrophic glossitis. Data were analysed with the spss- 11.5 statistical software by using Mann- Whitney and Chi- square tests.There was a statistically significant difference among two groups for the prevalence and severity of type S2 of dental erosion. (in order Pv=0.045, Pv(S2)= 0.012). No relationship was found between GERD and oral changes including missing teeth, dental sensitivity, dysgeusia, atrophic glossitis and severity of dental erosion (S1, S3) (Pv> 0.05)Moderate dental erosion is a common finding in patients with GERD and should be considered as oral manifestation of this disease.

Polymerization shrinkage stress is the most important causal factor in the microleakage of composite restorations. Relief of this stress with application of low intensity light and low elasticity liner may lead to a decrease in microleakage. The aim of this study was to evaluate the effect of light intensity and flowable composite on the microleakage of class V microhybrid composite restorations. In this experimental study, 56 intact bovine incisior teeth were selected. Standard class V cavities were prepared in buccal surfaces and the teeth were randomly divided into 4 groups of 14. All teeth were restored with Tetric ceram and Excite was used as bonding system: Group 1: conventional cure with 40 seconds 550 mW/cm2 light intensity. Group 2: soft- start (s.s) cure with initial intensity (10 seconds 150 mW/cm2) and then final intensity (30 seconds 550 mW/cm2). In groups 3 and 4: the same curing methods were as groups 1 and 2 perfomed, but flowable composite (Tetric flow) was used as liner. After 24 hours water storage samples were, thermocycled, and were immersed in 2% methylene blue for 24 hours. Dye penetration was evaluated using stereomicroscope. The statistic analyses were performed by Kruskal-Wallis and Mann-Whitney tests In general, the gingival margins had significantly more microleakage than the incisal margins (p<0.05). Microleakage at gingival margin significantly increased with application of flowable liner and soft-start curing (p<0.05). The result of this study indicated that soft start curing and flowable liner significantly increase microleakage at the gingival margin.

Inferior alveolar nerve block is a common technique for anesthetizing of the primary mandibular molars. A number of disadvantages has been associated with this technique, longtime anesthesia might make the child to bite his/her tongue and lip. Periodontal ligament injection could be considered as an alternative method for inferior alveolar nerve block. The purpose of this study was to determine the effectiveness of periodontal ligament injection compared with mandibular block in treating mandibular primary molars. Design of this study was sequential double blind randomized trial. The study population consisted of 82 cooperative children aged 3-9 years old, requiring the same type of treatment on contralateral mandibular molars. Bilateral identical dental procedures were performed on each patient during the same appointment. Signs of discomfort included body and eye movement indicating pain, verbal complaint, and crying (SEM scale), were evaluated blindly by a dental assistant who was not aware of the two groups. The data were analyzed by T- test.Success rate was 91/46 and 92/68 in periodontal ligament injection and mandibular block technique respectively. No statistically significant difference was found between the two anesthetic techniques.Results showed that periodontal ligament injection can be used instead of inferior alveolar nerve block in treating mandibular primary molars

Bifid mandibular canal is almost a rare anatomical variation and can be of considerable interest for the dentists. This condition can lead to complication in performing mandibular anesthesia, surgery of the lower third molar, orthognatic or reconstructive mandibular surgery, placement of dental implants and prosthesis, bleeding, and traumatic neuroma. Therefore, paying attention to this condition seems necessary. In this article, two cases of bilateral bifid mandibular canal are reproted.