مجله دندانپزشکی دانشگاه علوم پزشکی تهران
سال بیست و دوم شماره 2 (پیاپی 59، تابستان 1388)

Several surgical approaches have been used to achieve root coverage. The Subepithelial Connective Tissue Graft (SCTG) procedure has been shown to be a predictable means to treat gingival recession. Semilunar Coronally Positioned Flap (SCPF) is a simple mucogingival surgery to cover the exposed root surface without harvesting the palatal connective tissue. The purpose of this study is to compare the outcome of gingival recession therapy using SCTG and SCPF. Forty Miller class I buccal gingival recessions (≥2mm) were selected. Recessions were randomly assigned to receive either the SCPF or SCTG. Recession Height (RH), Recession Width (RW), Width of Keratinized Tissue (WKT), Probing Depth (PD), Clinical Attachment Level (CAL), were measured at baseline, 1, 3, and 6 months after surgery. The data were analyzed using independent t-test and Repeated Measure ANOVA. The average percentages of root coverage for SCPF and SCTG were 88% and 71%, respectively; and the complete root coverage observed were 55% and 45%, respectively. There were no significance differences between the two groups with regard to RW, PD, CAL, WKT (except in the third month after surgery which was slightly greater in SCPF group). RH was significantly decreased from 2 to 6 months after surgery in SCPF group. The findings from this study indicate that if the tissue thickness and initial width of keratinized tissue are sufficient, SCPF may be a good substitute for SCTG in treatment of Miller class I gingival recessions.

The aim of this clinical study was to determine the effectiveness of progressive loading procedures on preserving crestal bone height and improving peri-implant bone density around maxillary implants restored with single crowns by an accurate longitudinal radiographic assessment technique. Eleven Micro-Thread Osseo Speed dental implants were placed in 11 subjects and permitted to heal for 6 weeks before surgical uncovering. Following an 8-week healing period, implants underwent a progressive loading protocol by increasing the height of the occlusal table in increments from adding acrylic resin to an acrylic crown. The progressively loaded crowns were placed in 2 mm infraocclusion for the first 2 months, light occlusion for the second 2 months, and full occlusion for the third 2 months. At forth 2 months, a metal ceramic crown replaced the acrylic crown. Digital radiographs of each implant were made at the time of restoration, then after 2, 4, 6, 8, and 12 months of function. Digital image analysis was done to measure changes in crestal bone height and peri-implant bone density. The mean values of crestal bone loss at 12 months were 0.11 ± 0.19 mm, and when tested with Friedman across the time periods, the differences were not statistically significant (p> 0.05). The mean values of bone density in the crestal, middle, and apical area were tested with Repeated Measure ANOVA across the time periods, the differences were statistically significant (p<0.05). Progressive loading doesn’t cause crestal bone loss. The peri-implant density measurements of the progressively loaded implants show continuous increase in crestal, middle and apical peri-implant bone density by time

In treatment of posterior crossbite awareness of the effects of Haas and Hyrax rapid maxillary expanders (RME) on nasal cavity will help the clinician to select the better appliance. This study was carried out to compare the effects of Haas and Hyrax expanders on the nasal cavity of patients treated for posterior crossbite. A clinical trial study was designed on posteroanterior (PA) cephalograms of 30 subjects to evaluate the nasal cavity width of 14 subjects (8 female & 6 male) with mean chronological age of 12± 2years who received RME with Hyrax type and 16 subjects (9 female & 7 male) with mean chronological age of 11±1.6 years who received Haas type palatal expander. Paired t-test was used to analyze the outcomes of expansion in each group. Student t-test was used to compare Haas and Hyrax groups. The mean value of screw expansion was 9±2 mm in both groups. In Hyrax group nasal cavity width(Nc-cN) increased from 29.2 ±1.94 mm to 31.7 ±1.93mm (p= 0.001) and In Haas group it was increased from 27.75± 2.21 mm to 29.35 ± 2.26 mm(p= 0.043). When two groups were compared to each other, statistically this increase was more significant in Hyrax than in the Haas group (p=0.038). In this study RME affected geometry of the nasal cavity by increasing the nasal cavity width. However In our sample, Hyrax appliance demonstrated better performance over the Haas appliance in all variables.

It is well recognized that implant treatment is common worldwide, but the approach to success is not predictable because of bone loss that occurs around the implants. Also there are many factors affecting crestal bone loss around the implants that one of them is the surgical protocol of implant installation. The purpose of this investigation was to evaluate the amount of crestal bone loss around the Replace implants installed according to submerged and non- submerged treatment protocol. In this study, 11 patients received 34 implants. In each patient (unilateral or bilateral mandible), one of the implants was placed with submerged procedure and in the other one non- submerged procedure was used. In a period of 3 months a temporary partial denture that covered the implants was used. After 3 months the submerged fixture was exposed, impression was performed and fixed prosthesis was fabricated. Loss of crestal bone at each implant was measured. These measurements have been done at surgical times, over a period of 3 months after implant installation and 6 months after the delivery of the fixed prosthesis. The measurement was done with digital subtraction radiography. Data was analyzed by Wilcoxon Signed Ranks test. Three months after implant placement, submerged groups showed statistically more crestal bone loss (0.65±0.71) than non-submerged (0.41±0.53) group (p=0.02). After 6 months the mean value of crestal bone loss in submerged group was 0.21±0.40 mm and in non submerged group was 0.29±0.49 mm. This data indicated no statistically significant difference between the two groups of implants (p>0.05). Our results are in accordance with previously published studies and confirm that the value of crestal bone loss in submerged and non-submerged groups after 3 and 6 months were similar and in acceptable limit

The aim of this investigation was to evaluate the osteopromotion property of homogenous demineralized dentin matrix (HDDM) on experimental surgical bone defects in parietal bone of rabbits using the guided bone regeneration (G.B.R.) technique incorporating Paroguide collagen membrane.

Surgical bone defects were created in 6 Newzland white rabbits (2 defects in each rabbit). The defects were protected by Paroguide membrane alone (control group) or filled with HDDM and protected by Paroguide membrane (experimental group). The HDDM had been obtained from the central incisors of rabbits. The rabbits were sacrificed after 15, 30, 45, 60, 75 and 90 days and the defects examined histologically. Data were analyzed using pair-t test. The level of significance was set at p=0.03.

Histologically, the volume of newly formed bone matrix was significantly greater in the experimental group. No inflammatory reaction was seen in either experimental or control groups.

Bone regeneration was accelerated in the bone defects filled with HDDM in comparison to the control group

In spite of the achievements in the field of dental adhesives, we are facing challenges with dentine bonding resistance, strength and stability. According to recent studies the role of MMP inhibitors in association with bonding,s persistence and leakage reduction and restoration,s persistence is important. The aim of this study was to investigate the effect of doxycycline as a MMP inhibitor on the degree of conversion (DC) of an experimental dental adhesive. In this experimental study, a new dental adhesive blend was prepared by mixing doxycycline monohydrate (in concentrations of 0.0, 0.25, 0.5, and 1 wt.%) with monomers. The monomers were composed of 12% Bis-GMA and 10% TMPTMA, 28% HEMA, and 50% Ethanol by weight for all groups. Comphorquinone and amines were chosen as photo initiator system. Degree of conversion of all adhesives was measured using FTIR spectroscopy. The results were analyzed using one-way ANOVA and Tukey post hoc tests. The results showed that addition of 0.25, 0.5, and 1 weight percent doxycycline did not significantly reduce the DC of the adhesives compared to 0.0% control group (p>0.05%). According to the results of this study, adding doxycycline to the adhesives did not adversely affect the DC.

Several agents were used for pulpotomy in primary molars. Formocresol is the most common drug in this procedure. In some studies it has been shown that, this material has potential some side effects, so it is essential to find other alternatives. The aim of this study was to evaluate clinical and radiographic success rates of mineral trioxide aggregate and formocresol. In this randomized clinical trial study, 70 carious primary teeth of 4 to 7-year-old children were pulpotomized, and remaining pulp was dressed with Root MTA and formocresol. The clinical and radiographic follow up evaluations were performed at 6, 12 months by a blind dentist. The data were analyzed by Fisher's exact test. At the end of 1-year follow-up period, in formocresol group sinus tract and tenderness to percussion were seen in 2 teeth, internal resorption was seen in 1 tooth, and furcation radiolucency was seen in 2 teeth. Clinical and radiographic signs of failure were not seen in any case of (Iranian) Root MTA group. Based on the results of this study, Iranian MTA can be used for pulpotomy in primary molars.

A considerable percentage of failure in Endodontic treatments in maxillary molars is attributed to undiscovered second mesiobuccal canal (MB2).There are different methods for discovering and accessing to this canal. The purpose of this ex vivo study was to compare the detection ability of three methods (direct look, fiberoptic loup and surgical microscope) to find MB2 after troughing with ultrasonic. In this experimental study, we selected 90 extracted maxillary molars (45 first and 45 second molars) in which after access cavity preparation MB2 canal was not discovered by direct vision and endodontic explorer. They were divided into 3 groups (n=30). The dentinal shelf between mesiobuccal and palatal canals was eliminated by an endodontic ultrasonic tip (troughing). After that, first group was searched by direct vision, second group by a loup and fiberoptic light and third group by dental operating microscope. Data were analyzed, specificity and sensitivity were calculated. The results showed that 21%, 61%, and 92% of MB2 canals after troughing was found by direct vision, fiberoptic loup, and surgical microscope, respectively. Based on the results of this study, surgical microscope and loup with fiberoptic are preferred methods for discovering MB2 canal. Troughing with ultrasonic can help find MB2 canal in all methods.

The microbial cause of dental caries has been proved among its multifactorial etiologies. The prevention and control of dental caries is very critical because of high prevalence and cost especially in high risk patient such as xerostomia. Based on the world attraction to traditional treatment and importance of drug extraction of natural materials and plants, in this in vitro study effect of hydroalcoholic extract of Salvia officinalis and Pimpinella anisum which were very useful in traditional treatment of mouth and teeth disease has been determined against cariogenic bacteria. In this experimental study, hydroalcoholic extracts have been prepared from Salvia officinalis and Pimpinella anisum with maceration method. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated with broth macrodilution method. Data were analyzed with Mann-Whitney test. Minimum Inhibitory Concentration for Salvia officinalis and Pimpinella anisum for streptococcus mutans were respectively 6.25 and 12.5 µg/ml, for Lactobacillus rhamnosus were 1.56 and 12.5 µg/ml and for Actinomyces viscosus were 12.5 and 50 µg/ml.Both extracts had growth inhibitory effect on all three bacteria. Salvia officinalis had significantly greater effect on inhibition of growth of all three bacteria. Both extracts had bactericidal effect in the range of concentration.

Endodontic treatment of immature permanent teeth accompanies with several issues. The primary goal when treating such teeth is to maintain pulp vitality so that root development can occur normally. Indications and requirements for vital pulp therapy include asymptomatic and reversible pulpitis. Also there are controversial opinions regarding the ultimate clinical treatment of the vital pulp therapy techniques. In this manuscript we report 3 cases of immature symptomatic permanent molars with irreversible pulpitis caused by caries exposure of the pulp that have been undergone vital pulp therapy successfully.