Assessment of CBCT gray value in different regions-of-interest and fields-of-view compared to Hounsfield unit.

OBJECTIVES: Different factors can affect the discrepancy between the gray value (GV) measurements obtained from CBCT and the Hounsfield unit (HU) derived from multidetector CT (MDCT), which is considered the gold-standard density scale. This study aimed to explore the impact of region of interest (ROI) location and field of view (FOV) size on the difference between these two scales as a potential source of error. METHODS: Three phantoms, each consisting of a water-filled plastic bin containing a dry dentate human skull, were prepared. CBCT scans were conducted using the NewTom VGi evo system, while MDCT scans were performed using Philips system. Three different FOV sizes (8 × 8 cm, 8 × 12 cm, and 12 × 15 cm) were used, and the GVs obtained from eight distinct ROIs were compared with the HUs from the MDCT scans. The ROIs included dental and bony regions within the anterior and posterior areas of both jaws. Statistical analyses were performed using SPSS v. 26. RESULTS: The GVs derived from CBCT images were significantly influenced by both ROI location and FOV size (p < 0.05 for both factors). Following the comparison between GVs and HUs, the anterior mandibular bone ROI represented the minimum error, while the posterior mandibular teeth exhibited the maximum error. Moreover, the 8 × 8 cm and 12 × 15 cm FOVs resulted in the lowest and highest degrees of GV error, respectively. CONCLUSIONS: The ROI location and the FOV size can significantly affect the GVs obtained from CBCT images. It is not recommended to use the GV scale within the posterior mandibular teeth region due to the potential for error. Additionally, selecting smaller FOV sizes, such as 8 × 8 cm, can provide GVs closer to the gold-standard numbers.

Evaluation of matrix metalloproteinase-1, -2, -3, -7, and -13 gene polymorphisms in patients with chronic periodontitis and healthy controls.

OBJECTIVES: The current study aimed to investigate the association of matrix metalloproteinase- (MMP-) 1, -2, -3, -7, and -13 gene polymorphisms with chronic periodontitis (CP) in an Iranian population. MATERIALS AND METHODS: In this case-control study, 87 subjects with CP and 89 periodontally healthy subjects were allocated to case and control groups, respectively. Subjects' venous blood samples (5 cc) were collected, and DNA extraction was performed. A spectrophotometer was utilized to assess the concentration of extracted DNAs. The desired gene polymorphisms were examined using restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) followed by electrophoresis. Statistical analyses were done using the Pearson Chi-Square test, odds ratio, and t-Test using SPSS Version 28. RESULTS: The MMP-1 (-1607 1G/2G) rs1799750, MMP-3 (-1171 5A/6A) rs3025058, and MMP-7 (-181 A/G) rs11568818 gene polymorphisms significantly differed between case and control groups (PV = 0.019, 0.007, and 0.028, respectively). In contrast, the gene polymorphisms of MMP-2 (-1306 C/T) rs243865 and MMP-13 (-77 A/G) rs2252070 did not make a significant difference. Regarding allele frequencies, the presence of the 2G allele in the MMP-1 (-1607) rs1799750 genotype increased the CP susceptibility significantly, while subjects with the 6A allele in their MMP-3 (-1171) rs3025058 genotype showed significantly lower susceptibility to CP (PV = 0.008 and < 0.001, respectively). CONCLUSION: In the studied population, gene polymorphisms in the DNA sequences of MMP-1 (-1607 1G/2G) rs1799750, MMP-3 (-1171 5A/6A) rs3025058, and MMP-7 (-181 A/G) rs11568818 may have impacts on CP incidence. CLINICAL RELEVANCE: Clinicians should be cautious about the association between MMP-1, MMP-3, and MMP-7 gene polymorphisms and the incidence of chronic periodontitis during periodontal treatment planning.

Photodynamic Therapy in Root Canal Disinfection: A Case Series and Mini-Review.

Introduction: Photodynamic therapy (PDT) is now a widely used treatment modality in many fields of dentistry, including endodontics. The most common application of PDT in endodontics is to disinfect root canals. The purpose of this study was to present the experience of using PDT in root canal disinfection of three patients. Case Presentation: Three patients referred to the Endodontics Department of Shahid Beheshti University of Medical Sciences were treated using 0.1 mg/mL Toluidine Blue (FotoSan® agent; CMS Dental, Denmark) irradiated with a light-emitting diode (LED) lamp (FotoSan®; CMS Dental, Denmark) with a mean wavelength of 630 nm and a mean power density of 3 W/cm2 over two 30-second periods. Conclusion: PDT using LED lighting can be used in conjunction with conventional root canal treatment (RCT) to achieve great results.

Estimating and comparing the duration of adolescent growth peak in skeletal class I and III subjects using cervical vertebral maturation method.

BACKGROUND: Estimating skeletal maturation and growth potential is essential for developing adolescents' best orthodontic treatment plan. The purpose of this study was to compare the duration of adolescent growth peak in subjects of skeletal classes I and III using the cervical vertebral maturation (CVM) method. METHODS: This retrospective cross-sectional study included 116 Iranian subjects (skeletal class I = 68, skeletal class III = 48) aged 8-16 years old and without previous orthodontic treatments. Using Steiner and Wits analyses, two independent examiners traced pre-treatment lateral cephalograms to determine the subjects' skeletal relationship. The skeletal maturation was then assessed using Baccetti's CVM method. The onset and duration of adolescent growth peak (interval of CS3-CS4) were compared between two skeletal classes and two genders using independent samples t test. RESULTS: In skeletal class I and III subjects, the adolescent peak had a mean duration of 1.62 (± 1.33) and 2.00 (± 1.27) years, respectively. The average difference of 0.38 years (4.6 months) between the two groups was statistically significant (p < 0.001). Furthermore, the onset age of adolescent growth peak was 11.91 (± 1.32) and 12.08 (± 1.31) years old in class I and III subjects, respectively. This age difference was not statistically significant (p = 0.630). Males' adolescent growth peak occurred 1.44 years later (p < 0.001) and lasted 0.20 years less (p < 0.001). CONCLUSIONS: The adolescent growth peak started at a similar age in class I and III subjects, but the latter experienced the peak for 4.6 months longer. Moreover, females had an earlier and more extended adolescent growth peak.

Gingival Melanin Depigmentation Using a Diode 808-nm Laser: A Case Series.

Introduction: Gingival hyperpigmentation is caused by an increase in the amount of melanin production or the number of melanocytes in the epithelium, which can impair smile esthetics. The current study aimed to report the experience of using a diode laser for gingival depigmentation of three different patients. Case Presentation: Three adult patients are presented with hyperpigmentation in labial gingivae of both jaws. The depigmentation was done using a diode laser at a wavelength of 808 nm, fiber diameter of 300 µm, and power of 1 W and in continuous mode. All three patients showed proper resolution of hyperpigmented areas in short- and long-term follow-up sessions. However, degrees of recurrence were noticeable in two cases. Conclusion: The 808-nm diode laser can be utilized safely and efficiently in gingival depigmentation, resulting in an acceptable cosmetic outcome.