Three-dimensional hard tissue palatal size and shape: a 10-year longitudinal evaluation in healthy adults

A 10-year longitudinal evaluation of the morphology (size and shape) of hard tissue palate was performed in 6 female and 6 male healthy adults (mean age at the second evaluation was 33 years, SD = 2.2). All subjects had a complete permanent dentition, including the second molars, and were free from respiratory problems. Palatal landmarks were digitized with a computerized 3D instrument, and their coordinates were used to derive a mathematical model of palatal form. Palatal shape (size-independent) was assessed by a fourth-grade polynomial in the sagittal and frontal plane projections. Palatal dimensions in the frontal and sagittal planes were computed and compared between the 2 evaluations by paired Student t tests. A great variability was observed, and no significant modifications in size were found (P > .05 for all variables). No variations in shape were observed. Sex had no significant effect for any variable (Student t for independent samples, P > .05). This study showed that in healthy subjects, hard tissue palatal morphology does not seem to change between the third and the fourth decades of life.     

Anchorage effect of various shape palatal osseointegrated implants: a finite element study

The purpose of this study was to compare the anchorage effects of different palatal osseointegrated implants using a finite element analysis. Three types of cylinder implants (simple implant, step implant, screw implant) were investigated. Three finite element models were constructed. Each consisted of two maxillary second premolars, their associated periodontal ligament (PDL) and alveolar bones, palatal bone, palatal implant, and a transpalatal arch. Another model without an implant was used for comparison. The horizontal force (mesial 5N, palatal 1N) was loaded at the buccal bracket of each second premolar, and the stress in the PDL, implant, and implant surrounding bone was calculated. The results showed that the palatal implant could significantly reduce von Mises stress in the PDL (maximum von Mises stress was reduced 24.3-27.7%). The von Mises stress magnitude in the PDL was almost same in the three models with implants. The stress in the implant surrounding bone was very low. These results suggested that the implant is a useful tool for increasing anchorage. Adding a step is useful to lower the stress in the implant and surrounding bone, but adding a screw to a cylinder implant had little advantage in increasing the anchorage effect.     

The effect of age and sex on facial mimicry: a three-dimensional study in healthy adults

To assess sex- and age-related characteristics in standardized facial movements, 40 healthy adults (20 men, 20 women; aged 20–50 years) performed seven standardized facial movements (maximum smile; free smile; “surprise” with closed mouth; “surprise” with open mouth; eye closure; right- and left-side eye closures). The three-dimensional coordinates of 21 soft tissue facial landmarks were recorded by a motion analyser, their movements computed, and asymmetry indices calculated. Within each movement, total facial mobility was independent from sex and age (analysis of variance, p > 0.05). Asymmetry indices of the eyes and mouth were similar in both sexes (p > 0.05). Age significantly influenced eye and mouth asymmetries of the right-side eye closure, and eye asymmetry of the surprise movement. On average, the asymmetry indices of the symmetric movements were always lower than 8%, and most did not deviate from the expected value of 0 (Student's t). Larger asymmetries were found for the asymmetric eye closures (eyes, up to 50%, p < 0.05; mouth, up to 30%, p < 0.05 only in the 20–30-year-old subjects). In conclusion, sex and age had a limited influence on total facial motion and asymmetry in normal adult men and women.     

Three-dimensional hard tissue palatal size and shape in Down syndrome subjects

The aim of the present study was to evaluate palatal morphology in Down syndrome (Ds) subjects, focusing on the effect of dental formula on the hard palate to assist clinicians when planning dental rehabilitation. Palatal landmarks were digitized with a three-dimensional (3D) computerized digitizer on the dental casts of 47 Ds subjects (23 dentate males, 9 edentulous males, and 15 dentate females) aged 20-45 years, 37 dentate reference individuals (20 males and 17 females) aged 30-39 years, and 14 edentulous reference males aged 55-72 years. The co-ordinates of the palatal landmarks were used to construct a mathematical equation of palatal shape, independent of dimensions. Palatal length, slope, width, and maximum palatal height in both the sagittal and frontal planes were measured. In males, palatal length, width, and height were significantly influenced by both the syndrome and edentulism (analysis of variance, P < 0.05). The same measurements were significantly reduced in Ds compared with dentate females (t-test, P < 0.05). In the sagittal plane, Ds did not modify palatal shape; in the frontal plane, Ds individuals showed a higher palate. Overall, palatal shape was influenced by both Ds and edentulousness. Therefore, Ds seems to alter the normal palatal size and shape, although verification on larger samples is required. The findings of the present study may encourage more interdisciplinary dentofacial therapy in the dental and orthodontic care of Ds subjects.     

Three-dimensional hard tissue palatal size and shape in human adolescents and adults

Hard tissue palatal dimensions and shape in 29 boys and 32 girls (mean age 14 years) and 30 men and 35 women (mean age 20 years), all with a complete permanent dentition including the second molars, and free from respiratory problems, were analyzed. Palatal landmarks were digitized with a computerized 3D instrument, and their coordinates were used to derive a mathematical model of palatal form. Palatal shape (size-independent) was assessed by a four-order polynomial in the sagittal and frontal plane projections. Palatal dimensions in the frontal and sagittal planes were computed, and compared between ages and sexes by two-way factorial analyses of variance. The effect of age on palatal shape was different in the two sexes: while in females the curves in both the frontal and sagittal planes were practically superimposed, in males the youngest subjects had somewhat 'lower' curves than the oldest subjects. Sex had a significant (p<0.05) effect for all variables. Age was significant only for palatal slope in the sagittal plane (p<0.01), and for raphe inclination in the horizontal plane (p<0.05). For all variables but palatal length in the sagittal plane, a significant (p<0.01) sexxage interaction was found: while in males all linear variables were larger in adults than in adolescents, the reverse was found in females. Overall, while in adolescent females palatal form appeared to have already attained adult characteristics, in males some modifications between adolescence and young adulthood were measured. These modifications should be taken into consideration as a possible factor of relapse after orthodontic treatment.     

Rapid palatal expansion in cats: effect of age on sutural cyclic nucleotides

Previous experiments indicate that bone cells respond to externally applied stimuli with fluctuations of cyclic nucleotide levels. The objective of this experiment was to study the response of bone at the midpalatal suture to the application of tensile forces in young and old animals, through an examination of the osteoblastic staining pattern for cAMP and cGMP. The midpalatal suture was rapidly expanded for 0, 10, and 15 days, respectively, in three young and three old cats. Fresh, frozen, unfixed, undecalcified maxillae were sectioned transversely and stained immunohistochemically for cAMP and cGMP. The staining intensity for both nucleotides was increased in the osteoblasts of the young treated animals, while in the old animals the osteoblasts were only faintly stained for cAMP and cGMP. These results demonstrate that bone cells of old animals are less responsive to tensile forces than the corresponding cells in young animals.     

The effect of sex and age on facial asymmetry in healthy subjects: a cross-sectional study from adolescence to mid-adulthood.

PURPOSE: The study assessed the effects of sex and age on 3-dimensional (3D) soft-tissue facial asymmetry. PATIENTS AND METHODS: The 3D coordinates of selected soft-tissue facial landmarks were digitized on 314 healthy white subjects (40 male and 33 female adolescents, aged 12 to 15 years; 73 female and 89 male young adults, aged 18 to 30 years; and 41 male and 38 female adults, aged 31 to 56 years) by an electromagnetic instrument. Facial asymmetry was quantified by detecting a plane of symmetry and the centers of gravity of the right and left hemifaces and by calculating the distance between the 2 centers of gravity (distance from the symmetry [DFS]). Both absolute (millimeters) and percentage (of the nasion-center of gravity distance) DFS were obtained, as well as the maximum normal asymmetry. The asymmetry of single landmarks was also quantified. RESULTS: No gender- or age-related differences were found for both absolute and percentage DFS (P > .05). The maximum normal asymmetry was slightly greater in females than in males of corresponding age; within each sex, the largest values were found in the adolescent group. Tragion, gonion, and zygion were the most asymmetric landmarks in all groups (about 10% to 12% of the nasion-facial center of gravity distance), whereas the least asymmetric was endocanthion (4% to 6%). CONCLUSIONS: A slight soft-tissue facial asymmetry was found in normal subjects. The maximum normal asymmetry could be useful in identifying borderline asymmetric patients.     

Symmetry of palatal shape during the first year of life in healthy infants

Clinical Oral Investigations - The purpose of this study was to quantify the symmetry of the alveolar process of the maxilla and palate during the first year of life in healthy infants with the...     

A comparative study of palatal height in a Saudi and Egyptian population

SUMMARY The present study constitutes an attempt to compare normal traits for palatal height and width at different stages of dentition development of two ethnic groups of the Middle East. The observations were obtained from 346 randomly selected normal subjects, 188 Saudis and 158 Egyptians. The stone models were divided into three categories in both groups — primary, mixed and permanent dentitions. Palatal index values were calculated at two levels. Vernier calipers were used to measure the palatal width. Palatal depth was measured by profile Gauge by Vitrex. The results of this study demonstrate no significant difference between ethnic groups at levels 1 and 2 in relation to the palatal height, width and index. For both groups, palatal index increased significantly from the primary to mixed and permanent dentition at level 1.
At level 2, palatal index and height showed decreases in measurement in the mixed dentition compared with the primary and the permanent dentitions.
Subjective assessment of the palatal height correlated with palatal index. The casts were then labelled so that the shallow group had the smallest palatal index followed by the normal and the deep group had the largest palatal index. The results contribute to the information available on the development of palatal shape within two Middle Eastern populations. Knowledge of the normal range in shape can act as a baseline for studies of certain oral developmental abnormalities.     

The effect of occlusal rest size and shape on yield strength

STATEMENT OF PROBLEM: Occlusal rests, essential for conventional removable partial dentures, may fracture and cause failure of the prosthesis. It is unknown whether alterations in the size or shape of occlusal rests might improve their performance. PURPOSE: In this in vitro study, 3-dimensional finite element analysis was used to evaluate the effects of occlusal rest size and shape on yield strength. MATERIAL AND METHODS: An occlusal rest and a minor connector as part of a clasp assembly were modeled for 3-dimensional finite element analysis with 3 variations of width (2.0, 3.0, and 4.0 mm), thickness (0.7, 1.0, and 1.5 mm) and length (2.0, 3.0, and 4.0 mm). A concentrated vertical load of 100 N was applied at the most protruded point of the occlusal rest base. Maximal principal stress and yield strength were calculated. In addition, the following parameters were altered: radius of curvature at the inner connection (r), thickness of the minor connector (m), inclination of horizontal axis of occlusal rest (i), and thickness at the most protruded point (t). RESULTS: Yield strength increased with increased width (183% to 242% from 2.0 to 4.0 mm) and thickness (141% to 230% from 0.7 to 1.5 mm). Alterations in length had a lesser effect on yield strength (120% to 178% from 4.0 to 2.0 mm). All other parameters except thickness at the most protruded point (t) affected yield strength. CONCLUSION: The results of this in vitro study suggest basic principles for optimizing the size and shape of occlusal rests. In general, increased width and thickness are desirable, whereas overrounded or sharp line angles and excessive rest inclination should be avoided. These principles may be useful in removable partial denture design.     

Effects of tobacco smoking and age on the keratinization of palatal mucosa: a cytologic study.

Cytologic smears of palatal mucosa were evaluated for degree of keratinization in 217 healthy men ranging in age from 30 to 74 years. Two slides were prepared for each participant, and each slide was read by two different pathologists. Three separate high-power fields were examined on each slide, and the percentage of orange-brown cells, either without nuclei or with pyknotic or fragmented nuclei, was recorded. A mean value was obtained for each participant. Each participant had an extensive medical and dental work-up as part of the Veterans Administration Longitudinal Study of Oral Health in Healthy Veterans. Nonsmokers and smokers were divided into five age groups. Smokers at all ages presented a greater degree of palatal keratinization than nonsmokers, but age differences in keratinization were not statistically significant.     

Morphological analysis of palatal rugae patterns in a population of Maharashtrian ancestry: a cross-sectional study

AimTo analyze the morphological parameters of palatal rugae in a population of Maharashtrian ancestry.Material and methodsThis study was conducted on 1000 subjects of Maharashtrian ancestry with at least 3 generations on the mother’s and father’s side. Their palatal impressions were obtained with alginate and the casts were analyzed for length, shape and direction of palatal rugae.ResultsOur results showed that the most predominant rugae were primary followed by secondary and fragmentary with significant differences between them. The most prevalent rugae shapes found were straight followed by wavy followed by curved with significant differences between them. According to direction, forward rugae were significantly higher than perpendicular rugae and backward rugae.ConclusionThe rugae are considered to have population specific configurations. This baseline data of patterns of palatal rugae in a sample of Maharashtrian ancestry may serve `as an accessory tool’ for population identification in Forensic Dentistry.     

The association between coffee consumption and periodontitis: a cross-sectional study of a northern German population

Clinical Oral Investigations - Positive and negative influences on oral health are attributed to coffee consumption. The aim of the current study is to evaluate the association between coffee...     

The effect of keratinized mucosa on the severity of peri-implant mucositis differs between periodontally healthy subjects and the general population: a cross-sectional study

Clinical Oral Investigations - The study aims to investigate the effect of reduced keratinized mucosa (KM) and other risk indicators on the severity of peri-implant mucositis in (i) the general...     

Comparative study of palatal rugae shape in two samples of Egyptian and Saudi children

This study was performed to investigate differences in the shape of the individual palatal rugae in two population samples of Arabian children from Egypt and Saudi Arabia, and develop discriminant function to identify the populations based on rugae shape. A total of 152 stone casts (80 from Egyptian and 72 from Saudi children), equally distributed between genders aged 6–8 years were examined for rugae shape (straight, wavy, curved, circular, unification and cross-link) and their incidence was recorded. Association between rugae shape and gender as well as rugae shape and population were tested using chi-square and discriminant function analyses using SPSS 13 statistical package. Curved and wavy were the most prevalent rugae shape in both groups, followed by straight rugae. Circular, converged and diverged unifications were few in number, while cross-link rugae were not observed in Saudi children. No significant gender differences were observed. Chi-square analysis for association between rugae shape and population groups showed significant differences in curved, wavy, cross-link, converged and diverged unification. Three rugae shapes; wavy, diverging unification and cross-link contributed to the discriminant function which enabled population identification. It was concluded that palatal rugae shape revealed significant differences between the two Egyptian and Saudi populations and also confirmed previous reports of lack of gender dimorphism. Discriminant function analysis allowed differentiation of the populations and it is inferred that discrete variables such as rugae shape are better suited for that purpose than continuous variables such as rugae length.     

The effect of periodontal disease on medical and dental costs in a middle-aged Japanese population: a longitudinal worksite study

BACKGROUND: Although periodontal disease is one of the most common chronic diseases, it is not clear whether periodontal disease is associated with increased health care costs. The authors examined the effect of periodontal disease on medical and dental costs and use for 3.5 years prospectively. METHODS: The data were derived from health and dental examinations and health insurance claims of 4,285 Japanese civil officers aged 40 to 59 years. The subjects were divided into three categories: no pathological pocket, moderate periodontitis, and severe periodontitis. Age, gender, smoking, body mass index, and hypertension were adjusted in a multivariate analysis after excluding subjects with any history of liver disease, heart disease, or diabetes mellitus. RESULTS: The cumulative cost for subjects with severe periodontitis was approximately 21% higher than for subjects with no pathological pocket, and the hospital admission rates of subjects with severe periodontitis were highest (male: odds ratio [OR]=.34; 95% confidence interval [CI]: 1.00 to 1.80; female: OR=1.29; 95% CI: 0.75 to 2.20). In males, the annual hospital costs of subjects with severe periodontitis were 75% higher than for subjects with no pathological pocket. There was no clear trend identified for outpatient care. The annual dental visit rates and costs for subjects with severe periodontitis were highest in both genders. Periodontal disease might increase the medical care costs for diabetes mellitus, digestive disease, and liver disease. CONCLUSION: Periodontal disease may have played an important role in the cumulative health care cost increases in middle-aged adults over a period of only a few years.