Journal of Dental Medicine

Clinical and biometric evaluation of collagen membrane application for covering exposed root surfaces

A. Mieremadi

This study is aimed to evaluate the effect of covering exposed root surface by collagen membrane and to compare this method with coronoally advanced flap covering. 26 teeth in 20 patients (12m/8f) with Miller1 gingival recession were selected. 14 teeth were allocated into test group and 12 teeth in control group. Following first phase of treatment, clinical parameters including the height and width of gingival recession, attachment height, gingival crevice depth and keratinized tissue width were measured. In test group, coronally advanced flap was prepared and gingistat (as space maintainer) and collagen membrane was applied. For control group, coronally advanced flap method was applied without any further action. The measurements were done in 1,2 and 3 months post surgery. In test group, the reported root coverage was 71% while in control group was 57% which represents statistically significant difference. From first to third month post surgically, the average gingival recession in test group was 0.21 mm which was considered as creeping attachment phenomenon while in control group gingival height was increased 0.14 mm. the average width of recession and crevice depth decrease was not significantly different between the groups. On the other hand, The average attachment gain and keratinized tissue increase was significantly varied among the groups. In general, it can be concluded that application of collagen membrane as well as gingastat space maintainer can bring about satisfactory results in covering exposed root surfaces.

Evaluating stress distribution in two different designs of class I partial removable dentures

In Present study a digital model of hemimaxillectomy was reconstructed by computer and stress distribution of removable partial dentures in tissues, periodontal ligament and bone were thoroughly evaluated. The maximum stress of two different removable partial denture designs which contained buccal and lingual c-shaped clasps respectively were analyzed and compared. It was assumed that a 90 gram force which is equal to an average obturator’s weight is applied outwardly. The results showed that the maximum stress distribution in these two designs is not significantly different.

Comparing fluride release in conventional glass ionomer, light-cured glass ionomer and compomers

Current study is aimed to compare fluride release in conventional glass ionomer, light-cured glass ionomer and compomers. Standard samples from the aforementioned materials were prepared and measured by selective fluride ion electrode in intervals of 24hours, 1,2,3 and 4 weeks in neutral PH of 7 and acidic PH of 4.5. The obtained data represented that fluride ion release decreased in time but the pattern of this issue was different. Besides, it was found that in lower Ph fluride release is significantly affected. Compomer relatively releases less fluride than the others but as long as this amount can sufficiently prevent caries development, it can be stated that based on clinical status any of above choices can be selected. Besides, the more easily handled and available materials are used, the more successful the clinical results will be achieved.

Assessing in vitro tug-back effect on apical seal

There is lack of consensus among endodontic specialists about the necessity of tug back. In this regard, we designed a study in which 44 single rooted teeth with closed apex were selected and filed up to file #50. The teeth were obturated with lateral condensation method while in half of them there was not any tug back and in the other half tug back was achieved. Apical leakage was assessed by color infiltartion via microscope. The obtained results showed significantly lower infiltration in tug back group which leads to a direct relation between tug back and color infiltration although due to statistical analysis, this relationship was not reliable and needs further proofs.

Evaluating bond strength of porcelain to dental alloys and the effects of repeated porcelain sintering on it

In this study, porcelain bond strength to three different alloys of Gold-base, pd-Ag and base-Metal were compared and the effect of repeated porcelain sintering on bond strength was evaluated. The obtained results showed best bond strength of porcelain with Gold-base alloy. Pd-Ag and Base-metal alloys showed less strength respectively. During repeated sintering of porcelain, bond strength has not changed in Base-metal and Gold-base alloys while it was weakened in pd-Ag alloy.

Comparing high speed dental turbine and endoscopic device in crack formation following cavity preparation in periapical surgeries in Cat teeth

H. Razmi

In Present research study, 44 canine teeth of with completely formed apex was selected in 11 cats. Jaw bones were removed while teeth were kept intra alveolar sockets and routine root canal therapy was performed on each root. Afterwards, 3mm of each root were cut apically. 20 teeth underwent cavity preparation via high speed dental turbine and round diamond bur, 20 via endosonic device and 4 (10% of all) remained untreated as control group. Then, the cavity walls were assessed with stereomicroscope while the teeth were still kept in their alveolar sockets in order to detect cracks.

Comparing systolic and diastolic Blood pressure changes and heartbeat rate following administration of anesthetics containing epinephrine and felypressin

Complex mechanisms have been known for keeping blood pressure in normal level. In fact, these mechanisms have inter-related functions and can be dysregulated by both internal and external stimuli while cardiovascular system functions to minimize these changes. Vasoconstrictors can cause clinical and hemodynamical changes as 1-2 cartridges of epinephrine containing lidocaine can has no considerable effects in a normal individual ( unless administered IV) but 3 cartridges can bring about some clinical symptoms, according to a number of investigations. In current study, epinephrine’s effect on heartbeat rate was found more potent than felypressin which is considered as a disadvantage. on the other hand, epinephrine acts on arteries and can cause less bleeding, less drug toxicity and deeper and longer anesthesia. Therefore, it is preferred to felypressin due to its better action. It should be noted that the changes resulted by epinephrine and felypressin are of no significant importance in healthy individuals.

A two-year survey of facial bone fractures in patients referred to Mobasher Medical Center of Hamedan

MH. Ansari

This survey is aimed to retrospectively analyze the frequency rate of facial bone fractures based on sex, age, location, quality, risk factors and complications in order to assist medical practitioners and surgeons in improving educational and therapeutical plans and developing novel tools and methods. For this purpose, 274 patients with facial bone fractures were recruited through a two-year survey ( 1375-1376). The results revealed that car accidents ( 48.9%), fall from heights (27%) and street fights ( 20.4%) were the most important reasons leading to facial bone fractures. Among the study group, Men to women ratio was 3.3 to 1 and the average age was 25.8 years. 52.9% of fractures (most fractures) were happened in mandibular bone and the least prevalent fractures were reported in nasal bone ( 6.5%). The most critical pre or post-treatment complications associated with facial bone fractures were death (1%) and blindness (1%).