نشریه تحقیقات دندانپزشکی
سال سوم شماره 3 (پیاپی 5، پاییز 1393)

One of the most important considerations in cavity preparation is undesirable encroachment to pulpo, that is sometimes evident and  touchable by catheter accompanied with bleeding and in some cases, it  is clinically unable to be distinguished. The dentist's  awareness of the remaining dentin thickness as well as presence or absence of microscopic exposures in the cavity can assist in selecting an appropriate treatment. The aim of this study was to determine the incidence of  pulp microexposures in deep class V cavities in the human premolars.

In this descriptive study, 30 human premolar teeth were used scheduled for extraction due to orthodontic reasons. After signing the consent form, deep class V cavities were prepared on the buccal surface of each tooth for amalgam restoration. Then the teeth were extracted and the roots as well as lingual portion of the teeth were sectioned. The samples were immersed in 2% methylene blue solution, then the presence or absence of microscopic exposure was evaluated in the axial wall using light microscopy. Besides, the remaining dentine thickness  was measured by a digital caliper. The study data were analysed using SPSS  software (ver, 16) via  ANOVA and T-test.

Presence of microscopic exposure was confirmed in one tooth (3.2%), and the mean remaining dentin thickness in all samples was 0.67mm.

In 96.8% of deep class V cavities without clinical symptoms, about 0.67 mm of dentin remained, which may be regarded as a good criteria to predict remaining dentin thickness.

Diabetes is the most common metabolic disease, which can cause different lesions in the oral mucosa, among which Candidiasis can be mentioned as one of the most common types of these lesions especially in the uncontrolled diabetic patients. Therefore, the present study aimed to compare Candidia colony count in the saliva of controlled and uncontrolled diabetic patients.

This case control study was conducted on 40 controlled diabetic (HBA1C<7) and 40 uncontrolled diabetic (HBA1C>7) patients, who had the admission criteria for this study. Saliva samples were collected by spitting method and cultured on the special media to determine the colonization and Candida type in both groups. The study results were analyzed using T-test and spearman correlation tests.

The mean of Candida colony number was 54.2±85.3 in the controlled group and 186.3±192.9 in the un-controlled group, between which a statistically significant difference was observed (P=0.0001). Moreover, no significant correlation was reported between HBA1C and Candida colony number in both controlled and uncontrolled groups (P= 0.31 in controlled group, and P= 0.555 in un-controlled group). In this study, the Candida colony number separated from saliva samples of the controlled group and males (P=0.042) was significantly lower than the control group (P=000).

The mean of Candida colony number in saliva samples of uncontrolled diabetic patients was reported higher compared to the controlled group. There was no significant correlation between HBA1C levels and Candida colonization.

This study aimed to determine the effect of various scan delays, various Kilovotages and light storing conditions on the diagnostic accuracy of proximal caries detection in digital radiographic images obtained by the Photostimulable phosphor plates (PPP).

In this experimental and analytieal study, 45 non-cavitated permanent premolar and molar teeth with or without inter-proximal caries were radiographed using the DIGORA®PSP. The Plates were exposed at 60 (Kvp) and 70 (Kvp) and then were scanned immediately and 10 min, 30 min, 1, 6, 24 and 48h after the exposure. Within the exposure-to-scan priod, the plates were divided into two groups which the first group was stored in daylight and the second group was in a light-tight box. The diagnostic accuracy of caries was performed by scoring all the digital images. The true presence of caries was determined by dividing the teeth into two segments mesiodistally. The accuracy was reported as the area under Rock curve(Az). The Azs were compared using SPSS software (ver, 17) via two-way ANOVA and t-test. Moreover, Kappa was used to measure inter and intraobserver agreement.

The study results revealed no significant difference between immediately scanned Azs at 60 and 70 Kvp (P-value >0.05). The immediately scanned Az at 60Kvp was significantly higher than the Azs with 6h, 24h and 48h scan delays (P <0.05). Furthermore, the immediately scanned Az at 70Kvp was significantly higher than the Azs with 1, 6, 24 and 48h scan delays(P-value <0.05).

PSP scanning should not be delayed beyond 30 min in order to have an accurate proximal caries diagnosis. Longer delays may cause loss of quality of images.

Although Chlorhexidine mouthwash involves the most effective antiseptic in order to control the plaque as well as to prevent gingivitis, the incidence of some side effects has made an obstacle to use this substance permanently. Persica herbal mouthwash has recently been introduced to Iran’s market demonstrating no side effects of chemical substances consumption. Therefore, this study aimed to compare the effects of two Persica and Chlorhexidine mouthwashes on gingiva bleeding after scaling in order to determine an appropriate mouthwash to improve gingival bleeding after the priodental treatment.

In this clinical trial, 39 patients participated referring to periodontics department of Yazd dentistry school who had slight to moderate gingival inflammation and were randomly classified into three groups by parallel and double blind research design. Normal saline was given to the first group, chlorhexidine 0.2% was provided to the second group and persica was presented to the third group. The gingival bleeding index was evaluated at the beginning of study, precisely immediately and one week after mouthwash use. The collected data were analyzed by SPSS software (ver. 18) via Kruskal-Willis, Mann-Whitney, Wilcoxon and Chi-square tests.

The study results demonstrated the higher effect of persica on lowering gingival bleeding index compared to chlorhexidine which this difference proved to be statistically significant (p<0.05).

Using persica mouthwash can lead to a significant decrease in gingival bleeding. The study findings revealed that it seems persica mouthwash can be utilized in treatments of gingival diseases.

The cranial base plays an important role in craniofacial growth. Since the maxilla is connected with the anterior part of the cranial base and the mandible rotation is influenced by the maxilla, a possible relationship may exist between the cranial base morphometric indices and sagittal jaw malposition. Therefore, the present study aimed to measure cranial base morphometric indices in the patients referred to Shahid Sadoughi faculty of dentistry.

In this descriptive cross-sectional study, 90 files of patients referring to orthodontic department of Shahid Sadoughi Dentistry School were selected which were divided into skeletal classІ (n=30), class П (n=30), class Ш (n=30). The anterior and posterior cranial base lengths (SN,SBa) and the cranial base angles (NSBa, NSAr) were measured. The SPSS software (ver, 16) was applied utilizing mann-whitney test in order to compare the indices between the three groups.

The difference between the NSBa,NSAr mean was statistically significant in three groups, though the anterior and posterior cranial base lengths (SN,SBa) did not show any significant differences.

The study findings demonstrated that the saddle angle (NSAr) was highly related to sagittal malposition of the jaw.

Debonding of artificial teeth from denture base resin is regarded as a considerable problem for the patients who wear dentures. Utilizing multilithic teeth has not yet managed to solve this problem. Hence, this study aimed to compare the various surface treatments of multilithic teeth to denture base resin.

In this experimental laboratory study, 44 maxillary first molar were used,whichwere divided intofour groups(n=11): control, control + MMA, sandblast, and sandblast + MMA. After resin packing and polymerization, each of specimens was tested by universal testing machine with cross head speed of 1 mm/min. The study data were analyzed by one-way ANOVA and supplementary Post HocTukey
tests (P<0.05).

The mean bond strength in control + MMA (342.09±45.32 Newton) group was reported higher than the other groups, followed by sandblast + MMA (222.09±32.15 Newton), sandblast (177.36±24.78 Newton) and control (104.45±21.07 Newton) groups, between which a significant difference was observed (P<0.05). Adhesive failure was observed as the most common fracture mode, specifically in the control and sandblast groups.
Conclusion

The study findings revealed thatchemical treating of the ridge lap surface of multilithic teeth by methyl methacrylate monomer significantly improved bond strength to denture base resin compared to the mechanical surface treatment.

Exfoliative cheilitis is an inflammatory condition characterized by regular peeling of keratin superficial layer. The unpleasant appearance and dryness of lips in this condition could be mentioned as the cause of complaint and discontent in patients. Therefore, this study aimed to compare the therapeutic effects of Vaseline and sterile ophthalmic vitamin A ointment on treatment of Exfoliative cheilitis.

In this double-blind clinical trial, 30 patients with Exfoliative cheilitis were identified, who were randomly divided into two groups: Vitamin A and Vaseline. The patients recieved the drugs topically, 3 times per day for 1 week as directed. Improvement in both groups, including severity and size of lesions, were measured on 2nd, 4th and 7th days, and the study data were analyzed applying Mann-Whitney test at significance level of 0.05.

The mean and SDs of the lesions size did not reveal any statistically significant differences  before and after treatment (P-value >0.05). The mean and SDs of lesions severity were proved to be significant in each group after the treatment in comparison with before the treatment (P-value< 0.001), though no significant differences were reported comparing the two groups, except the 4th day, that vit A demonstrated more improvement compared to Vaseline.

The study findings revealed that both vit A oinment and Vaseline are both effective in improving lesion severity of Exfoliative cheilitis, although vit A oinment is more effective in improving its signs and symptoms.

Peripheral Giant Cell Granuloma (PGCG) is recognized as a reactive lesion in oral cavity which demonstrates a marked gender predilection with more prevalence within females suggesting a possible role for steroid hormones (estrogen and progesterone) in pathogenesis, development and progression of the lesions. Therefore, this study aimed to the investigate the existence and distribution of estrogen and progesterone receptors in PGCG of the oral cavity.

In this case control study, Hematoxylin and Eosin (H&E) and Immunohistochemical staining were performed on 10 PGCG paraffin blocks and 10 samples of normal gingival mucosa using estrogen and progesterone antibodies. The percentage of positive cells was determined using scaled eyepiece. The study data were then analyzed via SPSS software (ver.15) using Chi- square test.

In 10 cases of PGCG, estrogen and progesterone receptors demonstrated negative staining in osteoclastic giant cells, stromal cells, blood vessels, endothelial cells and oral mucosal epithelium. The staining for all samples of normal gingival mucosa was reported to be negative, as well (P value PR=0.220,
P value ER=1.250).

The findings of this study revealed no expression of estrogen and progesterone receptors in oral cavity PGCG. As a result, other factors expect for sexual hormones may be effective in progression and development of this lesion.