Journal of Dental School
Volume:39 Issue: 2, Spring 2021

Ideal implant placement decreases the postoperative surgical, prosthetic, and functional complications. This study aimed to design and fabricate a surgical guide for accurate positioning and angulation of dental implants in edentulous mandibular models and assess its efficacy.

After initial designing and fabrication of resin model of the surgical guide and eliminating its shortcomings, the final model was fabricated using 6061t6 aluminum alloy by a computer numerical control machine. The efficacy of the designed surgical guide was tested by placing 16 implants with the help of the surgical guide in two completely edentulousmandibular models. Next, cone-beam computed tomography DICOM images were obtained from the inserted dental implants, and analyzed by NNT Viewer software. One-sample t-test was applied to compare deviations of implant angle and distance from the planned angulation/position at P<0.05 level of significance.

The mean angular deviation between the planned and placed implants was 3.31±1.2° and 0.97±0.56° for 0° and 15° implants, respectively. The mean linear deviation between the planned and placed implants was 1.00±0.75 mm. Although the linear and angular differences between the planned and placed implants were statistically significant (P<0.05), they were clinically acceptable.

The designed surgical guide showed the expected efficacy with maximum mesiodistal angular deviation < 5° and linear deviation < 1 mm in 56% and < 1.5 mm in 75% of the placed implants, compared with the planned angulations/positions.

The proportion of older people is increasing faster than other age groups. Evidence shows that older people receive less oral health services than what they need. The purpose of this study was to investigate the barriers against the provision of oral healthcare services to the elderly from the perspective of dentists and managers of elderly care centers (ECCs) in Tehran.

This qualitative study was conducted using semi-structured interviews. The study population included managers of ECCs and dentists who work in the field of geriatric dentistry in Tehran. Participants were selected by purposive and convenience sampling. Interviews were continued until saturation of the information in both groups. The interviews included about 10 predetermined questions regarding different aspects of providing dental care services to the elderly. The Graneheim and Lundman’s qualitative approach was used for content analysis of the interviews.

The data reached saturation after conducting interviews with nine managers of the ECCs and seven dentists. Finally, five main themes were extracted by the content analysis including "problems related to accessing care", "problems related to disability", "financial problems", "problems related to dentists" and "problems related to policy-making”.

Several barriers exist related to service recipients, service providers, and policy-makers against the provision of oral healthcare services to the elderly. Removing these barriers requires cooperation between the education, health, and treatmentsectors of the Ministry of Health, the Welfare Organization, and professional dental organizations.

This study aimed to evaluate the effect of labiopalatalinclination of maxillary right central incisor on palatal bone width using cone-beam computed tomography (CBCT).

The angle formed between the longitudinal axis of the right central incisor and the palatal plane was measured on 75 CBCT images, andclassified into three groups of labially-inclined, lingually-inclined, and normal groups. The total palatal bone thickness in the apical region of the upper right central incisor was linearly measured perpendicular to the tooth axis on sagittal slices. The intraclass correlation coefficient, Kolmogorov-Smirnov test, one-way ANOVA, and Pearson’s and Spearman’s correlation coefficients were used for data analysis (alpha=0.05).

A significant difference was noted among the groups in the total apical palatal bone thickness (P<0.05). The labially-inclined group had significantly lower bone thickness than the other two groups (P=0.002, 95% CI: 5.5-7.38); however, this correlation wasinverse (Pearson’s R=-0.58), which means that as the angle between the upper central incisor axis and the palatal plane increased, the bone thickness significantly decreased. No correlation was found between the palatal bone thickness (cancellous or cortical) and tooth inclination (P>0.05). Arch length was not correlated with any group either (P>0.05).

Labial inclination of upper central incisor causes the root apex to be closer to the palatal alveolar bone, resulting in lessapical bone supportin the palatal area

This study investigated the prevalence and pattern of lip premalignant lesions in patients referred to the Cancer Institute of Imam Khomeini and Shohada-E-Tajrish Hospitals between 2004 and 2016.

This retrospective cross-sectional study was conducted on the pathology reports of patients retrieved from the archives of the Pathology Departments of the Cancer Institute of Imam Khomeini and Shohada-E-Tajrish Hospitals between 2004 and 2016. The gender, age, lesion location (upper lip, lower lip, commissure, lip in general, not stated), pathological type, and clinical diagnosis of the lesions were extracted from patient records. The Fisher's Exact test was used to analyze the data by SPSS version 16.

Of a total of 237,392 patients, 40 (0.02%) cases had lip premalignant lesions. The mean age of patients was 63.71±14.11 years (range 3 to 92 years). The prevalence of lip premalignant lesions was higher in males, with a male to female ratio of 4:1. The most common location and histopathological type of lesions were the lower lip, and actinic keratosis (60% of the cases), respectively.

Lip premalignant lesions were observed in 0.02% of patients. Although this rate is lower than the global prevalence of precancerous lesions of the lip and oral cavity (4.47%), because of the high malignant transformation rate of lip premalignant lesions, every clinician must take part in early detection of these lesions by clinical examination. To confirm the diagnosis, biopsy may be requested for histopathological diagnosis.

Surfaces commonly touched during dental procedures can serve as a reservoir of microorganisms and lead to cross-infection. The aim of the present study was to assess the microbial contamination of tray, light handle and dental chair handles before and after disinfection with Deconex (Solarsept).

Samples were randomly collected from the tray, light handle and dental chair handles of active dental units in the Periodontics, Prosthodontics and Oral and Maxillofacial Surgery Departments of Dental School of Shahid Beheshti University of Medical Sciences. The samples were collected at two time points before and after daily surface disinfection with Deconex. Thecollected samples were sent to a microbiology laboratory to determine the type and number of microorganisms. Data were analyzed by Wilcoxon signed rank test (α=0.05).

Based on the culture results and according to microscopic examination and Gram staining, the highest level of bacterial contamination before disinfection with Deconex (Solarsept) was found on dental units of the Oral and Maxillofacial Surgery Department (handles and tray), with Gram-positive Bacillus spp. Fixed and removable prosthodontics departments did not have any bacterial contamination. Overall, a reduction in bacterial load was detected after Deconex decontamination (P=0.05).

Spraying and wiping of dental unit components with Deconex at the end of working hours decreased the bacterial growth, and this effect remained until the next working day.

Considering the significance of early detection of caries and determining the extent of carious lesions for appropriate treatment planning, as well as introduction of new diagnostic tools, this study aimed to compare VistaCam iX (850 nm infrared), and DIAGNOdent (655 nm) for detection of proximal caries in posterior teeth.

This in vitro study was performed on 40 extracted sound posterior teeth. VistaCam and DIAGNOdent examinations were performed. The teeth were sectioned for histopathological examination under a stereomicroscope to determine the presence/absence of caries and extent of carious lesion, if any (to serve as the gold-standard). Data were analyzed with the Cohen’s kappa statistic, and Wilcoxon Rank Sum test.

The specificity of VistaCam iX and DIAGNOdent was 71.4% and 42.8%, respectively. Their sensitivity was 100% and 40% for enamel caries, and 92.8% and 53.5% for dentin caries, respectively (P=0.048). The specificity and sensitivity of DIAGNOdent were higher, and it had lower rate of false positive and false negative results.

Considering the higher sensitivity and significantly lower rate of false negative results of VistaCam iX for detection of proximal caries, it may be recommended as an efficient tool for caries detection

Guided bone regeneration (GBR) is one of the most commonly used techniques for alveolar ridge augmentation. With the increasing demand for implant treatments and ridge augmentation, the prevalence of GBR complications has also increased. Herein, we discuss the factors affecting particulate graft integration in the GBR technique, and describe re-treatment of a failed site.

GBR with particulate xenograft bone material was performed in a systemically healthy young female. After 6 months, the re-entry surgery revealed failed graft integration despite the clinically normal appearance of the site, and uneventful healing period. The failed site was re-treated successfully with cortical tenting technique, and re-entry revealed integrated graft after 5 months from the second surgery.

In addition to the PASS principle to achieve successful results in GBR, the graft particle properties, compaction force of the graft particles, defect characteristics, and waiting time for graft maturation are some of the factors that may affect the results of GBR. Cortical tenting could be a predictable technique for subsequent grafting in failed GBR sites.