Depressive symptoms predict smoking cessation in a 20-year longitudinal study of adult twins.

Depression has been suggested to hinder smoking cessation, especially when co-occurring with nicotine dependence. The study aimed to examine the longitudinal association of depressive symptoms with smoking cessation among daily smokers. The study utilized adult Finnish twin cohort where 1438 daily smokers (mean age: 38.3, range: 33-45) in 1990 were re-examined for their smoking status in 2011. We assessed baseline depressive symptoms with the Beck Depression Inventory, and the self-reported smoking status at follow-up. The methods included multinomial logistic regression and time to event analyses, adjusted for multiple covariates (age, sex, marital status, social class, heavy drinking occasions, and health status) and smoking heaviness at baseline assessed by cigarettes per day (CPD). Additionally, within-twin-pair analyses were conducted. Results indicated that moderate/severe depressive symptoms at baseline were associated with a lower likelihood of smoking cessation two decades later. Adjusting for covariates, those with moderate/severe depressive symptoms (vs. no/minimal depressive symptoms) had 46% lower likelihood of quitting (relative risk ratio, RRR = 0.54, 95% CI: 0.30-0.96). After including CPD, the association of depressive symptoms with smoking cessation attenuated modestly (RRR = 0.62, 95% CI: 0.34-1.12). Further, time to event analysis for quitting year since baseline yielded similar findings. In the within-pair analysis, depressive symptoms were not associated with quitting smoking. The results suggest that reporting more depressive symptoms is associated with a lower likelihood of smoking cessation during a 20-year period. The baseline amount of smoking and familial factors partly explain the observed association. Smoking cessation programs should monitor depressive symptoms.

Weight concerns as a predictor of smoking cessation according to nicotine dependence: A population-based study.

BACKGROUND: Nicotine-dependent smokers find it difficult to quit smoking. Additionally, smoking-specific weight concerns may affect smoking cessation although the evidence is controversial. We investigated whether smoking-specific weight concerns predict the probability of cessation and, if so, whether the effect varies according to the level of nicotine dependence. METHODS: The study was conducted with a population-based sample of 355 adult daily smokers who participated in the baseline examination in 2007 and in the 2014 follow-up. Baseline nicotine dependence was classified as low or high (Fagerström Test for Nicotine Dependence; 0-3 vs. 4-10 points). Within these groups, we examined whether baseline weight concerns predict smoking status (daily, occasional, ex-smoker) at follow-up by using multinomial logistic regression with adjustment for multiple covariates. RESULTS: Among low-dependent participants at baseline, 28.5% had quit smoking, while among highly dependent participants 26.1% had quit smoking. The interaction between weight concerns and nicotine dependence on follow-up smoking status was significant. Among participants with low nicotine dependence per the fully adjusted model, greater weight concerns predicted a lower likelihood of both smoking cessation (relative risk ratio 0.93 [95% CI 0.87-1.00]) and smoking reduction to occasional occurrence (0.89 [95% CI 0.81-0.98]). Weight concerns were not associated with follow-up smoking status among participants with high nicotine dependence. CONCLUSIONS: Weight concerns are associated with a smaller likelihood of quitting among smokers with low nicotine dependence. Weight concerns should be addressed in smoking cessation interventions, especially with smokers who have low nicotine dependence.

Smoking status and abdominal obesity among normal- and overweight/obese adults: Population-based FINRISK study.

Several studies have reported direct associations of smoking with body mass index (BMI) and abdominal obesity. However, the interplay between them is poorly understood. Our first aim was to investigate the interaction between smoking status and BMI on abdominal obesity (waist circumference, WC). Our second aim was to examine how the association of smoking status with WC varies among normal and overweight/obese men and women. We examined 5833 participants from the National FINRISK 2007 Study. The interactions between smoking and BMI on WC were analyzed. Participants were categorized into eight groups according to BMI (normal weight vs. overweight/obese) and smoking status (never smoker, ex-smoker, occasional/light/moderate daily smoker, heavy daily smoker). The associations between each BMI/smoking status -group and WC were analyzed by multiple regressions, the normal-weight never smokers as the reference group. The smoking status by BMI-interaction on WC was significant for women, but not for men. Among the overweight/obese women, ex-smokers (ß = 2.73; 1.99, 3.46) and heavy daily smokers (ß = 4.90; 3.35, 6.44) had the highest estimates for WC when adjusted for age, BMI, alcohol consumption and physical activity. In comparison to never smoking overweight/obese women, the ß-coefficients of ex-smokers and heavy daily smokers were significantly higher. Among men and normal weight women the ß -coefficients did not significantly differ by smoking status. An interaction between smoking status and BMI on abdominal obesity was observed in women: overweight/obese heavy daily smokers were particularly vulnerable for abdominal obesity. This risk group should be targeted for cardiovascular disease prevention.

Factors influencing dental students' specialty choice: a survey of ten graduating classes at one institution.

The aim of this study was to survey ten graduating classes at Harvard School of Dental Medicine regarding students' specialty choice and factors influencing that choice. Students were surveyed once in 2008 (for the Classes of 2007-11) and again in 2013 (for the Classes of 2012-16). A prior article reported results regarding students' interest in and experiences with prosthodontics; this article presents results regarding their interest in all dental specialties and factors influencing those interests. Of a total 176 students in the Classes of 2012-16, 143 responded to the survey, for a response rate of 81%, compared to a 95% response rate (167 of total 176 students) for the Classes of 2007-11. The results showed that orthodontics was the most popular specialty choice, followed by oral and maxillofacial surgery. From the 2008 to the 2013 survey groups, there was an increase in the percentages of students planning to pursue oral and maxillofacial surgery, pediatric dentistry, and postdoctoral general dentistry. The educational debt these students expected to accrue by graduation also increased. The largest percentage of students chose "enjoyment of providing the specialty service" as the factor most influencing their specialty choice. "Prior dental school experience" and "faculty influence" were greater influences for students pursuing specialties than those pursuing postdoctoral general dentistry. Increased interest in particular disciplines may be driven by high debt burdens students face upon graduation. Factors related to mentoring especially influenced students pursuing specialties, demonstrating the importance of student experiences outside direct patient care for exposure to the work of specialists beyond the scope of predoctoral training. This finding suggests that dental schools should increase mentoring efforts to help students make career decisions based not on financial burden but rather on personal interest in the specialty, which is likely to have a more satisfying result for them in the long run.

Dental students' perceptions of and experiences with prosthodontics: ten graduating classes at one institution.

It is important for members of the dental specialties to understand what motivates students to enter the specialty in order to ensure its continuing development and ability to meet patient needs. The aim of this study was to compare ten graduating classes at Harvard School of Dental Medicine (HSDM) regarding students' experiences with and perceptions of prosthodontics and factors influencing those interested in pursuing prosthodontics as a specialty. In 2013, HSDM students in the classes of 2012-16 were surveyed, achieving a response rate of 81%. Survey questions sought information regarding specialty choice, factors influencing the choice, student experiences with prosthodontics, and student perceptions of the dental disciplines. Responses were compared to those from a prior study of the HSDM classes of 2007-11. The responses showed a decrease in negative student experiences with prosthodontics. The students regarded prosthodontics highly for its impact on patient quality of life; however, students interested in pursuing prosthodontics as a specialty decreased. All students said provider enjoyment was most important in choice of specialty. Cost of program, patient type, and program location were factors that especially influenced students interested in prosthodontics. The improved student experiences with and perspectives on prosthodontics may be a result of a curriculum change that led to more prosthodontics procedures and case completions by students. The fall in students interested in prosthodontics may have resulted from prosthodontic faculty transitions that occurred when the survey was conducted, as well as large debt burdens in spite of the fact that prosthodontists' earnings are among the highest in dentistry. Faculty must educate and mentor students about the realities of the profession, provide positive learning experiences in the field, and encourage students who enjoy prosthodontics to pursue specialty training.

Associations of Weight Concerns With Self-Efficacy and Motivation to Quit Smoking: A Population-Based Study Among Finnish Daily Smokers.

INTRODUCTION: Concerns about weight gain occurring after smoking cessation may affect motivation and self-efficacy towards quitting smoking. We examined associations of smoking-specific weight concerns with smoking cessation motivation and self-efficacy in a population-based cross-sectional sample of daily smokers. METHODS: Six-hundred biochemically verified (blood cotinine) current daily smokers comprising 318 men and 282 women aged 25-74 years, were studied as part of the National FINRISK (Finnish Population Survey on Risk Factors on Chronic, Noncommunicable Diseases) study and its DIetary, Lifestyle and Genetic factors in the development of Obesity and Metabolic syndrome (DILGOM) sub-study that was conducted in Finland in 2007. Self-reported scales were used to assess weight concerns, motivation and self-efficacy regarding the cessation of smoking. Multiple regression analyses of concerns about weight in relation to motivation and self-efficacy were conducted with adjustments for sex, age (years), body mass index (BMI, [kg/m(2)]), physical activity (times per week), and further controlled for nicotine dependence (Fagerström Test for Nicotine Dependence). RESULTS: Higher levels of weight concerns were associated with lower self-efficacy (ß = -0.07, p < .001) after adjusting for sex and age. The association remained after additional adjustment for BMI and physical activity (ß = -0.07, p < .001). After further controlling for nicotine dependence the association became weaker but remained significant (ß = -0.04, p = .02). There were no statistically significant associations between concerns about weight and motivation for smoking cessation (ß = 0.02, p = 0.16). CONCLUSIONS: These cross-sectional population-based data do not support earlier findings that suggest that smokers with high levels of weight concerns are less motivated to quit smoking. Our data suggest that daily smokers who are highly concerned about weight may have lower self-efficacy for cessation of smoking.

Early performance in a humanistic medicine course as a predictor of dental students' later clinical performance.

The purpose of this study was to test the hypothesis that dental students' early ability to demonstrate a humanistic approach with patients is associated with later clinical performance. A first-year humanistic medicine course, Patient Doctor I (PDI), at Harvard School of Dental Medicine combines training in conducting the medical interview with human values, placing a high value on strengthening relationships with patients and emphasizing empowerment, respect, and strong communication skills. Retrospective data were collected in the following domains: PDI course evaluations, admissions information, National Board Dental Examination Parts I and II scores, and Promotions Committee and faculty evaluation scores for hand skills and humanistic and interactive patient-student skills. Planned linear contrasts comparisons were performed for each clinical outcome variable. Tests to support the a priori hypothesis of linear relationships between PDI evaluation ratings and clinical performance, defined as hand skills and humanistic and interactive patient-student skills scores, were significant, both at p=0.03. This study demonstrated the feasibility of measuring dental students' humanistic qualities during the first year. Humanistic qualities (PDI performance) during the first year were found to be associated with clinical performance in the third year of dental school.

Implementation of tobacco use cessation counseling among oral health professionals in Finland.

OBJECTIVES: Clinical guidelines for tobacco use cessation (TUC) counseling recommend that healthcare professionals should provide brief tobacco counseling for all tobacco users. Widespread implementation of these guidelines seems to be insufficient. To enhance adherence to TUC counseling guidelines, it is essential to identify provider behaviors related to a successful implementation. This study aims to assess adherence to TUC counseling guidelines and factors that are associated with counseling behaviors. METHODS: A 41-item questionnaire relevant to the implementation of TUC counseling guidelines among healthcare professionals was administered. This questionnaire included items used to evaluate TUC counseling behaviors as well Theoretical Domains Framework (TDF)-based behavior change items. Of the 95 oral health professionals invited from 34 community dental clinics in Finland, 73 professionals (76.8 percent) participated. The TDF factors and their associations to TUC counseling behaviors were analyzed using correlations and logistic regression analyses. RESULTS: Adherence to TUC counseling guidelines, especially for providing advice to quit, assisting in quitting and arranging follow-up services, were low. In addition, only 15.1 percent of the providers reported asking about tobacco use and 8.2 percent assessed interest in quitting among the majority (>75 percent) of their patients. Of the behavior change domains, "Memory, Attention and Decision Processes" and "Professional Role and Identity" were found to be significantly associated with TUC counseling behavior among oral health professionals. CONCLUSIONS: Regarding the adherence to TUC counseling guidelines, there is room for improvement. The identified TDF factors related to TUC behaviors provide an avenue for targeted interventions to improve guideline implementation.

Women's oral health: why sex and gender matter.

This article examines the differences and interaction between sex and gender, and how they affect women's oral and general health. The authors provide a definition of women's health, and examples of how this definition can be used to describe various oral health conditions and diseases in women. The article reviews the research on sex and gender and provides examples of their interactions. Examples of oral diseases that affect primarily women are reviewed. Advice for clinicians on the diagnosis, management, and prevention of these conditions is provided.

Impact of educational intervention on implementation of tobacco counselling among oral health professionals: a cluster-randomized community trial.

OBJECTIVES: Tobacco use adversely affects oral health. Clinical guidelines recommend that oral health professionals promote tobacco abstinence and provide patients who use tobacco with brief tobacco use cessation counselling. Research shows that these guidelines are seldom implemented successfully. This study aimed to evaluate two interventions to enhance tobacco use prevention and cessation (TUPAC) counselling among oral health professionals in Finland. METHODS: We used a cluster-randomized community trial to test educational and fee-for-service interventions in enhancing TUPAC counselling among a sample of dentists (n=73) and dental hygienists (n=22) in Finland. Educational intervention consisted of 1 day of training, including lectures, interactive sessions, multimedia demonstrations and a role play session with standard patient cases. Fee-for-service intervention consisted of monetary compensation for providing tobacco use prevention or cessation counselling. TUPAC counselling procedures provided were reported and measured using an electronic dental records system. In data analysis, intent-to-treat principles were followed at both individual and cluster levels. Descriptive analysis included chi-square and t-tests. A general linear model for repeated measures was used to compare the outcome measures by intervention group. RESULTS: Of 95 providers, 73 participated (76.8%). In preventive counselling, there was no statistically significant time effect or group-by-time interaction. In cessation counselling, statistically significant group-by-time interaction was found after a 6-month follow-up (F=2.31; P=0.007), indicating that counselling activity increased significantly in intervention groups. On average, dental hygienists showed greater activity in tobacco prevention (F=12.13; P=0.001) and cessation counselling (F=30.19; P<0.001) than did dentists. In addition, cessation counselling showed a statistically significant provider-by-group-by-time interaction (F=5.95; P<0.001), indicating that interventions to enhance cessation counselling were more effective among dental hygienists. CONCLUSIONS: Educational intervention yielded positive short-term effects on cessation counselling, but not on preventive counselling. Adding a fee-for-service to education failed to significantly improve TUPAC counselling performance. Other approaches than monetary incentives may be needed to enhance the effectiveness of educational intervention. Further studies with focus on how to achieve long-term changes in TUPAC counselling activity among oral health professionals are needed.

Challenges in global improvement of oral cancer outcomes: findings from rural Northern India.

BACKGROUND: In India, 72% of the population resides in rural areas and 30-40% of cancers are found in the oral cavity. The majority of Haryana residents live in villages where inadequate medical facilities, no proper primary care infrastructure or cancer screening tools and high levels of illiteracy all contribute to poor oral cancer (OC) outcomes. In this challenging environment, the objective of this study was to assess the association between various risk factors for OC among referrals for suscipious lesions and to design and pilot test a collaborative community-based effort to identify suspicious lesions for OC. SETTING: Community-based cross sectional OC screening. PARTICIPANTS: With help from the Department of Health (DOH), Haryana and the local communities, we visited three villages and recruited 761 participants of ages 45-95 years. PARTICIPANTS received a visual oral cancer examination and were interviewed about their dental/medical history and personal habits. Pregnant women, children and males/females below 45 years old with history of OC were excluded. MAIN OUTCOME: Presence of a suspicious oral lesion. RESULTS: Out of 761 participants, 42 (5.5%) were referred to a local dentist for follow-up of suspicious lesions. Males were referred more than females. The referral group had more bidi and hookah smokers than non smokers as compared to non referral group. The logistic regression analysis revealed that smoking bidi and hookah (OR = 3.06 and 4.42) were statistically significant predictors for suspicious lesions. CONCLUSIONS: Tobacco use of various forms in rural, northern India was found to be quite high and a main risk factor for suspicious lesions. The influence of both the DOH and community participation was crucial in motivating people to seek care for OC.

Assessing early performance in the patient-doctor relationship in dental education.

In addition to current admissions criteria, the assessment of qualities related to humanistic medicine may help predict clinical and academic performance in dental education. The objective of this feasibility study was to develop and assess the reliability of a coding scheme to quantify and rate qualitative formative narratives describing individual student performance in a medical interview course that utilizes principles of humanistic medicine. A mixed method, using focus groups and individual interviews, was used to develop a coding strategy. Three coders retrospectively rated 209 formative narratives evaluating first-year students at the Harvard School of Dental Medicine to determine high and low performance in this course. Interrater reliability was tested. The focus groups yielded the use of superlatives to identify high performance, with their absence indicating low performance. This study found a high level of calibration among independent coders (Cronbach's alpha 0.75). Twenty-four (11.5 percent) of the narrative evaluations were coded as "high performers" and seven (3.3 percent) as "low performers." The results demonstrate the feasibility of quantifying narrative evaluations to determine high and low performance in a patient-centered course for dental students. It may be that humanistic qualities taught in a patient-centered medical interview course are more significant competencies than previously thought.

Coxa morphologically adapted to large egg in aepyornithid species compared with various palaeognaths.

The coxa of palaeognaths including extinct aepyornithid species was compared by means of osteology, computed tomography (CT) imaging and macroscopic anatomy. The pre-acetabular area of the ilium was proportionally much larger in width and height in aepyornithid species than in other extant palaeognaths. The post-acetabular area of the ilium, ischium and pubis was relatively short and bilaterally extended in aepyornithid species. Although the Aepyornis species might have produced egg with a major axis exceeding 300 mm in major axis, the short post-acetabular coxa and widely opened ischium and pubis would not have been able to stably hold the eggs in the posterior space of the pelvic cavity unlike the situation in the ostrich. As aepyornithid species resembled the kiwi in measurement ratios of length and width in the pre-acetabular area, a functional-morphological model of the coxa in the aepyornithid species can be proposed based on that of the kiwi. From our data, we suggest that the extinct species of Aepyornis and Mullerornis species effectively used the anterior space of the pelvic cavity to support their extraordinary large egg.

Assessing implementation difficulties in tobacco use prevention and cessation counselling among dental providers.

BACKGROUND: Tobacco use adversely affects oral health. Clinical guidelines recommend that dental providers promote tobacco abstinence and provide patients who use tobacco with brief tobacco use cessation counselling. Research shows that these guidelines are seldom implemented, however. To improve guideline adherence and to develop effective interventions, it is essential to understand provider behaviour and challenges to implementation. This study aimed to develop a theoretically informed measure for assessing among dental providers implementation difficulties related to tobacco use prevention and cessation (TUPAC) counselling guidelines, to evaluate those difficulties among a sample of dental providers, and to investigate a possible underlying structure of applied theoretical domains. METHODS: A 35-item questionnaire was developed based on key theoretical domains relevant to the implementation behaviours of healthcare providers. Specific items were drawn mostly from the literature on TUPAC counselling studies of healthcare providers. The data were collected from dentists (n = 73) and dental hygienists (n = 22) in 36 dental clinics in Finland using a web-based survey. Of 95 providers, 73 participated (76.8%). We used Cronbach's alpha to ascertain the internal consistency of the questionnaire. Mean domain scores were calculated to assess different aspects of implementation difficulties and exploratory factor analysis to assess the theoretical domain structure. The authors agreed on the labels assigned to the factors on the basis of their component domains and the broader behavioural and theoretical literature. RESULTS: Internal consistency values for theoretical domains varied from 0.50 ('emotion') to 0.71 ('environmental context and resources'). The domain environmental context and resources had the lowest mean score (21.3%; 95% confidence interval [CI], 17.2 to 25.4) and was identified as a potential implementation difficulty. The domain emotion provided the highest mean score (60%; 95% CI, 55.0 to 65.0). Three factors were extracted that explain 70.8% of the variance: motivation (47.6% of variance, α = 0.86), capability (13.3% of variance, α = 0.83), and opportunity (10.0% of variance, α = 0.71). CONCLUSIONS: This study demonstrated a theoretically informed approach to identifying possible implementation difficulties in TUPAC counselling among dental providers. This approach provides a method for moving from diagnosing implementation difficulties to designing and evaluating interventions.

The effect of impression volume and double-arch trays on the registration of maximum intercuspation.

STATEMENT OF PROBLEM: The type of double-arch trays used may affect occlusion. PURPOSE: The purpose of this study was to determine what effect, if any, double-arch tray design and impression material volume had on the registration of maximum intercuspation (MI). MATERIAL AND METHODS: Quadrant impressions were made on articulated fracture-resistant dental casts mounted in maximum intercuspation occlusion. Three types of sideless double-arch impression trays were used: First Bite with nylon webbing, Sultan's 3-Way with double crosshatch webbing, and Premium's 3-in-1 Tray with single crosshatch webbing. Vinyl polysiloxane impression material (Aquasil Ultra Rigid Fast Set) was distributed at 2 different volumes (5.4 ml and 8.3 ml), and 60 impressions were made (n=10). A weight of 1.2 kg was placed on the upper arm of an Artex articulator, ensuring complete closure. The impressions were allowed to polymerize for 5 minutes. After polymerization, specimens were placed on a light box, and a camera set at a fixed distance was used to capture the light transmission that was projected through the impression material. The camera transferred the information to an image analysis program (ImageJ). This system allowed the different amounts of light projected through the impression to be translated into a gray scale value (GSV), which was assigned a thickness value, in millimeters, of a specified occlusal contact area. To assess reliability of the experimental design, 10 control impressions were made by directly applying impression material onto the typodont. These were analyzed in the same manner as the impressions made with trays. A 2-way ANOVA comparing volume by tray type was used (alpha=.05). This was followed by a Tukey HSD test. RESULTS: There was no main effect for volume of impression material (P=.71). Tray type was significantly different (P<.001). Impressions made with Sultan trays were significantly less accurate than impressions made with First Bite or Premium impression trays. The Premium tray type had the highest mean (SD) GSV, 179.8 (8.1), significantly higher than First Bite (164.7 (19.8); P<.001) or Sultan (82.8 (7.4); P<.001) trays. CONCLUSIONS: This in vitro study demonstrated that certain trays hinder closure into MI, which may negatively affect the accuracy of record making.

Impact of Nicotine Replacement Therapy on post-cessation mood profile by pre-cessation depressive symptoms.

We evaluated the effects of Nicotine Replacement Therapy (NRT) on the Profile of Mood States (POMS), testing whether pre-cessation depressive symptoms modify NRT's effects on POMS. Out of 608 smokers attempting to quit with NRT, this secondary analysis included 242 participants abstinent for at least two weeks. We measured pre-cessation depressive symptoms with the Center for Epidemiological Studies Depression Scale. At 1, 7, and 14 post-cessation days we examined 6 self-reported POMS, i.e. feeling 'anxious', 'sad', 'confused', 'angry', 'energetic' and 'fatigue'. The results of the ANCOVA models suggested no NRT effects on feeling anxious, energetic or fatigue. We found that pre-cessation depression modified NRT effects in some specific mood states, such as depression by NRT- interaction effects on feeling confused and feeling angry. On average, the depressed participants in the placebo groups had the highest symptom scores. However, those depressed in NRT conditions did not have significantly higher symptom scores compared to the non-depressed groups. In treating those negative moods NRT may be particularly important for persons with depressive symptoms before cessation.

Smoking and suicidality among adolescent psychiatric patients.

PURPOSE: To investigate the relationship between smoking and suicidality among adolescent psychiatric patients in Finland. METHODS: Data from 157 patients (aged 12-17 years) admitted to inpatient psychiatric hospitalization between April 2001 and July 2002 were collected. Logistic regression analyses were used to examine the association between regular daily smoking and suicidality. The data were adjusted for several sociodemographic and clinical characteristics. RESULTS: The results showed over four-fold risk for definite and/or life-threatening suicide attempts among smoking adolescents in inpatient psychiatric facility compared with nonsmoking ones (OR 4.33, 95% CI 1.23-15.20). Also, the smoking adolescents had three times greater risk for occasional (OR 3.32, 95% CI 1.09-10.10) or frequent (OR 3.00, 95% CI 1.08-10.10) self-mutilation. Suicidality was more common among girls than boys and among those adolescents who suffered from depression. CONCLUSIONS: Among teens hospitalized for psychiatric illnesses, daily smoking was significantly related to suicide attempts and self-mutilation, even after controlling for several confounding factors, including psychiatric diagnosis.

Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles.

The masticatory muscles and their related structures of the skull were observed in the Indian gavial (Gavialis gangeticus), the false gavial (Tomistoma schlegelii), and the African slender-snouted crocodile (Mecistops cataphractus) to detail some morphological differences in comparison with the other crocodile species, and to compare and elucidate the functional strategy of themasticatory apparatus in these long-snouted species. The Musculus pterygoideus posterior was relatively smaller in the three species compared with many short-snouted crocodiles. It suggests that the masticatory power in fish-eating long-snouted species is not so high as in the short-snouted crocodiles, while the masticatory muscles were morphologically different among the three long-snouted species as follows. The M. pterygoideus posterior of the false gavial was extended in the lateral side of the lower jaw unlike the Indian gavial. The M. pseudotemporalis and the Fenestra supratemporalis were largely developed in the Indian gavial, however we suggest that the other two species possess the weak bundles in this muscle. The false gavial and the African slender-snouted crocodile have the pterygoid bone well-developed extending dorso-ventrally and it is suggested that the M. adductor mandibulae posterior attached to the pterygoid bone may be much larger than the Indian gavial. These data morphologically clarify the masticatory mechanism in the long-snouted crocodiles different from the short-snouted species, and demonstrate that the evolutional strategy to share the functional role in the masticatory muscles have been differently established between the Indian gavial and the other two species. We also obtained the morphological data in the fossil skull of the Machikane crocodile (Toyotamaphymeia machikanense) and concluded from the fossil characters that the considerable developments of the M.pterygoideus posterior and the M.pseudotemporalis in this species had not morphologically been consistent with both the Indian and false gavials.

Musculoskeletal system of the neck of the polar bear (Ursus maritimus) and the Malayan bear (Helarctos malayanus).

The gross anatomical study was undertaken in the musculoskeletal system of the neck of the polar bear, and the findings were compared with those of the Malayan bear. The Musculus splenius and the M. trapezius were well-developed in the polar bear. The long neck of the polar bear consisted mainly of the M. splenius with the M. biventer cervicis and the M. complexus lying tightly underneath. The cervical vertebrae possessed huge ventral tubercle in the ventral part of the transverse process in the polar bear. These morphological characteristics suggest that the polar bear may rotate and bend the skull and the long cervical vertebrae. We postulate that the polar bear has evolved the high-mobility long neck to adapt for swimming. Unlike the polar bear, the Malayan bear has not specialized in the neck structure.

MRI examination of the masticatory muscles in the gray wolf (Canis lupus), with special reference to the M. temporalis.

We examined the head of the gray wolf (Canis lupus) using MRI methods. Although the arising surface of the M. temporalis was not so enlarged in the frontal bone, the small frontal bone did not disturb the M. temporalis from occupying the lateral space of the frontal area in the gray wolf as in the domesticated dog. In the gray wolf, it is suggested that the M. temporalis may not be well-developed in terms of size of arising area, but in the thickness of running bundles. We suggest that the dog has changed the three-dimensional plan of the M. temporalis during the domestication and that the M. temporalis has developed a large arising surface in the frontal bone and lost the thickness of belly in the frontal area in accordance with the enlargement of the frontal bone and the increase in brain size.