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An approach, computational shape analysis (CSA), is presented here which utilizes a Fourier-wavelet representation to numerically describe shape features of biological forms. Two elements are involved: 1) elliptical Fourier functions (EFFs), to provide estimates of global aspects, and 2t continuous wavelet transforms (CWTs) to generate an objective estimate of localized features. EFFs are computed, using a set of pseudohomologous points, to create a precise analog of the boundary. This computed contour is then normalized by scaling and rotated in two-dimensional space to insure a representation that is invariant with respect to starting point, size, and orientation. The predicted point coordinates derived from the EFFs are submitted to CWT for further processing. Wavelet coefficients are then computed to identify localized features, localization being a subjective process with EFFs. The advantage of wavelets is that they eliminate the inevitable subjectivity inherent in the choice of measurements. To test the usefulness of CSA, a sample of cranial base (CB) lateral radio graphic outlines was available. Five archaeological periods, Yayoi, Kofun, Kamakura, Edo, and Modern, were utilized (n = 297). Statistically significant differences in sex and archaeological age were found. Although archaeological age differences were present, they were small and random in character, suggesting stability in the CB structures. In contrast, sexually dimorphic differences were present in every group from the Yayoi to the Modern period. This presence of sexually dimorphic differences in shape was consistent with earlier studies of M. nemestrina, G. gorilla, and P. troglodytes. Consequently, it is suggested that the pattern of sexual dimorphism documented in the Japanese CB is a primate pattern with an ancient evolutionary history. The results demonstrate, both visually and numerically, that CSA is a powerful approach for describing both global and localized features of craniofacial structures such as the CB. KEY WORDS elliptical Fourier functions; continuous wavelet transform; computational shape analysis

The occlusal surfaces of the first upper molars of a Dutch population were measured three-dimensionally by moiré contourography. Cusps and ridges were higher than those of a Japanese population, but distances between cuspal tips were smaller. Differences in occlusal form may influence jaw movements in the two populations. [ABSTRACT FROM AUTHOR]

Relationships of cusp height between the upper and lower first molars and between the deciduous second molars in Japanese subjects were analyzed with the aid of moiré contourography. In permanent molars, the height of the hypoconid had a mean value similar to that of the upper trigonal cusps, indicating that upper and lower functional cusps of the same height occlude with each other. In deciduous second molars, however, hypoconid heights were significantly smaller than trigonal cusp heights. Such differences in cusp height between permanent and deciduous dentition may be related to the function and phylogeny of tooth or jaw movements. [ABSTRACT FROM AUTHOR]

Dental arch form in 5 Chinese minorities was metrically analyzed and the results were compared with other Asian and Pacific peoples. Materials were dental impression models of 5 Chinese minorities, Hani, Dai, Naxi, Pumi and Miao in Yunnan Province. They were placed under the system of arm-type 3D digitizer (Micro Scribe 3DX) and the landmarks were plotted. Arch width was represented by 9 parameters and the arch length was represented by 8 parameters with the use of the program of CADKEY2000. Principal component analysis elucidated that general dental arch size of Yunnan Chinese minorities was small and relatively short compared with other Asian and Pacific populations in males and females. They were smaller than Japanese especially in the lower dentition. The arch size and shape of these minorities might depend on their small tooth size. Among 5 groups, Hani had a larger arch, but Miao had a smaller one than other groups. In the sex combined analysis, it was generally clear that male's arch was larger in size and broader in shape in all of the populations studied. [ABSTRACT FROM AUTHOR]

Non-carious cervical lesions (NCCLs) are characterized by the loss of hard tissue at the cementenamel junction (CEJ) in the absence of caries. Various forms of NCCLs had been observed in former studies. However, the frequency of each form had not been investigated. It is generally accepted that initiation and progression of NCCLs have a multi-factorial etiology. The most widely accepted causes of NCCLs are abfraction and abrasion, while other mechanisms such as erosion and corrosion have also been proposed. The aim of this study is to classify the morphology of NCCLs, to investigate the frequency of each form, and to consider their causes. We macroscopically observed 4000 extracted permanent teeth of the present-day Japanese under illumination at 10x magnification. NCCLs were classified by the combinations of the contour on the surface and the cross-sectional shape. NCCLs were most frequently found in the canine and the first premolar. The frequencies of NCCLs were high on the labial side in almost all type of teeth. At the same time, NCCLs were frequently observed also on the lingual side in the posterior and anterior teeth. Some forms were recognized characteristically in particular teeth. In the canine, the type of the "crescent" (contour on the surface) and "circle"(crosssectional shape) was most frequently observed. In the premolars, the frequency of "wedge"(crosssectional shape) was the highest. The morphologies of NCCLs have proved to be different among the types of teeth, which suggests that causes of NCCLs were different in the types of teeth. [ABSTRACT FROM AUTHOR]

Background and objectives In order to observe relationships between tooth crown traits and X chromosomal disorders in humans, we investigated Carabelli's trait and Hypocone reduction of maxillary first and second permanent molars in females with one and two extra X chromosome. Methods and subjects We obtained the data from dental casts belonging to Professor Lassi Alvesalo's Kvantti research project on sex chromosome abnormalities in Finland. The subjects comprised 5 47,XXX females, 2 48,XXXX females and 141 female normal controls from a rural community on Hailuoto island in Finland. Carabelli's trait was scored into three grades in Dahlberg's P12 (1956): grade (-) -- smooth surface, grade (±) -- pit or furrow, and grade (+) -- slight protuberance or cusp. Hypocone reduction was classified into two classes in Dahlberg's P9 (1951): a four-cusp pattern and a three-cusp pattern. Results The result showed that 47,XXX females and 48,XXXX females have higher frequencies of Carabelli's trait and of four-cusp pattern in M1 and M2 than control females. The statistical association between the expression of Carabelli's trait and four-cusp pattern were found to 47,XXX females, and 48,XXXX females relative to control females in M2. Conclusions Our result suggests that the additional X chromosome genetic material causes the higher frequency of the Carabelli's trait and four-cusp pattern and has influence on the patterning in cusp number. The possible association between Carabelli's trait and enamel thickness is discussed. [ABSTRACT FROM AUTHOR]

Previous studies have reported that compared to commoners in Japan's Edo period, samurai had long heads, more dental irregularities, and slightly worn teeth. However, these studies did not measure the mandible or only measured length. Angular analysis is essential to evaluate the maxillofacial morphology, but there are no comparative studies of samurai and commoners. This study explored the differences in maxillofacial morphology between samurai and commoners in the Edo period. Thirty male skeletons (samurai) and thirty-eight male skeletons (commoners) were used as materials from the National Museum of Nature and Science. The selected specimens were adults aged between 20 and 59 years without serious skeletal damage and with stable occlusion of the molars. We used three-dimensional scanning to measure the specimens' skeletal, alveolar, and facial widths. The mandibular plane angle and the gonial angle were significantly larger in the samurai than in the commoners. The ratio of the intermandibular first molars, interzygomatic arch, and mandibular width was significantly shorter in the samurai than in the commoners. The samurai had a high angle tendency and smaller mandibular width than the commoners, reflecting the class system.

Oxaliplatin(L-OHP)-related hypersensitivity reactions(HSRs)may be fatal due to bronchospasm, dyspnea, and hypotension. Therefore, management of HSRs is extremely important, and a prompt and appropriate response is required when HSRs develop. To clarify the importance of early detection and an appropriate initial response to HSRs, we retrospectively investigated the expression of HSRs and subsequent response in patients using L-OHP from April 2016 to December 2017 at the outpatient chemotherapy center of Nagasaki Medical Center. HSRs were observed in 14/155 cases(one case of Grade 1 HSRs and 13 cases of Grade 2 HSRs). No significant risk factors were identified in individuals with and without HSRs. HSRs devel- oped following a median of 7.9(2-11)courses of chemotherapy and a median 687.8(75.4-960.2)mg/m2 cumulative dose. Half of the patients were able to recognize the hypersensitivity early by themselves. Furthermore, nurses were able to implement an appropriate initial response. Early detection and an appropriate early response to HSRs can possibly prevent the severity of symptoms.

Non-carious cervical lesions (NCCLs) were examined in 6541 extracted human teeth and classified based on the morphology of the lesions. As a result, NCCLs were found on 38.7% of teeth (41.6% on maxillary teeth and 36.0% on mandibular teeth), and were most frequent on canines and first premolars. According to the new method of classification, the morphology of NCCLs was classified both by the surface contour (SC) and by the cross-sectional contour (CC). Three types of NCCLs appeared to be dominant. The causes of these NCCLs were discussed based on their morphologies, positions where these NCCLs were frequently found, and the results of previous studies. NCCLs with a horizontal oval SC and a round CC (Type I), which were frequent on the labial surfaces of maxillary canines and buccal surfaces of maxillary first premolars, may be associated with wear by friction and chemical degradation. NCCLs with a vertical oval SC and a round CC (Type II), which were frequent on the lingual surfaces of mandibular incisors and canines, might be mainly related to chemical degradation. NCCLs with a horizontal oval SC and a wedge shape CC (Type III), which were extensively found on the buccal surfaces of maxillary premolars, had formed most probably due to wear by friction and microstructural loss by stress. This new method can classify the morphology of NCCLs more precisely and deduce the mechanisms of the formation of NCCLs more clearly than former methods.

Aim: This retrospective cohort study evaluated the effectiveness of injury to the endometrium prior to the frozen-thawed embryo transfer (FET) cycle in patients with repeated implantation failure (RIF) in our clinic., Methods: Included in this study were 173 patients, aged ≤ 41 years, who failed to become pregnant after repeating fair and/or good embryo transfer more than twice between February 2012 and February 2015. The patients were divided into three groups: Group A (n = 38) underwent soft curettage to the endometrium twice, prior to the FET cycle; Group B (n = 45) underwent hysteroscopy prior to the FET cycle, with no significant factors, such as endometrial polyp; and Group C (n = 90) was the no-treatment group., Results: The clinical pregnancy rate per transfer was found to be statistically significant between Group A at 42.1% (16/38) and Group C at 22.2% (20/90). The crude and adjusted odds ratios (OR) were 2.55 and 2.49 (95% confidence intervals 1.13-5.78, P = 0.03 and 1.01-6.17, P = 0.048) respectively. Group B with only hysteroscopy had a higher pregnancy rate of 35.6% (16/45) than Group C, but showed no statistical significance (P = 0.103)., Conclusion: These results suggest that injuring the endometrium has a positive effect on pregnancy., (© 2016 Japan Society of Obstetrics and Gynecology.)

In order to clarify the morphological characteristics and function of the protuberance and/or fossa on the lateral surface of the mandible, we examined 778 mandibles of 9 genera, 19 species of non-human primates. Both protuberance and fossa were found in Macaca, Chlorocebus, and Cercocebus at frequencies ranging from 0% to 60%. The protuberance was composed of compact bone and was similar to the mandibular torus in humans. A well-developed protuberance extended from the fourth premolar to third molar region, and was situated at the central part of the mandibular body, or continued on the oblique line. Sometimes the protuberance localized on the mandibular base. A deep and large fossa was found in all individuals of Papio, Theropithecus, and Mandrillus, and the bone width was thin in the center of the fossa. The fossa extended from the third premolar to the second molar region, and the deepest area was the first molar region. In Macaca, Chlorocebus, and Cercocebus, the curvature of the external table of the mandible created a fossa. In Colobus, and Hylobates, the external surface of the mandible looked concave because of the thickened mandibular base. These concavo-convex structures have some biological functions and represent an adaptive change for mastication., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

The purpose of the present study is to investigate the pattern of fluctuating odontometric asymmetry of permanent mandibular first and second molars in a Japanese population. Dental plaster casts of 112 (57 males and 55 females) Japanese undergraduate dental students were used. The mesiodistal and buccolingual diameters of the whole crown and trigonid and talonid crown components were taken on the left and right sides of the mandibular permanent first and second molars. Crown areas were also calculated. The fluctuating asymmetry (FA) value was obtained by dividing the absolute side difference by the absolute mean size of the left and right teeth: FA = abs (R-L)/((R + L)/2). Fluctuating asymmetry between mandibular first and second molars was significantly different with the mandibular second molar showing higher asymmetry in both males and females. Meanwhile, fluctuating asymmetry between males and females in the first and second molars was not significantly different in all measured dimensions. With regard to trigonid and talonid components, fluctuating asymmetry of the distal talonid area was significantly larger than the mesial trigonid area in the mandibular permanent first molar of males (P < 0.01), and asymmetry of buccolingual diameter of the talonid was also larger than that of the trigonid in the mandibular permanent second molar of males (P < 0.05). In conclusion, these findings suggest that the crown dimensions of later developing teeth in the mandibular molar tooth class and crown component in the same molar tooth show more asymmetry and, therefore, are more affected by external factors.

The concentration level of extracellular L-glutamate released from region CA3 of mouse hippocampal slices under tetraethylammonium (TEA) chloride and KCl stimulation was measured with independent methods, i.e., a capillary-based enzyme sensor, a patch sensor, and an enzyme-based imaging method. The L-glutamate level was compared with those at regions CA1 and DG. It was found that the enhanced concentration level at CA3 by TEA stimulation is very similar to that at CA1, but it is much lower than that at DG. The order of the regional distribution of L-glutamate, i.e., DG > CA1 ≈ CA3, was the same as that obtained by K(+) stimulation. However, in the presence of an uptake inhibitor, DL-TBOA, KCl stimulation showed the strongest L-glutamate flux at CA1, while TEA stimulation exhibited the strongest flux at CA3. The usefulness of the present approach for knowing the extracellular L-glutamate level in acute hippocampal slices is discussed.

The purpose of this study was to evaluate the correlation and distribution of dental postgraduate residents, dentists and clinical training facilities in each prefecture to analyze the regional distribution and supply of dentists in Japan. The results were also compared with referential data for medicine. The coefficient of correlation between the dentist index and dental postgraduate resident index was r = 0.76 (P < 0.001) in 2006. The distribution (coefficient of variation) was greatest for the dental postgraduate resident index. The numbers of dentists per 100,000 population in prefectures with dental colleges were significantly higher in 1986, 1996 and 2006 for each comparison (P < 0.001). Coefficients of correlation between dentist index and dental postgraduate resident index were r = 0.65 (P < 0.01) in prefectures with dental colleges and r = 0.11 in those without dental colleges in 2006. The prefectures with high level of numbers of cooperative-type clinical training facilities had dental colleges.

Because children cannot be expected to take medications correctly by themselves, parents are responsible for administering drugs based on the information provided by pharmacists. It has been reported that 90% of children aged 3-5 years in Japan attend kindergarten or nursery school, where teachers are responsible for the administration of some drugs to children. This study evaluated the types of information that teachers receive from parents. We conducted a questionnaire-based survey on drug information imparted to 144 teachers working in kindergarten or nursery schools in Hiroshima and Kure. The teachers reported that drug information from parents mainly comprised dosage and usage. However, little information was provided concerning the drug name, adverse drug reactions, and interaction with food items. To administer drugs to children safely, kindergarten and nursery teachers considered the information regarding adverse drug reactions (111/123 teachers), interaction with foods (106/123 teachers), and effective means of administering drugs (117/123 teachers) as important. The pharmacists' prescription notes have information on dosage, usage, drug name, adverse drug reactions, and interaction with food items. However, the teachers receive drug information from parents in the order of oral communication, a written note, and via the pharmacists' prescription note. Seventy-two percent of teachers (89/123 teachers) insisted on needing the pharmacists' prescription note. These results suggest that teachers are uncomfortable administering medications to children primarily due to inadequate information. Pharmacists should instruct parents to provide teachers with prescription notes to prevent grave medication errors.

We used a glutamate oxidase (GluOx)-immobilized glass coverslip for reducing diffusional blur and improving the temporal resolution of visualizing L-glutamate fluxes in acute brain slices. The immobilization of GluOx on an avidin modified glass coverslips was achieved by optimized the amine coupling method. The GluOx coverslip was applied to the imaging of L-glutamate fluxes in acute hippocampal slices under hypoxia and KCl stimulation. A slice from mouse brain was loaded with horseradish peroxidase (HRP) and substrate DA-64, and placed on the GluOx coverslip for stimulation. The regional distribution of hypoxia-induced L-glutamate fluxes was analyzed. The maximum flux at 3 min after the onset of hypoxia increased in the order CA1>CA3>DG. The time-courses of the L-glutamate fluxes at CA1 and DG were biphasic, while that at CA3 decreased monotonously. The KCl-stimulated release of L-glutamate in the presence of the DL-TBOA uptake inhibitor was imaged. While no noticeable change was observed in the absence of DL-TBOA, L-glutamate fluxes in the presence of the inhibitor increased in the order CA1>CA3>DG, reflecting the effect of uptake processes. The present approach suppressed diffusional blur of the glutamate signal and improved the temporal resolution as compared with the BSA-HRP membrane method described earlier.

Although four-rooted mandibular first molars have been observed on a few occasions in the literature, to the best of our knowledge, four-rooted second molars have not been reported. Here, we describe a mandibular second molar with four roots and canals: two mesial and two distal. Mesial roots were separated in the cervical one-third near the cervical margin, while distal roots were divided at a lower level in the middle one-third of the root. We discuss the possibility of different root and canal variations of the mandibular second molar from a developmental point of view.

Objective: The purpose of this study was to investigate cusp size variability in the human permanent maxillary first and second molars, with particular reference to the hypocone., Design: Data were obtained from dental casts collected during a longitudinal growth study of Australian Aboriginals (148 males and 119 females), living at Yuendumu in Australia. Categorical data described the expression of the hypocone and quantitative data described the areas of the molar cusps, mesiodistal and buccolingual crown diameters, and overall crown areas. Several hypotheses relating to cuspal variation within and between M1 and M2 were tested using Chi-square tests, t-tests and ANOVA., Results: The pattern of relative variation in maxillary molar cusp areas reflected the ontogeny of crown development, with earlier-forming cusps showing less variation than later-forming cusps. Sex differences in hypocone area were larger in M2s than in M1s and there was evidence of an interaction during development between the protocone and the hypocone in M2s. Those M2s with larger hypocones displayed larger crown areas and the hypocone of M1s tended to be smaller in individuals who displayed hypocone reduction in their M2s., Conclusions: Our findings are consistent with the view that phenotypic variability within maxillary molar crowns is generated by dynamic interactions between developing cusps that form at different times and grow at different rates for different durations. Observed variation in cusp areas and hypocone expression between the maxillary M1 and M2 can also be explained in terms of differences in timing and duration of development of these teeth.

The main purpose of this study was to investigate the root and canal morphology of Sri Lankan mandibular molars and to determine the affinities of these morphological variations to those of people of European and Asian origin. Two hundred mandibular first and second molars were examined. The number of roots and the prevalence of C-shaped (gutter-shaped) roots in mandibular second molars were recorded. Root canal morphology was studied using a clearing technique. The examination of root canal systems of the teeth was based on Vertucci's classification. Among mandibular first molars, only 3% had three roots. Mesial roots of the first molar typically presented with two canals and two apical foramina with type IV, V, or VI canal configuration. Most distal roots of the first molar presented with a type I canal configuration. The remainder were distributed mainly between types III and V. Among mandibular second molars, 6% had single C-shaped roots, while C-shaped canals were found in only 2%. The majority of mesial roots of the second molar showed one or two canals, with one apical foramen with type I, II, or III canal morphology. In addition, the distal root commonly showed type I canal configuration. Intercanal communications and lateral canals were more frequently seen in the first molar than in the second. The root canal morphology in mandibular molars varies among population groups. Mandibular root and canal morphology of Sri Lankan people has closer affinities with that of people of European than of East Asian origin.

A new method for estimating skeletal age at death from the morphology of the auricular surface of the ilium is presented. It uses a multiple regression analysis with dummy variables, and is based on the examination of 700 modern Japanese skeletal remains with age records. The observer using this method needs only to check for the presence or absence of nine (for a male) or seven (for a female) features on the auricular surface and to select the parameter estimates of each feature, calculated by multiple regression analysis with dummy variables. The observer can obtain an estimated age from the sum of parameter estimates. It is shown that a fine granular texture of the auricular surface is typical of younger individuals, whereas a heavily porous texture is characteristic of older individuals, and that both of these features are very useful for estimating age. Our method is shown here to be more accurate than other methods, especially in the older age ranges. Since the auricular surface allows more expedient observations than other parts of the skeleton, this new method can be expected to improve the overall accuracy of estimating skeletal age at death.

Size relationships among crown units of permanent mandibular molars were investigated in two Sahul-Pacific samples: Aboriginal Australians (Yuendumu) and Papua New Guinea Highlanders (Wabag). Measurements of first, second, and third molars (M1, M2, and M3), including overall mesiodistal and buccolingual diameters as well as the mesiodistal and buccolingual diameters of the trigonid and talonid, were obtained from dental casts using a sliding caliper. Molar reduction was noted in talonid dimensions within both samples, but the trigonid mesiodistal diameter was not reduced in M2 or M3 compared with M1, indicating that the later-developing crown unit (talonid) was more reduced than the early-developing unit (trigonid). M2 was most reduced in size mesiodistally of the three molars, but its buccolingual diameter was not reduced. M3 was the most reduced tooth in trigonid buccolingual diameter. The percentage sexual dimorphism values were greater for the size of the talonid than for the trigonid, indicating that male values exceeded those for females by a greater amount in the later-developing crown unit. Crown dimensions were larger generally in the Aboriginal Australians from Yuendumu than in the Papua New Guinea Highlanders from Wabag, with differences being more evident in M2 and M3 than M1, especially in talonid dimensions. The trigonid, which develops early both phylogenetically and ontogenetically, tended to be relatively stable in size, whereas the later-forming talonid displayed size reduction when comparisons were made both within and between groups., (Copyright 2005 Wiley-Liss, Inc)

Dental crowding is defined as a discrepancy between tooth size and jaw size that results in a misalignment of the tooth row. Proposed reasons for crowding include excessively large teeth, small jaws, and a combination of both. Nevertheless, the parameters that would allow the prediction of crowding have not been identified. This study compared the shape of crowded and uncrowded dental arches, matched for size and sex. The application of elliptical Fourier functions (EFFs) provided an accurate numeric description of the dental arch form. Dental casts from the Nihon University School of Dentistry at Matsudo, Chiba, Japan, were studied. Group I, the control group, consisted of 118 dental cast pairs (49 female, 69 male, aged 20.40 +/- 1.68 years [mean +/- SD]) with little or no crowding. Group II, which exhibited crowding, consisted of 78 dental cast pairs (64 female, 14 male, aged 19.67 +/- 4.95 years). From photographs, a set of 24 homologous points describing the tooth row was identified. These points were then fitted with EFFs. Each maxillary and mandibular outline was subsequently standardized for size by scaling the bounded area to a constant 10,000 mm(2). These "shape only" data were used to assess differences between arches in the 2 groups. By multivariate analysis of variance, statistically significant shape differences between groups I and II were obtained for both arches. Patients with crowding exhibited more variability than did the controls. This variability was illustrated with canonical axes derived from discriminant function analysis.

Hand washing is an indispensable procedure for surgical nurses. Although scrubbing up with a brush is preferable to prevent infections, it is not clear how irritating to the skin scrubbing with a brush is compared with hand washing without a brush. TEWL, high frequency conductance and pH were measured on the hand skin of the same group of nurses before and after daily hand washing for 11 days in different seasons, which were chosen as favourable and unfavourable periods for the condition of hand skin, namely the early summer and autumn. Additionally, we compared the antimicrobial effects on the skin of scrubbing up, using a palm stamp method. TEWL showed significantly higher values with brush washing than with simple hand washing only in the autumn. There was no significant difference in the measurement of high frequency conductance, pH or in the antimicrobial effects between the two washing techniques. Results showed the deleterious effects on the skin of hand washing, particularly that of using a brush in the cold season.

The aims of this study were to investigate gender differences in frontal sinus morphology and to estimate differences between Fijian and Western Samoan populations. Cephalograms of 118 Fijians (59 male, 59 female), 80 W. Samoans (33 male, 47 female) and 89 Japanese (60 male, 29 female) were used in this study. The thickness of the frontal sinus and the convexity of glabella in males were found to be larger than those of females in each population. The angle of Sg-N-G in the Fijians was larger than that of the Western Samoans and Japanese. In order to compare the frontal sinus morphology among populations, Mahalanobis' generalized distances were calculated on the basis of the five distance diameters. The results indicate that gender is separated by the first axis which indicates the overall size. Japanese samples were separated from South Pacific samples by the second axis which indicates the shape factor. In populational discrimination, there was a higher percentage of correct discriminations of the females of the males. In conclusion, gender difference was recognized in the size of the frontal sinus, and the populational differences were shown in the shape factor between Melanesian and Polynesian populations, and also between South Pacific and Japanese populations.

An anthropological survey was conducted in Fiji in 1994 and 1995 to study dental arch form, craniofacial morphology, and bite force of Fijians. Measurements were obtained from dental casts, cephalograms, and thin pressure-sensitive sheets (Dental Prescale®) for bite force analysis. Results were compared with those of Japanese. In every direction, the size of the dental arch in Fijians was larger than in Japanese. Fijians displayed longer palates, longer mandibles, and bimaxillary protrusion. There was no significant difference in upper and lower facial heights. FH to lower incisor angle in Fijians was significantly larger than in Japanese. Fijians were characterized by a small palatal plane angle, occlusal plane angle and mandibular plane angle, and were thus brachyfacial. The Japanese tended to be more dolichofacial. The distances from the Cd line to the pterygoid muscles, masseter muscles, and teeth in Fijians were significantly longer than in Japanese. Occlusal contact areas of Fijians were also greater than those of Japanese. The results indicate that the masticatory muscles and craniofacial morphologies supporting them would be better integrated in Fijians than in Japanese. Am. J. Hum. Biol. 10:63-72, 1998. © 1998 Wiley-Liss, Inc., (Copyright © 1998 Wiley-Liss, Inc.)

The purpose of this study was to provide information about arch shape variations among South Pacific populations. The application of Fourier transforms, Y(phi i) = ao/2 + sigma (aicos phi i + bisin phi i) was used to separate two components of variation; size and shape. Dental arch size can be described by one coefficient (ao), while the shape can be summarized by the first three harmonics (amp1-3) in the Fourier series. The materials used in this study were dental casts of South Pacific populations (Fiji, Western Samoa and Kiribati), Australian Aboriginals and Japanese. Fijians, Western Samoans and Kiribati people have larger upper and lower dental arches than that of Japanese. These populations were separated by the arch size and first Fourier amplitudes which showed the arch depth/width ratio. The Fijian upper and lower dental arches were significantly larger than those found in other populations and was characterized by a wide posterior arch breadth. The Western Samoan and Kiribati arch shape was more similar to the Japanese arch shape than the Fijian. Distribution patterns of arch shape characteristics in these populations showed the same tendencies in the upper and lower arches.

A study was done to clarify the attachment position of the superficial masseter muscle and its relationship with craniofacial morphology in dentate and edentulous subjects. Data were obtained from lateral cephalometric radiographs of a total of 39 cadavers in which the superficial masseter muscle had been defined with colloidal barium. Principal component analysis provided evidence that the lower masseter muscle width was associated with the size of the ramus, and related to the position of the anterior margin of the muscle. Linear discriminant function data suggested that ramus width, coronoid height and the distance between the anterior margin of the masseter muscle and the mandibular notch contributed most to the observed difference between dentate and edentulous subjects. The derived function correctly assigned 100% of dentate and 95% of edentulous subjects. The results of this study indicated that a reduction of masticatory function was associated with the position of the anterior border of the masseter muscle insertion and also with differences in ramus dimension, the most significant of which were differences in the coronoid process and gonial angle. In general, age was not a significant determinant of variation in superficial masseter muscle dimensions or orientation.

A study was conducted to evaluate the relationship between morphological characteristics of vertical sections of the mandibular body and dentopfacial morphology. Cortical bone thickness, tooth inclination and bone inclination of the mandible were investigated. Among skeletal components, ANSMe distance was associated with the buccal cortical bone thickness of the P2 (second premolar) section. Gonial angle, SN to mandibular angle, and palatal to mandibular angle were negatively correlated with the buccal cortical bone thickness of P2 and M1 (first molar) sections. SNA and SNB which indicated the protrusion of the upper and lower jaws were positively correlated with the buccal cortical bone thickness of the M1 section. Among denture components, lower and upper incisor positions showed a significant negative correlation with the buccal cortical bone thickness of the P2 section. The interincisal angle was associated with the basal cortical bone thickness of the M2 (second molar) section. In summary, there were significant and complex relationships between the structures of the mandibular body and maxillofacial morphology. Facial types which relate to masticatory function are associated with the cortical bone thickness of the mandibular body.

A study was conducted to assess the measurement accuracy of a laser three-dimensional measurement system for measuring facial profile and to investigate the changes in lower facial morphology caused by experimental protrusion of the upper incisors, and also to examine the relationship between the changes in lip form and lip thickness. The study subjects were 24 Japanese male dental students attending Nihon University School of Dentistry at Matsudo, who had normal overbite, overjet, and normal occlusion, and a good facial profile. The mean age was 23.2 years with a range of 21.5 to 25.8 years. Three-dimensional measurements obtained by a computerized 3D laser scanning system were used to evaluate facial morphology. The measurement error of this system was less than 0.5 mm in any three-dimensional linear measurements. The stability and reproducibility of the recording procedure were evaluated. The changes in facial morphology caused by orthodontic treatment and orthognathic surgery were visualized in any direction by this three-dimensional graphic system. Lip thickness was not associated with changes in lip form. However, a relationship between the right and left corners of lip and lip thickness was noted. With regard to the ratio of changes in hard tissue and lips, the value of the original position for a 4 mm protrusion was not the same as that for a 4-8 mm protrusion. Also, the correlation of the changes in both groups was very low. The changes in lip thickness were associated with changes in stomion position, which in turn were related to the vertical change in the upper lip.

Teeth extracted from Japanese male cadavers were analyzed from the morphogenetic point of view. Variables were buccolingual crown diameter, mesiodistal crown diameter, crown height, root length and total length. Each dimension was analyzed separately by means of principal component analysis with varimax rotation. Components extracted from crown dimensions and total length showed 3 or 4 of 5 underlying components for morphogenetic field, anterior group, molar, premolar, canine and incisor. However, for crown height and root length, the components were less distinct.

The purpose of this study is to evaluate the relationships between the sectional forms of the mandible and the craniofacial morphology. Vertical sections were made at the symphysis (SY) and at the second molar region (M2R). Materials were dried human skulls which were measured in three dimensional co-ordinate system. The correlation matrix of 24 measurements was examined in the male and the female. The difference of these measurements between the low angle group and the high angle group of gonial angle was also examined. Results obtained were as follows: 1. Gonial angle was negatively correlated with the height, width, breadth of ramus and the breadth of second molars. SY form was related to the facial height and size of the mandible. On the other hand, M2R form was related to the height, width and breadth of ramus. 2. The differences of measurements between the low angle group and the high angle group of gonial angle were as follows: 1) The ramal height, ramal width, bicondylar width and breadth of second molars in the low angle group were significantly larger than those in the high angle group. 2) The measurements of SY in the high angle group and the low angle group showed no significant difference. 3) The height and area of M2R in the low angle group were significantly larger than those in the high angle group. This study demonstrated that SY form might relate to vertical factors of the face (facial height), the size of mandible and the types of occlusions. On the other hand, M2R form being nearer to the attachment of masseter and medial pterygoid muscles than SY was related to the form of ramus and the gonial angle.

The frequency of occurrence of anomalous cusps or tubercles on human upper first molars was investigated in seven racial populations using moiré contourography, which permits the three-dimensional measurement of minute cusps. Tubercles on the mesial marginal ridge were more frequently found in Mongoloid populations (Japanese and Eskimo) than in others. The frequency of the protoconule was high in Eskimos and Negroids (Bantu and San). The lingual paracone tubercle (mesial cusp) showed a particularly high frequency in Australian aborigines. The metaconule was rare or absent in all of the populations. Caucasoid groups (Dutch White and Asiatic Indian) showed generally low frequencies of all these abnormal tubercles, especially the distal accessory cusp (C5). Racial differences in the frequencies of occurrence may offer a key to understanding the adaptive significance of these traits and human microevolution. Confusion in nomenclature for upper molar tubercles is also discussed.

The three-dimensional measurement of the parietal curvature in Japanese was accomplished with the use of moiré contourography and the sexual dimorphism was observed in it. Principal component analysis was also carried out and 4 important features of the shape of this bone were abstracted. Those were the degree of the curvature as a whole, lateral swellings, bilateral difference and posterior swelling.

Moiré photographs of the occlusal surface of first molars of Japanese children were taken by means of a specially designed moiré contourograph apparatus. They were then used for three-dimensional measurements. The heights of 4 cusps and some other points were measured by counting contour lines. Distances and angles between them were also measured. Sex differences of these measurements are found mainly around the metacone and hypocone. There is no clear correlation of the four cuspidal heights to the distances between them.