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This study aimed to systematically compare Neolithic mandibles and dentition with modern Chinese, and thereby discern human evolutionary trends.Neolithic remains of 45 adults unearthed at the Zhangqiu Jiaojia site, were compared with clinical records of 48 patients at Shandong University. All samples were scanned by cone beam computed tomography (CBCT) using identical parameters. Digital imaging and communications in medicine images were collected, three-dimensional models reconstructed, and morphology measurements obtained using Mimics software.Neolithic mandibles were significantly larger in their vertical and sagittal dimensions (P .05), but similar in horizontal width to modern humans. Their condyles had fewer bird beak and crooked finger shaped morphologies than modern mandibles (P .05). Neolithic third molars were more often erupted than in modern mandibles, and their Position A, class I and II, and vertical impactions were more common (P .05). Neolithic teeth were generally smaller in crown lengths and in cross-sectional areas, than their modern counterparts (P .05).Neolithic mandibles were larger than modern humans, who have refined diets and mandibular atrophy. They had fewer abnormally shaped condylar morphologies, and much fewer third molar impactions than in modern humans. However, modern dentition particularly their crowns are larger, likely through genetic influx from migrations.

Objective This study aimed to characterize Neolithic human maxillary molars from archeological remains at the Jiaojia site, Shandong, China, and compare their ultrastructural features with sex and age-matched modern locals. Design Maxillary first (n = 86) and second (n = 80) molars in 5000-year-old individuals (n = 50) from the Jiaojia site were scanned by cone-beam computed tomography (CBCT). Sex and age-matched control groups were assigned from oral surgical patients at Shandong University. Images were analyzed for crown size, root length, root morphology, canal inter-orifice distances, mesiobuccal canal morphology, and second mesiobuccal (MB2) canal prevalence and location. Neolithic and modern values were compared statistically using Chi-squared and Mann-Whitney test at p Results Crown and root size were smaller, and canal inter-orifice distances were shorter in Neolithic maxillary molars than their modern counterparts. For mesiobuccal roots, Weine’s Type I single canals were the most prevalent in Neolithic and modern first and second molars. MB2 canal prevalence were not significantly different (p > .05) in Neolithic (53.3%) or modern (60.5%) first molars, and Neolithic (11.3%) or modern (21.3%) second molars. But, MB2 prevalence was significantly higher for modern than ancient male first (p = .032) and second (p = .005) molars. Additionally, MB2 were located more mesially and closer to MB1 in Neolithic than modern molars. Conclusions Maxillary molar root and canal morphology of ancient 5000-year-old remains at the Jiaojia site resemble that of local patients. A trend towards larger tooth size, and more dispersed MB2 canals over this short evolutionary period warrants additional investigation.

BACKGROUND Schoolchildren are in a developmental period whose permanent teeth replace primary dentition. It is also a period with a high incidence of gingivitis and caries, which can be improved with correct tooth brushing. Advances in information technology have led to the development of smart health devices that assist in tooth brushing. OBJECTIVE To compare the effectiveness of computer-assisted toothbrushing using a toothbrushing instruction (TBI) method called the smart toothbrush and smart mirror (STM) system with that of conventional TBI for plaque control in schoolchildren. METHODS This randomized controlled clinical trials analyzed and compared the reduction of the modified Quigley-Hein plaque index between the two methods in 42 schoolchildren. The participants were randomly assigned to an STM system group (n=21) or a conventional-TBI group (n=21). The plaque indexes were evaluated at baseline, immediately after TBI (day 0), and 1 week and 1 month after TBI. RESULTS The STM system and conventional TBI led to an average reduction of 40.50% and 40.57%, respectively, in whole mouth plaque. Reductions in the plaque indexes in each time period tested were observed in both groups (P CONCLUSIONS The computer-assisted STM system showed a similar efficacy for dental plaque control in children compared with conventional TBI. The STM system may be beneficial for maintaining oral hygiene by improving tooth brushing ability. CLINICALTRIAL ClinicalTrials.gov NCT04627324； https://clinicaltrials.gov/ct2/show/NCT04627324

Objective: The aim of this study was to compare the effectiveness of five intracanal agitation techniques on the penetration of irrigant and sealer into dentinal tubules. Background data: Intracanal agitation techniques could promote chemomechanical debridement and the sealing of root canals during endodontic treatment. However, there is limited evidence for the agitation effect of Nd:YAP laser. Materials and methods: Human maxillary premolars with single straight canals (N = 60) were prepared with ProTaper Next® NiTi rotary files (Dentsply Maillefer) up to X4 (ISO 40 size). Rhodamine B-labeled sodium hypochlorite was used for final irrigation together with the conventional syringe (control), sonic, ultrasonic, Nd:YAP laser, or V-Clean™ endodontic agitation system. All canals were obturated with gutta-percha and fluorescein isothiocyanate-labeled AH Plus sealer. Transverse sections were obtained at 2, 5, and 8 mm from the apex and observed under confocal laser scanning microscopy. Maximum penetration depth and penetration percentage of both irrigant and sealer were recorded. Kruskal-Wallis and Mann-Whitney tests were performed for multiple comparisons. The Spearman coefficient was calculated to confirm correlations between irrigant and sealer penetration. Results: Laser agitation attained the most irrigant and sealer penetration depth and penetration percentage (p < 0.05). Sonic and ultrasonic agitation attained significantly more penetration percentage than the control group at 2 mm from the apex (p < 0.05). Patterns of irrigant and sealer penetration correlated significantly for all agitation techniques (p < 0.001). Conclusions: Nd:YAP laser was superior to other agitation techniques in dentinal tubule penetration of irrigant and sealer at one or more sectioned levels from the apex.

BACKGROUND High-quality photos are critical for the remote diagnosis of dental trauma and thus are beneficial to the prognosis. The quality of the images obtained using a cell phone depends on the level of dental and photography knowledge of the person who is taking the photos. OBJECTIVE This study aimed to determine the efficacy of photography education in improving images used for the remote diagnosis of dental trauma. METHODS The subjects comprised 30 laypeople and 30 dentists who were randomly assigned to 15 subgroups with 2 subjects in each. Each subject was asked to take photos of their own anterior teeth and those of their partner on the assumption that an accident occurred using both an iPhone 4s and iPhone 6. Education about how to take an appropriate photo of the anterior teeth for teleconsultation purposes was then provided, after which photos were taken again. Photos were assessed by a dentist for their usefulness in diagnosis. RESULTS This study analyzed 965 photos: 441 taken by laypeople and 524 taken by dentists. Photos taken after providing education had significantly higher scores for all assessment items than those taken before education (PP CONCLUSIONS Both laypeople and dentists might find photography education useful for when they are taking photos to be used in teleconsultations. The type of cell phone does not significantly affect the usefulness of such photos.

Background High-quality photos are critical for the remote diagnosis of dental trauma and thus are beneficial to the prognosis. The quality of the images obtained using a cell phone depends on the level of dental and photography knowledge of the person who is taking the photos. Objective This study aimed to determine the efficacy of photography education in improving images used for the remote diagnosis of dental trauma. Methods The subjects comprised 30 laypeople and 30 dentists who were randomly assigned to 15 subgroups with 2 subjects in each. Each subject was asked to take photos of their own anterior teeth and those of their partner on the assumption that an accident occurred using both an iPhone 4s and iPhone 6. Education about how to take an appropriate photo of the anterior teeth for teleconsultation purposes was then provided, after which photos were taken again. Photos were assessed by a dentist for their usefulness in diagnosis. Results This study analyzed 965 photos: 441 taken by laypeople and 524 taken by dentists. Photos taken after providing education had significantly higher scores for all assessment items than those taken before education (P Conclusions Both laypeople and dentists might find photography education useful for when they are taking photos to be used in teleconsultations. The type of cell phone does not significantly affect the usefulness of such photos.

Purpose The purpose of this study was to evaluate the relationship between masseter muscle thickness, facial morphology, and mandibular morphology in Korean adults using ultrasonography. Materials and methods Ultrasonography was used to measure the masseter muscle thickness bilaterally of 40 adults (20 males, 20 females) and was performed in the relaxed and contracted states. Facial photos and panoramic radiography were used for morphological analyses and evaluated for correlations with masseter muscle thickness. We also evaluated the correlations of age, body weight, stature, and body constitution with masseter muscle thickness. Results In the relaxing, the masseter was 9.8±1.3 mm in females and 11.3±1.2 mm in males. In the contracted state, it was 12.4±1.4 mm in females and 14.7±1.4 mm in males. Facial photography showed that bizygomatic facial width over facial height was correlated with masseter muscle thickness in both sexes in the relaxed state, and was statistically significantly correlated with masseter muscle thickness in males in the contracted state. In panoramic radiography, correlations were found between anterior angle length and posterior angle length and masseter muscle thickness in females, and between body length and posterior angle length, between anterior angle length and body length, between ramal length and body length, and between body length and condyle length in males. Conclusion Masseter muscle thickness was associated with facial and mandibular morphology in both sexes, and with age in males. Ultrasonography can be used effectively to measure masseter muscle thickness.

The objective of this study was to compare the efficacy of computer-assisted TBI using a smart toothbrush (ST) and smart mirror (SM) in plaque control to that of conventional TBI. We evaluated the plaque removal efficacy of a ST comprising a computer-assisted, wirelessly linked, three-dimensional (3D) motion-capture, data-logging, and SM system in TBI. We also evaluated the efficacy of TBI with a ST and SM system by analyzing the reductions of the modified Quigley-Hein plaque index in 60 volunteers. These volunteers were separated randomly into two groups: conventional TBI (control group) and computer-assisted TBI (experimental group). The changes in the plaque indexes were recorded immediately, 1 week, 1 month, and 10 months after TBI. The patterns of decreases in the modified Quigley-Hein plaque indexes were similar in the two groups. Reductions of the plaque indexes of both groups in each time period were observed (P

Objective To evaluate the change in mandibular second-molar (M2) angulation in orthodontic treatment with premolar extraction and lower third molar (M3). Study Design Panoramic radiographs were evaluated in 3 groups of 129 participants: (1) control, no orthodontic treatment (n = 65); (2) extraction, orthodontic treatment with premolar extraction (n = 30); and (3) nonextraction, orthodontic treatment without premolar extraction (n = 34). The angular difference and ratio of M2 to the first molar (M1), the change in the angulation of M2 between pre- and postorthodontic treatment, and the distal bone level of M2 were assessed. Results The angular difference and ratio of M2 to M1, the angulation change of M2 between pre- and postorthodontic treatment, and the distal bone level of M2 were higher in the nonextraction group than in the control and extraction groups. Conclusions The successful orthodontic alignment of the M2 may not be achieved in nonextraction cases when the M3s are present.

In this study, we propose the unsupervised image segmentation algorithm to estimate dental plaque accumulations on digital imaging with methylene blue disclosed plaque. With this aim, RGB color plane is mapped into HSI coordinates and the circular histogram of Hue is reconstructed by applying Otsu's threshold level. The histogram distribution on Saturation features is also analyzed by maximizing the variance between a plaque candidate and non-plaque one. The dental plaque regions are resolved by applying the composite decision logics based on the threshold level of Hue and Saturation.

In this paper we show that the flat property of a left R- module does not imply (carry over) to the corresponding inverse polyno- mial module. Then we define an induced inverse polynomial module as an R(x)-module, i.e., given an R-linear map f : M ! N of left R-modules, we define N +x i1 M(x i1 ) as a left R(x)-module. Given an exact sequence of left R-modules 0 i! N i! E 0 i! E 1 i! 0, where E0,E1 injective, we show E1 + xi1E0((xi1)) is not an injective left R(x)-module, while E0((xi1)) is an injective left R(x)-module. Make a left R-module N as a left R(x)-module by xN = 0. We show injdimR N = n implies injdimR(x) N = n + 1 by using the induced inverse polynomial modules and their properties.

PURPOSE The aim of this study was to determine the absolute value of the root/crown ratio (R/C ratio) using panoramic radiographs (PRGs) in a healthy Korean population. MATERIALS AND METHODS In total, 99 patient radiographs (of 50 males and 49 females subjects; aged 16 to 24 years old) were examined, and 2,770 teeth were analyzed. Crown lengths and root lengths were measured with modified Lind's measurements using PACS tools by two examiners in two separate sessions two months apart. All data were analyzed using SPSS. The independent t-test was used to assess for gender differences, and the paired t-test was used to compare both arches with a significance level of P

Purpose : Dental trauma is frequently unpredictable. The initial assessment and urgent treatment are essential for dentists to save the patient’s teeth. Mobile-phone-assisted teleconsultation and telediagnosis for dental trauma could be an aid when a dentist is not available. In the present in-vitro study, we evaluated the success rate and time to transfer images under various conditions. Materials and Methods : We analyzed the image quality of cameras built into mobile phones based on their resolution, autofocus, white-balance, and anti-movement functions. Results : The image quality of most built-in cameras was acceptable to perform the initial assessment, with the autofocus function being essential to obtain high-quality images. The transmission failure rate increased markedly when the image size exceeded 500 kB and the additional text messaging did not improve the success rate or the transmission time. Conclusion : Our optimal protocol could be useful for emergency programs running on the mobile phones. (Imaging Sci Dent 2012; 42 : 71-5)

In this paper, we described the intelligent toothbrush system which is capable of monitoring three-dimensional brushing motion of toothbrush and analyzing brushing regions based on sensor signals measured from built-in accelerometer and magnetic sensors. In order to evaluate the efficacy of the proposed toothbrush system, we performed two experiments. First, all subjects are asked to brush their teeth freely without any restrictions, and brushing motions were recorded and evaluated for the time duration of each possible brushing regions. Then, all subjects were received toothbrushing instruction(TBI) and encouraged to follow basic TBI for a week. Second, subjects were asked to brush their teeth freely again. Data from previously performed experiments are compared with time durations of each brushing region. The result shows that time distributions of each regions in the second experiment became more uniform than the first brushing. The ratios of time distributions of each brushing regions is increased, and the overall toothbrushing times increased from 107 sec to 225 sec (p

Objective The aim of this study was to investigate the types of canal configurations and the incidence of a second mesiobuccal (MB2) canal in Korean maxillary molar mesiobuccal (MB) roots by analyzing cone-beam computed tomographic (CBCT) images. Study design Three-dimensional CBCT images of 458 maxillary first molars and 467 second molars from 276 Korean patients were analyzed to determine the incidence of an MB2 canal, the types of canal configurations, and the correlations between the incidence of an MB2 canal and age, gender, and tooth position. Results The incidence of 2-canaled MB roots was 71.8% in first molars and 42.2% in second molars, with the most common configurations being Weine types III and II. The frequency of an MB2 canal decreased with age in both molars (P Conclusions Types III and II canal configurations were the most prevalent in the 2-canaled MB roots of Korean maxillary molars.