Enhancing teeth segmentation using multifusion deep neural net in panoramic X-ray images.

BACKGROUND: Precise teeth segmentation from dental panoramic X-ray images is an important task in dental practice. However, several issues including poor image contrast, blurring borders of teeth, presence of jaw bones and other mouth elements, makes reading and examining such images a challenging and time-consuming task for dentists. Thus, developing a precise and automated segmentation technique is required. OBJECTIVE: This study aims to develop and test a novel multi-fusion deep neural net consisting of encoder-decoder architecture for automatic and accurate teeth region segmentation from panoramic X-ray images. METHODS: The encoder has two different streams based on CNN which include the conventional CNN stream and the Atrous net stream. Next, the fusion of features from these streams is done at each stage to encode the contextual rich information of teeth. A dual-type skip connection is then added between the encoder and decoder to minimise semantic information gaps. Last, the decoder comprises deconvolutional layers for reconstructing the segmented teeth map. RESULTS: The assessment of the proposed model is performed on two different dental datasets consisting of 1,500 and 1,000 panoramic X-ray images, respectively. The new model yields accuracy of 97.0% and 97.7%, intersection over union (IoU) score of 91.1% and 90.2%, and dice coefficient score (DCS) of 92.4% and 90.7% for datasets 1 and 2, respectively. CONCLUSION: Applying the proposed model to two datasets outperforms the recent state-of-the-art deep models with a relatively smaller number of parameters and higher accuracy, which demonstrates the potential of the new model to help dentists more accurately and efficiently diagnose dental diseases in future clinical practice.

Impact Strength of Various Types of Acrylic Resin: An In Vitro Study.

AIM: The aim of this study is to evaluate and compare the impact strength of conventional acrylic resin, high-impact acrylic resin, high-impact acrylic resin reinforced with silver nanoparticles, and high-impact acrylic resin reinforced with a zirconium oxide powder. MATERIALS AND METHODS: A total of 60 samples were prepared of dimensions 60 mm length × 7 mm width × 4 mm thickness to test impact strength. Machined stainless steel dies of the same dimension were used to form molds for the fabrication of these samples. Of 60 samples, 15 samples were prepared each from conventional acrylic resin (Group A1), high-impact acrylic resin (Group A2), acrylic resin reinforced with silver nanoparticles (Group A3), and acrylic resin reinforced with zirconium oxide powder (Group A4). Izod-Charpy pendulum impact testing machine was used. RESULTS: The impact strength of group A1 was in the range of 2.83-3.30 kJ/m2 (M = 3.12 kJ/m2, SD = 0.16), group A2 was in range of 5.10-5.78 kJ/m2 (M = 5.51 kJ/m2, SD = 0.18), group A3 was in range 3.18-3.56 kJ/m2 (M = 3.37 kJ/m2, SD = 0.11), and group A4 was in range 7.18-7.78 kJ/m2 (M = 7.5 kJ/m2, SD = 0.18). Statistical analysis using one-way ANOVA and t-test revealed significant differences (p < 0.001). CONCLUSION: High-impact acrylic resin reinforced with zirconium oxide powder has the highest impact strength. CLINICAL SIGNIFICANCE: This research sheds light on the usefulness of novel filler materials in clinical prosthodontics.

Validity and reliability of intraoral conventional tracer and intraoral digital tracer in different positions for recording horizontal jaw relation in edentulous patients.

AIM: The purpose of the study is to evaluate and compare the horizontal mandibular positions recorded between intraoral conventional tracer and intraoral digital tracer in upright and supine position. MATERIALS AND METHODS: Twenty-four edentulous patients with well-formed ridge and adequate interarch distance space were selected. MATLAB software was assimilated with intraoral digital tracer and was utilized in the study for recording the horizontal movements of the mandible, i.e., gothic arch tracing by intraoral digital tracer and was observed on a laptop with the help of MATLAB Software. For each subject, multiple mandibular readings were recorded and analyzed through software, and similar readings were recorded with conventional intraoral tracers. The comparison between intraoral conventional tracer and intraoral digital tracer was done to assess the reliability. Moreover, the consistency of recording horizontal mandibular position was also compared between upright and supine position. RESULTS: The data were procured and utilized in comparison for different positions revealed statistically significant difference by using Student's Paired t-test. The test resulted in supine position better compared to upright position (P = 0.0001). The association between supine position with upright position was calculated using Fischer's exact test, and it was also found to be statistically significant (P = 0.002). The Pearson's Correlation analysis was performed to check the agreement between upright and supine position and very weak downhill correlation (r 2= -0.130) was observed between the two variables. CONCLUSION: On evaluation and comparison of horizontal mandibular position, it was found that the intraoral digital tracing technique is more valid compared to conventional intraoral tracer technique. It was also observed that the consistency of reproducibility in recording horizontal mandibular position in supine position is significantly higher than upright position.

Exploiting multimodal CNN architecture for automated teeth segmentation on dental panoramic X-ray images.

Panoramic X-ray images are the major source used in field of dental image segmentation. However, such images suffers from the disturbances like low contrast, presence of jaw bones, nose bones, spinal bone, and artifacts. Thus, to observe these images manually is a tedious task, requires expertise of dentist and is time consuming. Hence, there is need to develop an automated tool for teeth segmentation. Recently, few deep models have been developed for dental image segmentation. But, such models possess large number of training parameters, thus making the segmentation a very complex task. Also, these models are based only on conventional CNN and lacks in exploiting multimodal CNN features for dental image segmentation. Thus, to address these issues, a novel encoder-decoder model based on multimodal-feature extraction for automatic segmentation of teeth area is proposed. The encoder has three different CNN based architectures: conventional CNN, atrous-CNN, and separable CNN to encode rich contextual information. Whereas decoder contains a single stream of deconvolutional layers for segmentation. The proposed model is tested on 1500 panoramic X-ray images and uses very less parameters when compared to state-of-the-art methods. Besides this, the precision and recall are 95.01% and 94.06%, which out performs the state-of-the art methods.

Assessment of dental anxiety and its correlation with denture satisfaction in edentulous patients.

OBJECTIVE: The objectives of this study were to measure the level of dental anxiety and its correlation with dental history, denture satisfaction and other variables. MATERIALS AND METHODS: A cross-sectional study was conducted on 150 completely edentulous patients reporting to the Department of Prosthodontics, KLES's Institute of Dental Sciences, Belgaum, over a period of 17 months (August 2005 to March 2007). The anxiety level of the patients was assessed with the help of a questionnaire, after obtaining an informed consent. Reliability of the dental anxiety scale was assessed by means of coefficient alpha. RESULTS: The results of this study concluded that dental anxiety scale for edentulous patients was a reliable scale for measuring dental anxiety. The anxiety score was higher for female than male patients. A significant correlation was found between denture satisfaction score and anxiety. DISCUSSION: Anxiety plays a major role in denture satisfaction. The variables included: Previous denture experience, occupation, medical history, age, gender, dental anxiety scale, period of edentulousness, age of previous dentures, number of complete dentures, denture satisfaction score, and the score on the Hamilton anxiety scale. CONCLUSION: The study indicated that gender correlates significantly with dental anxiety. Patients with medical history were found to be more anxious than normal patients. Patients with higher anxiety values were less satisfied with the treatment. Lastly, subjects with higher general anxiety showed greater values on the dental anxiety scale. CLINICAL SIGNIFICANCE: The assessment of dental anxiety will help the prosthodontist in the management of anxious patients and secondly to provide evidence-based research into this psychological construct which has been shown to predict dental avoidance.

A review on traditional practice of tooth brushing in Ayurveda and its relevance in current era.

Ayurveda recommends sound and healthy life. It basically focuses on prevention rather than treatment. It includes a systematic lifestyle pattern which is composed of several principles and activities. Dinacharya (Daily routine) is one of the important principles. It includes various activities started from just before sunrise. All these activities are necessary for the maintenance of homeostasis of the body. Tooth brushing is one of the essential routines of Ayurveda daily practices. Traditionally it has been advocated with a soft twig of medicinal plants with or without herbal tooth powder. There are so many medicinal plants have been described in this context. Contradictory plants have also been described. Oral hygiene products are so much advanced and globalized nowadays. There are so many types of toothbrushes; dentifrices, dental floss, tongue scrapers, mouthwashes, oral irrigators, etc. are available along with specifications. Contemporary oral hygiene products esp. dentifrices are chemically rich and have their own side effects. No doubt these products have their own advantages like easy availability and adjustability according to current lifestyle. But their safety is questionable on long-term use. Herbal products have additional benefits over it that those are natural and easily adjustable and acceptable with body physiology.