The lingual nerve: overview and new insights into anatomical variability based on fine dissection using human cadavers

Odontology - This article, for both researchers and clinicians, presents an overview of the lingual nerve and highlights how new insights into human anatomical variability can be gained by...     

Novel Risk Factors for Progression of Diabetic and Nondiabetic CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

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An Obesity Risk Assessment Tool for Young Children: Validity With BMI and Nutrient Values

Objective

Demonstrate validity and reliability for an obesity risk assessment tool for young children targeting families' modifiable home environments.

The pharmacokinetics and cardiovascular effects of high-dose articaine with 1:100,000 and 1:200,000 epinephrine

OBJECTIVES: The authors conducted a randomized, double-blind, two-way crossover clinical trial to compare the pharmacokinetics and cardiovascular effects of 11.9 milliliters of 4 percent articaine hydrochloride (HCl) plus 1:100,000 epinephrine (A100) with those of 11.9 mL of 4 percent articaine HCl plus 1:200,000 epinephrine (A200). METHODS: During two testing sessions, the authors administered injections of A100 and A200 over a seven-minute period (in one-cartridge doses unless otherwise noted): maxillary right first molar infiltration, maxillary left first molar infiltration, maxillary right first premolar infiltration, maxillary left first premolar infiltration, right inferior alveolar injection, left inferior alveolar injection, right long buccal infiltration (one-half cartridge) and left long buccal infiltration (one-half cartridge). They analyzed venous blood samples for articaine levels. They used noninvasive acoustic tonometry to measure a variety of cardiovascular parameters over a two-hour period. RESULTS: Plasma concentration curves of articaine over time were similar for both solutions, with peak concentrations and times to maximum concentration being 2,037 nanograms per milliliter and 22 minutes for A100 and 2,145 ng/mL and 22 minutes for A200. At the 10-minute point, the mean systolic blood pressure and heart rate were significantly elevated (P < .05) with A100 versus A200. CONCLUSIONS: Maximum dose recommendations for the A100 solution also can be applied to the A200 solution. A200 produces less cardiovascular stimulation than does A100. CLINICAL IMPLICATIONS: A200 is as safe as A100, and may be preferable to A100 in patients with cardiovascular disease and in those taking drugs that reportedly enhance the systemic effects of epinephrine.     

The hyoid bone in malay infants with cleft lip and palate.

OBJECTIVE: To compare morphological and positional variations of the hyoid bone in unoperated infants with cleft lip and palate (CL/P) with those in noncleft infants. DESIGN: Retrospective, cross sectional. PATIENTS AND METHODS: Three-dimensional computed tomography scans were obtained from 29 unoperated CL/P infants of Malay origin aged between 0 and 12 months and from 12 noncleft infants in the same age range. Observations were made and measurements were obtained with a software package developed at the Australian Craniofacial Unit. The sizes of the hyoid bones and the position of the hyoid body and epiglottis in relation to the cervical spine were measured. Anatomical anomalies of the hyoid and prevalence of aspiration pneumonia were also documented. RESULTS: The hyoid bones and epiglottis were found to be located more inferiorly in CL/P infants compared with the noncleft infants. Also, 17% (5/29) of the CL/P infants had nonossified hyoid bodies. CONCLUSION: The results suggest that there are differences in the location and genesis of the hyoid bone in infants with CL/P that warrant further investigation.     

Comparison of exposed dentinal surfaces resulting from abrasion and erosion

The aim of this study was to compare the shape of exposed dentinal surfaces caused by abrasion and erosion with a view to developing a diagnostic clinical test. The study material consisted of 80 natural teeth and 129 dental models obtained from Australian Aborigines known to display considerable dental abrasion due to their diet, and dental models of 37 Caucasians diagnosed with dental erosion through detailed history and dietary analysis. Polyvinyl siloxane impressions were obtained of all occlusal surfaces with dentinal scooping in both the ‘abrasion’ and ‘erosion’ groups. All impressions were sectioned buccolingually through the deepest point of the scooped dentine, and then the profiles were photocopied at X 2 magnification. The breadth and depth of dentinal profiles were measured to an accuracy of 0.1 mm, enabling ratios of depth:breadth to be determined, and the position of the deepest part of each scooped surface was recorded. The mean depth:breadth ratio of scooped dentine was significantly greater in the Aboriginal natural teeth (0. 19±60.06, mean±SE) than in the Aboriginal dental models (0.15±0.04). Both Aboriginal natural teeth and models with abrasion showed significantly smaller ratios (p<0.05) than the Caucasian models showing erosion (0.33±.07). Furthermore, in the abrasion samples, the deepest region of the scooped dentine tended to be lingually placed more often in maxillary teeth but buccally placed more often in mandibular teeth (p<0.05). These results indicate that scooped dentine on abraded occlusal surfaces of teeth displays significant differences in shape compared with that caused mainly by erosion.     

Twins and twinning, dentists and dentistry

Comparisons of physical features within identical (monozygous) and non-identical (dizygous) twin pairs have provided valuable insights into the relative contributions of genetic and environmental influences to observed variability. The special nature of the twinning process itself also provides an opportunity to learn more about early human development, including how body symmetry is determined. The mechanisms of twinning, mortality and morbidity in twins, determination of body symmetry including the phenomenon of mirror-imaging, postnatal growth and development of twins, and zygosity determination are discussed. Twin studies with direct relevance to clinical dentistry are reviewed and illustrated by examples from an ongoing investigation of dentofacial morphology in South Australian twins.     

Molar intercuspal dimensions: genetic input to phenotypic variation

Molecular studies indicate that epigenetic events are important in determining how the internal enamel epithelium folds during odontogenesis. Since this process of folding leads to the subsequent arrangement of cusps on molar teeth, we hypothesized that intercuspal distances of human molar teeth would display greater phenotypic variation but lower heritabilities than overall crown diameters. Intercuspal distances and maximum crown diameters were recorded from digitized images of dental casts in 100 monozygotic and 74 dizygotic twin pairs. Intercuspal distances displayed less sexual dimorphism in mean values but greater relative variability and fluctuating asymmetry than overall crown measures. Correlations between intercuspal distances and overall crown measures were low. Models incorporating only environmental effects accounted for observed variation in several intercuspal measures. For those intercuspal variables displaying significant additive genetic variance, estimates of heritability ranged from 43 to 79%, whereas those for overall crown size were higher generally, ranging from 60 to 82%. Our finding of high phenotypic variation in intercuspal distances with only moderate genetic contribution is consistent with substantial epigenetic influence on the progressive folding of the internal enamel epithelium, following formation of the primary and secondary enamel knots.