Investigation of the best effective fold of data augmentation for training deep learning models for recognition of contiguity between mandibular third molar and inferior alveolar canal on panoramic radiographs.

OBJECTIVES: This study aimed to train deep learning models for recognition of contiguity between the mandibular third molar (M3M) and inferior alveolar canal using panoramic radiographs and to investigate the best effective fold of data augmentation. MATERIALS AND METHODS: The total of 1800 M3M cropped images were classified evenly into contact and no-contact. The contact group was confirmed with CBCT images. The models were trained from three pretrained models: AlexNet, VGG-16, and GoogLeNet. Each pretrained model was trained with the original cropped panoramic radiographs. Then the training images were increased fivefold, tenfold, 15-fold, and 20-fold using data augmentation to train additional models. The area under the receiver operating characteristic curve (AUC) of the 15 models were evaluated. RESULTS: All models recognized contiguity with AUC from 0.951 to 0.996. Ten-fold augmentation showed the highest AUC in all pretrained models; however, no significant difference with other folds were found. VGG-16 showed the best performance among pretrained models trained at the same fold of augmentation. Data augmentation provided statistically significant improvement in performance of AlexNet and GoogLeNet models, while VGG-16 remained unchanged. CONCLUSIONS: Based on our images, all models performed efficiently with high AUC, particularly VGG-16. Ten-fold augmentation showed the highest AUC by all pretrained models. VGG-16 showed promising potential when training with only original images. CLINICAL RELEVANCE: Ten-fold augmentation may help improve deep learning models' performances. The variety of original data and the accuracy of labels are essential to train a high-performance model.

Application of a Multi-Layer Perceptron in Preoperative Screening for Orthognathic Surgery.

OBJECTIVES: Orthognathic surgery is used to treat moderate to severe occlusal discrepancies. Examinations and measurements for preoperative screening are essential procedures. A careful analysis is needed to decide whether cases require orthognathic surgery. This study developed screening software using a multi-layer perceptron to determine whether orthognathic surgery is required. METHODS: In total, 538 digital lateral cephalometric radiographs were retrospectively collected from a hospital data system. The input data consisted of seven cephalometric variables. All cephalograms were analyzed by the Detectron2 detection and segmentation algorithms. A keypoint region-based convolutional neural network (R-CNN) was used for object detection, and an artificial neural network (ANN) was used for classification. This novel neural network decision support system was created and validated using Keras software. The output data are shown as a number from 0 to 1, with cases requiring orthognathic surgery being indicated by a number approaching 1. RESULTS: The screening software demonstrated a diagnostic agreement of 96.3% with specialists regarding the requirement for orthognathic surgery. A confusion matrix showed that only 2 out of 54 cases were misdiagnosed (accuracy = 0.963, sensitivity = 1, precision = 0.93, F-value = 0.963, area under the curve = 0.96). CONCLUSIONS: Orthognathic surgery screening with a keypoint R-CNN for object detection and an ANN for classification showed 96.3% diagnostic agreement in this study.

Enhanced effectiveness of silver diamine fluoride application with light curing on natural dentin carious lesions: an in vitro study.

This study aimed to compare the mean mineral density difference (mMDD) and surface morphology of 10- and 60-s silver diamine fluoride (SDF)-applied dentin carious lesions and to study the effect of an additional 20-s light curing (LC) on SDF-treated teeth. Forty primary molar blocks with natural dentin carious lesions were measured for baseline lesion depth and mineral density using Image-Pro Plus software. The samples were randomly distributed into 4 groups; 38% SDF applied for 1) 10-s (10SDF), 2) 60-s (60SDF), 3) 10-s + LC (10SDF + LC), 4) 60-s + LC (60SDF + LC) and an additional control group to assess the outcome of pH-cycling only. Then all the groups underwent a 7-d bacterial pH-cycling. The dentin carious lesions' mMDD was determined by digital subtraction radiographic analysis. The surface morphology and elemental profile were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mMDD of the dentin lesions was analyzed using two-way ANOVA, generalized linear models analysis. Light curing was the only factor that affected the mMDD (p = 0.007). The mMDD in the 10SDF + LC and 60SDF + LC groups were significantly higher than those without light curing (p = 0.041 and 0.041, respectively). The 60SDF + LC group demonstrated a significantly higher mMDD than the 10SDF group (p = 0.010), while that in the 10SDF + LC group was similar to the 60SDF group (p = 1.00). Scanning electron microscopy revealed denser mineral content layers, which were likely silver and chloride, in the 10SDF + LC and 60SDF + LC groups than in the 10SDF and 60SDF groups, respectively. In conclusion, shortened application time with light curing enhanced SDF remineralization similarly to the conventional method.

Patient-reported outcome measures (PROMs) comparing digital and conventional workflows for treatment with posterior single-unit implant restorations: A randomized controlled trial.

OBJECTIVES: The aim of this randomized controlled trial (RCT) was to analyze patient-reported outcome measures (PROMs) of prosthetic therapy with monolithic implant crowns in completely digital workflows (test) with intraoral optical scanning (IOS) and conventional workflows (control) with conventional impressions. Secondary, an objective evaluation of the final implant restorations was performed using the Functional Implant Prosthodontic Score (FIPS). MATERIALS AND METHODS: Forty patients who required an implant-supported single crown on posterior regions were randomly divided into test (n = 20) and control (n = 20) groups for impression taking. Each group was then equally separated into two subgroups according to the restorative material used: lithium disilicate (LS2, N!CE®, Straumann AG, Basel, Switzerland) or polymer-infiltrated ceramic networks (PICN, Enamic®, Vita, Bad Säckingen, Germany). Patient satisfaction was evaluated using PROM questionnaires with visual analog scales (VAS) after impression-taking and 1 week after prosthetic delivery. Patient satisfaction with the impression technique was assessed in six domains: length, comfort, anxiety, taste, nausea, and pain, whereas patient satisfaction with the final restoration was assessed in four domains: overall treatment outcome, functionality, esthetics, and cleanability. In addition, the final implant restorations were objectively assessed by an independent prosthodontist using the FIPS. Mann-Whitney U test was used to analyze the defined outcomes. Statistical analysis was completed with a level of significance set at α=0.05. RESULTS: PROMs focusing on the impression technique demonstrated higher levels of patient satisfaction for IOS compared to conventional impressions, especially in terms of "taste irritation" (p = 0.036); whereas no significant differences were found between both restorative CAD/CAM-materials. Mean FIPS values demonstrated similar results among subgroups. CONCLUSIONS: Within the limitation of this study, both completely digital and conventional protocols provided great levels of patient satisfaction in implant rehabilitation of single-tooth gaps in posterior sites with monolithic implant crowns. The restorative material, LS2 versus PICN, does not impact patient satisfaction with their treatment. However, a long-term follow up is needed to draw more specific conclusions on patient satisfaction with the restorations.

Patient-reported outcome measures comparing static computer-aided implant surgery and conventional implant surgery for single-tooth replacement: A randomized controlled trial.

OBJECTIVE: To compare static computer-aided implant surgery (s-CAIS) and conventional implant surgery (CIS) for single-tooth replacement in posterior sites in terms of patient-reported outcome measures (PROMs). METHODS: Forty patients were divided into two groups for treatment with s-CAIS (Test) and CIS (Control). Patients' anxiety level was measured using the modified dental anxiety score before implant surgery. After surgery, patients completed two questionnaires for 7 days. The first questionnaire assessed pain level using a visual analog scale (VAS) and the incident rate of pain using a 5-point Likert scale; analgesic intake was also recorded. The second questionnaire investigated patients' oral health-related quality of life (OHRQoL) including postoperative symptoms, oral function, and daily activity. The difference between data was compared at significance level (α = 0.05). RESULTS: There was no statistically significant difference in pretreatment dental anxiety level, postoperative pain scores, and OHRQoL between treatment groups. Overall, mild or moderate dental anxiety was reported by 70% and 20% of patients, respectively. Pain score was significantly reduced by postoperative Day 3 in the test group and Day 4 in the control group, compared with baseline. Both groups significant reduced analgesic intake by postoperative Day 5. Most OHRQoL-related complaints subsided approximately 3 days after surgery. CONCLUSIONS: Overall, PROMs between s-CAIS and CIS were not significantly different for the single-tooth implant surgery in the posterior area. Postoperative symptoms after implant surgery still inevitably occurred, reflecting the normal process of oral wound healing.

Different Implant Subgingival Depth Affects the Trueness and Precision of the 3D Dental Implant Position: A Comparative in Vitro Study Among Five Digital Scanners and a Conventional Technique.

PURPOSE: The aim of this study was to investigate the effect of implant subgingival depth on the trueness and precision of the 3D implant position, and the effect of digital implant impression techniques on the 3D implant position. MATERIALS AND METHODS: Three resin master models were created with implant analogs submerged 3, 6, and 9 mm from the gingival margin. Four intraoral scanners (TRIOS, DWIO, Omnicam, and TruDef), one laboratory scanner (E3), and a conventional impression technique were used to take impressions of the master models, which resulted in six test models for each depth. These six impression techniques were performed six times for precision assessment. The master models were sent for high-powered micro-focused computed tomography as the gold standard control group. The scan body positions of the test models and their control models were superimposed using reverse-engineering software. The 3D distortion of the implant position in each comparison was measured by linear distortion (dx, dy, dz) and calculated as the global linear distortion (dR). RESULTS: The trueness of the mean dR values at the 3-mm, 6-mm, and 9-mm implant depths was 99 µm, 60.6 µm, and 107 µm, respectively. The least significant difference test of the impression system showed that all the digital impression techniques except the DWIO scanner had better trueness than the conventional impression technique. The 6-mm implant depth exhibited a significantly lower 3D distortion of the implant position than those of the 3-mm and 9-mm implant depths. The E3 scanner had the highest precision, while the conventional impression technique had the lowest precision. All the intraoral scanners except the DWIO scanner showed better precision than the conventional impression technique. CONCLUSION: Most of the intraoral scanners had better trueness and precision than the conventional impression technique for up to 6 mm of implant subgingival depth.

Odontogenic keratocyst and ameloblastoma: radiographic evaluation.

OBJECTIVES: To describe the radiographic features of odontogenic keratocysts (OKCs) and ameloblastomas and to compare the radiographic findings between these 2 lesions. METHODS: Radiographs of OKCs and ameloblastomas were retrospectively reviewed. Location, border, shape, association with impacted tooth, tooth displacement, root resorption, and bone expansion were evaluated. Chi-squared or Fisher's exact tests were used for statistical analysis. A p value < 0.05 was considered to indicate statistical significance. RESULTS: One hundred OKCs and 101 ameloblastomas were reviewed. The ratios of maxilla to mandible were 1:1.4 and 1:9.1 in OKCs and ameloblastomas, respectively. All evaluated features significantly differed between OKCs and ameloblastomas (p ≤ 0.001). Most OKCs showed smooth border (60%) and unilocular shape (82%), while most ameloblastomas showed scalloped border (77.2%) and multilocular shape (68.3%). Association with impacted tooth was found in 47% of OKCs and 18.8% of ameloblastomas. Adjacent tooth displacement was found in 33.7% of OKCs and 55.8% of ameloblastomas. Root resorption was more common in ameloblastomas (66.7%) than in OKCs (7%). Bone expansion was also more common in ameloblastomas (96.3%) than in OKCs (63.6%). CONCLUSION: A unilocular radiolucent lesion with smooth border, no adjacent tooth displacement, no root resorption and causing mild or no bone expansion is suggestive of an OKC rather than an ameloblastoma.

Prevalence and morphometric analysis of the alveolar antral artery in a group of Thai population by cone beam computed tomography.

OBJECTIVE: To investigate the prevalence, diameter, and position of the alveolar antral artery (AAA) canals and measure the distances from the canal to the maxillary sinus floor and to the edentulous alveolar crest in each posterior maxillary tooth locations by cone beam computed tomography (CBCT). METHODS: CBCT images of the posterior maxillary region from 280 patients were investigated. The prevalence and diameter of the AAA canal were evaluated. The perpendicular distances from the canal to the maxillary sinus floor and to the edentulous alveolar crest of each tooth locations were measured. The mediolateral positions and routes of the canals were observed with novel classification. Statistical analyses were carried out to determine any significant differences in mean distances between the tooth locations along with mean distances of tooth location by age, gender, and dentate status. RESULTS: The AAA canal was found in 94.6% with a mean diameter ± SD of 1.05 ± 0.34 mm. The mean ± SD perpendicular distance from AAA canal to the edentulous alveolar crest at the first (16.02 ± 3.94 mm) and the second molars (16.74 ± 3.51 mm) were significantly shorter than the second premolar region. The intrasinus mediolateral position of the canal (72.5%) was the most common in concordance with the all-in type mediolateral route (50.9%). CONCLUSION: The intrasinus mediolateral position of the AAA canal is a common structure in the lateral wall of maxillary sinus, which could be detected with CBCT images. The all-in type is the most prevalent mediolateral route among a novel 7-type classification system of AAA routes. Owing to the short distance between the AAA canal and the alveolar crest in the first and second molar locations, CBCT images should be taken to investigate the AAA position and route before sinus lift procedure to prevent the risk of hemorrhage.

Increased Plasma Osteocalcin, Oral Disease, and Altered Mandibular Bone Density in Postmenopausal Women.

An association between oral diseases and postmenopausal status has been recognized. However, the relationship between all oral disease, mandibular bone density, health status, and osteocalcin (OCN) bone markers in postmenopausal dental patients has not been reported. This study was therefore to verify the differences in plasma OCN levels, dental, periodontal, and oral mucosal disease, and mandibular bone density alterations from panoramic radiograph and systemic parameters in postmenopausal women, compared to premenopausal women. Oral, radiographic, and blood examination were performed in 92 females. Dental, periodontal, and oral mucosal statuses were recorded. Health profile parameters were collected from medical charts. Plasma OCN was evaluated by enzyme-linked immunosorbent assay. Forty-two (45.7%) participants were postmenopausal with a higher median age (55 (51, 62) years) than the premenopausal group (43 (38, 45) years). Overweight or obesity, hypercholesterolemia, and impaired fasting blood sugar were more prevalent in postmenopause. The average postmenopausal OCN level (425.62 ng/mL) was significantly higher than the premenopausal group (234.77 ng/mL, p < 0.001). The average number of missing teeth, mean attachment loss, alveolar bone loss, periapical lesion count, and clinical oral dryness score were also significantly higher in postmenopause (p=0.008, < 0.001, 0.031, 0.006, and 0.005, respectively). However, mandibular bone density determined by mandibular cortical index was lower in postmenopause (p < 0.001). The panoramic mandibular index, mandibular cortical width, fractal dimension, and other oral mucosal disease did not differ between the groups. Postmenopause was associated with elevated plasma OCN (ß = 0.504, p < 0.001) when related covariates were adjusted. Elevated plasma OCN, oral mucosal dryness, high number of periapical radiolucencies and missing teeth, and lower mandibular bone density from panoramic radiograph were prevalent in postmenopausal women. Dentists should suspect an increased risk of low bone mineral density in postmenopausal patients who display these clinical and radiographic findings, and they should be referred for further examination. Plasma OCN may interconnect a relationship between postmenopausal status and the low mandibular bone density.

Correlation of plasma osteopontin and osteocalcin with lower renal function in dental patients with carotid artery calcification and tooth loss.

OBJECTIVES: To investigate plasma osteopontin (OPN) and osteocalcin (OCN) levels in dental patients with carotid artery calcification (CAC) and determine the correlations between these proteins and renal function and tooth loss. METHODS: The health parameters and number of teeth of 99 participants were recorded. Panoramic radiographs were taken for CAC evaluation, and OPN and OCN levels were measured. RESULTS: None of the participants had overt kidney disease, and 14 (14.14%) had CAC. The age, sex, and health profiles of patients with CAC were not different from those without CAC. The OPN and OCN levels in participants with CAC were higher than in those without (p = 0.026 and p = 0.025, respectively). The OPN levels were correlated with the estimated glomerular filtration rate (eGFR) (p = 0.021) and tooth loss (p = 0.027). The OCN levels were correlated with the eGFR (p = 0.002), tooth loss (p = 0.023), blood urea nitrogen (p = 0.040), and creatinine levels (p = 0.031). The median tooth loss in individuals with an eGFR <60 mL/min/1.73 m2 was higher than that of individuals with an eGFR ≥60 mL/min/1.73 m2 (p = 0.033). In individuals with CAC, tooth loss correlated more strongly with the eGFR, and the correlation between OPN and OCN levels was more apparent. CONCLUSION: Dental patients with CAC and increased tooth loss have a greater tendency for decreased renal function, which may be associated with OPN and OCN; thus, these patients should be referred for investigation.

Branching patterns of the inferior alveolar canal in a Thai population: a novel classification using cone beam computed tomography.

OBJECTIVE: This aim of this study was to determine the prevalence and branching patterns of the inferior alveolar canal (IAC) in premolar and molar areas using cone beam computed tomography (CBCT). METHOD AND MATERIALS: CBCT volumes from partially or fully edentulous premolar and molar areas were investigated retrospectively. The presence of such branches with their patterns, sides, and areas, as well as the sex of the patient, were recorded by two observers and analyzed statistically. The branching patterns were initially classified into three types: A, superior type; B, forward type; and C, plexus type. During the investigation, an additional type was found in the premolar area and was classified as type D, an anterior extension type. RESULTS: In total, 243 mandibular sites in 176 subjects were included. Among them, 106 sites displayed branches (43.62%). In the premolar area, most branches were of the anterior extension type (D, 33%), followed by the superior and plexus types (A and C, respectively, 29%), and the forward type (B, 9%). In the molar area, the plexus type was the most common finding (C, 39%), followed by the superior type (A, 32%) and the forward type (B, 29%). Branches in the molar area were significantly more frequent in men than in women (P = .011). CONCLUSION: IAC branches with four branching patterns in the premolar and molar areas are not rare and could be detected by CBCT. Clinicians should be aware of these branches during surgical procedures concerning the posterior mandible.

The retromolar canal and its variations: Classification using cone beam computed tomography.

OBJECTIVE: To determine the prevalence of the retromolar canal and its various patterns using cone beam computed tomography (CBCT). METHOD AND MATERIALS: CBCT images with the presence of mandibular third molars from August 2013 to May 2015 were retrospectively investigated. The presence of retromolar canal, its patterns, sides, as well as gender were evaluated by two observers. The pattern of retromolar canal was initially classified into three types: Type A, superior type; Type B, radicular-retromolar type; and Type C, dental type. During the investigation, two additional types were found and further classified: Type D, plexus type; and Type E, forward type. The distribution of retromolar canals between genders and sides was statistically analyzed with Pearson's chi-square test. RESULTS: A total of 201 mandibular sites in 156 subjects (99 women, 57 men) were included. Among them, 128 sites had retromolar canals (63.68%). The presence of retromolar canal was not statistically related to gender or side. Most of the retromolar canals were the radicular-retromolar type (Type B, 38.10%), followed by the superior type (Type A, 29.93%), dental type (Type C, 19.73%), plexus type (Type D, 6.80%), and forward type (Type E, 5.44%). CONCLUSION: There was a high frequency of retromolar canals and these could be classified into five patterns. The clinician should be aware of this anatomical structure when performing surgical procedures involving the retromolar area.

Inverse Association of Plasma IgG Antibody to Aggregatibacter actinomycetemcomitans and High C-Reactive Protein Levels in Patients with Metabolic Syndrome and Periodontitis.

The association between clinically diagnosed periodontitis, a common chronic oral infection, and metabolic syndrome has been previously reported. The aim of this study was to investigate the association of plasma IgG levels against Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia, C-reactive protein, and periodontal status with metabolic syndrome. Plasma IgG levels and C-reactive protein were measured by enzyme-linked immunosorbent assay, and salivary levels of A. actinomycetemcomitans and P. gingivalis were determined by quantitative real-time polymerase chain reaction. Among 127 individuals aged 35-76 years, 57 participants had metabolic syndrome and severe periodontitis, 25 had metabolic syndrome and an absence of severe periodontitis, 17 healthy individuals had severe periodontitis, and 28 healthy individuals were without severe periodontitis. Patients with metabolic syndrome had reduced humoral immune response to A. actinomycetemcomitans (p = 0.008), regardless of their salivary levels or periodontitis status compared with healthy participants. The IgG antibody response to P. gingivalis, regardless of their salivary levels or participants' health condition, was significantly higher in severe periodontitis patients (p<0.001). Plasma IgG titers for P. intermedia were inconsistent among metabolic syndrome or periodontal participants. Our results indicate that the presence of lower levels of IgG antibodies to A. actinomycetemcomitans (OR = 0.1; 95%CI 0.0-0.7), but not P. gingivalis, a severe periodontitis status (OR = 7.8; 95%CI 1.1-57.0), high C-reactive protein levels (OR = 9.4; 95%CI 1.0-88.2) and body mass index (OR = 3.0; 95%CI 1.7-5.2), are associated with the presence of metabolic syndrome. The role of the decreased IgG antibody response to A. actinomycetemcomitans, increased C-reactive protein levels on the association between periodontal disease and metabolic syndrome in a group of Thai patients is suggested.

Accuracy of linear measurements using cone beam computed tomography and panoramic radiography in dental implant treatment planning.

PURPOSE: The aim of this study was to investigate the accuracy of linear measurements from cone beam computed tomography (CBCT) images and digital panoramic radiographs at various implant sites. MATERIALS AND METHODS: Fifty implant sites from six skulls were marked with gutta-percha and subjected to CBCT with five different voxel protocols: 0.125 mm, 0.160 mm, and 0.250 mm with the 3D Accuitomo 170 CBCT machine and 0.200 mm and 0.300 mm with the CS 9500 CBCT machine. Images were also taken with the CS 9000 panoramic machine with three protocols: normal head, chin-up, and chin-down positions. Electronic linear measurement of bone height using the corresponding machine's software was recorded by two observers. Physical measurement using a digital caliper with ± 0.02-mm accuracy was directly recorded at the corresponding regions as the gold standard. All image measurements were compared with the physical measurements. The paired sample correlations for physical measurement, mean difference, standard deviation, absolute error, absolute percentage error, and inter- and intraobserver reliability were calculated. RESULTS: Intraobserver and interobserver reliability was more than 0.99. Paired sample correlation between all image measurements and physical measurements was considered statistically significant at P < .05. All image measurements were underestimated by less than 2 mm, except for the chin-down position of the maxilla in the panoramic radiograph. The absolute error and absolute percentage error in the mandible were less than those in the maxilla, and values obtained with CBCT were less than those from panoramic radiographs. CONCLUSION: CBCT images using the 3D Accuitomo 170 and CS 9500 machines and digital panoramic radiographs via a picture archiving and communication system are sufficiently accurate for vertical linear measurements in dental implant treatment planning.

Relationship between calcified carotid atheromas in digital panoramic radiographs and underlying systemic diseases in implant patients.

AIM: The aim of the present study was to evaluate the correlation between calcified carotid atheromas (CCA) detected on digital panoramic radiographs and underlying systemic diseases. METHODS: Panoramic radiographs and underlying systemic diseases of retained mandibular denture implants in 265 patients (56 males, 209 females) aged over 50 years were retrospectively evaluated at the Dental Unit of Prasat Neurological Institute, Bangkok, Thailand. RESULTS: The mean age of the patients was 71 ± 7.1 years. The prevalence of CCA was 38.49%. The major underlying systemic diseases were hypertension, hyperlipidemia, diabetes mellitus, and cardiovascular diseases (CVD), respectively. No relationship was found among these four systemic diseases in detecting CCA on panoramic radiographs. Similar findings were also observed in patients with only one systemic disease versus in combination with other diseases. CONCLUSIONS: The presence of CCA on dental panoramic radiographs was not found to be related to the presence of underlying systemic diseases, including hypertension, hyperlipidemia, diabetes mellitus, and CVD.

The prevalence of carotid artery calcifications detected on panoramic radiographs in patients with metabolic syndrome.

OBJECTIVES: The purpose of this study was to determine the prevalence of carotid artery calcifications (CAC) detected on panoramic radiographs in patients with metabolic syndrome (MetS). STUDY DESIGN: Eighty-five Thai subjects (29 men, 56 women) who had MetS according to the International Diabetes Federation definition were evaluated for CAC detected on panoramic radiographs. The confirmation of findings was done by ultrasonography. RESULTS: Carotid artery calcifications were detected in 19 subjects (22.4%) with a mean age of 64 years, range 48-74 years. These subjects included 12 men and 7 women. The CAC were significantly more common in men than in women (P = .002). There were 8 subjects (9.4%) with bilateral calcifications and 11 subjects (12.9%) with unilateral calcification. No significant difference between the right and left sides was found (P = .44). CONCLUSION: Thai people with MetS have high prevalence of radiographically detectable carotid artery calcifications.

Decorin modulates collagen matrix assembly and mineralization.

Decorin (DCN) is one of the major matrix proteoglycans in bone. To investigate the role of DCN in matrix mineralization, the expression of DCN in MC3T3-E1 (MC) cell cultures and the phenotypes of MC-derived clones expressing higher (sense; S-DCN) or lower (antisense; AS-DCN) levels of DCN were characterized. DCN expression was significantly decreased as the mineralized nodules were formed and expanded in vitro. In S-DCN clones, in vitro matrix mineralization was inhibited, whereas in AS-DCN clones, mineralization was accelerated. At the microscopic level, collagen fibers in S-DCN clones were thinner while those of AS-DCN clones were thicker and lacked directionality compared to the controls. At the ultrastructural level, the collagen fibrils in S-DCN clones were markedly thinner, whereas those of AS-DCN clones were larger and irregular in shape. The results from Fourier transform infrared spectroscopy analysis demonstrated that in AS-DCN cultures the mineral content was greater but the crystallinity of mineral was poorer than that of the controls at early stage of mineralization. The in vivo transplantation assay demonstrated that no mineralized matrices were formed in S-DCN transplants, whereas they were readily detected in AS-DCN transplants at 3 weeks of transplantation. The areas of bone-like matrices in AS-DCN transplants were significantly greater than the controls at 3 weeks but became comparable at 5 weeks. The bone-like matrices in AS-DCN transplants exhibited woven bone-like non-lamellar structure while the lamellar bone-like structure was evident in the control transplants. These results suggest that DCN regulates matrix mineralization by modulating collagen assembly.

Carotid artery calcification detected on panoramic radiographs in a group of Thai population.

OBJECTIVE: To determine the prevalence of carotid artery calcification (CAC) detected on panoramic radiographs in a Thai population. STUDY DESIGN: The panoramic radiographs of the patients 50 and older (N = 1,370) visiting Mahidol University from January 1998 through September 2004 were retrospectively reviewed for CAC. The medical records of the positive subjects were then reviewed. RESULTS: Thirty-four (2.5%) of the 1,370 patients, 16 men and 18 women, with a mean age of 69 and a range of 50 to 87 years, had 1 or more CACs. These calcifications were unilateral in 25 (73.5%) and bilateral in 9 (26.5%) subjects. Of those positive subjects, 18 reported hypertension, 10 reported diabetes mellitus, and 5 reported hyperlipidemia. CONCLUSIONS: Although it is uncommon to find CAC in the Thai population, dentists should be aware of this calcification on the routine panoramic radiographs and promptly refer for cerebrovascular and cardiovascular evaluation.