Platysma and the cervical superficial musculoaponeurotic system - Comparative analysis of facial crease and platysmal band development.

OBJECTIVE: The superficial musculoaponeurotic system connects the mimic muscles to the skin, allowing mimic expressions with regional morphological architectural differences. The aim of this study was to perform an architectural analysis of the cervical platysma-skin interaction, determine the morphological implications in platysmal band development and compare the findings to the facial SMAS architectural types. METHOD: Full-thickness blocks of skin, SMAS and platysma from seven hemifaces (three male and two female) and full-thickness blocks of skin, SMAS and mimic muscles of the periorbital, perioral, forehead and midfacial regions from six hemifaces (three male and three female) of donor bodies were collected postmortem. Serial histological sections were cut and stained with Azan. After the morphological analysis, three-dimensional reconstruction of the tissue block was performed with AutoCAD. The morphological and mechanical properties of the different facial SMAS types were compared with those of the cervical SMAS. RESULTS: The architecture of the cervical SMAS (type V) consists of parallel, aligned septum fibrosus profundus and septum fibrosus superficialis tissue connected by vertical, aligned septa fibrotica commisurales tissue delimiting fatty tissue compartments transferring platysmal contractions to the skin. The facial morphological dynamic mimic pattern (SMAS types I, II and III) describes the point-by-point transfer of mimic muscle bundle contractions to the skin, explaining facial crease formation. The cervical morphological dynamic mimic pattern (SMAS type V) can be explained by dual traction force collimation over the septum fibrosus superficialis and profundus in platysmal band development. CONCLUSIONS: The cervical SMAS (type V) description supports the hypothesis that the SMAS and platysma have different morphological origins. The two different facial and cervical morphological dynamic mimic patterns support the phenotypical difference between facial fold and platysmal band development.

Impact of probiotics on pathogen survival in an innovative human plasma biofilm model (hpBIOM).

BACKGROUND: Despite of medical advances, the number of patients suffering on non-healing chronic wounds is still increasing. This fact is attended by physical and emotional distress and an economic load. The majority of chronic wounds are infected of harmful microbials in a protecting extracellular matrix. These biofilms inhibit wound healing. Biofilm-growing bacteria developed unique survival properties, which still challenge the appropriate wound therapy. The present in-vitro biofilm models are not suitable for translational research. By means of a novel in-vivo like human plasma biofilm model (hpBIOM), this study systematically analysed the influence of 3 probiotics on the survival of five clinically relevant pathogenic microorganisms. METHODS: Human plasma was used to produce the innovate biofilm. Pathogenic microorganisms were administered to the plasma. By stimulating the production of a fibrin scaffold, stable coagula-like discs with integrated pathogens were produced. The five clinically relevant pathogens P. aeruginosa, S. aureus, S. epidermidis, E. faecium and C. albicans were challenged to the probiotics L. plantarum, B. lactis and S. cerevisiae. The probiotics were administered on top of the biofilm and the survival was quantified after 4 h and 24 h of incubation. For statistics, two-way ANOVA with post-hoc Tukey's HSD test was applied. P-value > 0.05 was considered to be significant. RESULTS: SEM micrographs depicted the pathogens on the surface of the fibrin scaffold, arranged in close proximity and produced the glycocalyx. The application of probiotics induced different growth-reducing capacities towards the pathogens. B. lactis and S. cerevisiae showed slight bacteria-reducing properties. The survival of C. albicans was not affected at all. The most antimicrobial activity was detected after the treatment with L. plantarum. CONCLUSIONS: This study successfully reproduced a novel human biofilm model, which provides a human wound milieu and individual immune competence. The success of bacteriotherapy is dependent on the strain combination, the number of probiotics and the activity of the immune cells. The eradicating effect of L. plantarum on P. aeruginosa should be emphasized.

Histological, SEM and three-dimensional analysis of the midfacial SMAS - New morphological insights.

INTRODUCTION: The superficial musculoaponeurotic system (SMAS) of the midface has a complex morphological architecture, and a multitude of controversial opinions exist regarding its in vitro appearance and clinical relevance. The aim of this study was to investigate the three-dimensional architecture of the midfacial SMAS. METHOD: Histological and SEM analyses were performed on tissue blocks of the skin, subcutaneous tissue and mimic musculature of the midfacial region between the anterior parotid gland pole and lateral to the nasolabial fold and tissue blocks of the skin, subcutaneous tissue and parotid fascia. Blocks were collected postmortem from six formalin-fixed donor bodies. Serial histological sections were made, stained with Azan and digitized. Three-dimensional reconstructions and visualization of the tissue blocks were performed using AutoCAD. RESULTS: Two different SMAS architectures were found in the midfacial region: parotideal (type IV) and preparotideal (type I) SMAS. Type I SMAS showed three-dimensional interconnecting fibrous chambers embracing fat tissue lobules that cushioned the space between the skin and mimic musculature. Fibrous septa divided the mimic musculature surrounding the muscular bundles. Beneath the mimic muscular level, SMAS septa were oriented parallel to the muscular plane. Above the mimic muscular plane, SMAS septa were oriented perpendicularly, inserted into the skin. Type IV SMAS showed a parallel alignment of the fibrous septa to the skin level, anchoring the skin to the parotid fascia, presenting lymphatic nodes in the fat tissue compartments. The fat cells of the SMAS were enveloped in a fibrotic membrane at the border of the fibro-muscular septa. The SMAS blood supply comprised two subcutaneously epimuscularly spreading anastomosing vascular systems. CONCLUSIONS: Midfacial SMAS represents a functional unit with physical and immunological tasks appearing in two different morphological architecture types. A well-defined nomenclature is needed to prevent controversy.

Bacterial viability in oral biofilm after tooth brushing with amine fluoride or sodium fluoride.

OBJECTIVE: The aim of this study was to investigate the effects of sodium fluoride (NaF) and amine fluoride (AmF) on bacterial viability in the oral cavity. MATERIAL AND METHODS: Healthy subjects brushed their teeth with either fluoride free toothpaste, NaF- or AmF-containing toothpaste. Biofilm smears from different locations were collected before and immediately and 30 and 120 min after tooth brushing. The smears were stained with live/dead bacterial staining, and the number of the respective bacteria was counted. The data were statistically analyzed by comparing the numbers of bacteria before and after the application of no fluoride, NaF and AmF. RESULTS: The highest numbers of bacteria were found in the tongue biofilm, followed by the palatal and cheek biofilm. The lowest numbers were found in the mouth floor biofilm. After the application of AmF, no changes in the numbers of bacteria were found in the biofilms, except for the cheek, where they were reduced. After the application of NaF, the number of bacteria decreased significantly in all biofilms. After 120 min, bacterial regrowth was complete. CONCLUSIONS: AmF has only little effect on the bacterial viability of oral biofilms. NaF application reduces the number of living bacteria in the oral biofilms. This effect lasts not longer than 120 min.

Morphological analysis and three-dimensional reconstruction of the SMAS surrounding the nasolabial fold.

BACKGROUND: The superficial musculoaponeurotic system (SMAS), a structure that has been discussed with some controversy, has a complex morphological architecture. MATERIAL AND METHODS: Histological analysis was performed on tissue blocks of the nasolabial fold (NLF) collected postmortem from formalin-fixed bodies of one male and one female donor. Serial histological sections were made, stained and digitized. Three-dimensional reconstructions of the histological structures were performed. Specimen- and location-specific differences were determined. SEM analysis of the NLF tissue block was performed. RESULTS: The NLF SMAS is a fibro-muscular, three-dimensional meshwork bolstered with fat cells. Two SMAS structure types were identified adjacent to the NLF. The cheek SMAS structure showed a regular, vertical and parallel alignment of the fibrous septa, building a three-dimensional meshwork of intercommunicating compartments. It changed its morphology, condensing while transiting the NLF and passing over to form an irregular structure in the upper lip region. SEM analysis demonstrated the connection between the fibrous meshwork and the fat cells. SMAS blood circulation expanded subcutaneously without perforating the fibro-muscular septa. CONCLUSIONS: The NLF has a recognizable condensed cheek SMAS structure and represents the transition zone between the two SMAS types. Specimen-specific morphological differences necessitate individual planning and area-specific surgical procedures.

Three-dimensional reconstruction of the suborbicularis oculi fat and the infraorbital soft tissue.

The aim of this study was to reveal the histomorphological connections among the suborbicularis oculi fat (SOOF), the orbicularis oculi muscle (OOM), the superficial musculoaponeurotic system (SMAS), the infraorbital fat and the skin. Full graft tissue blocks of the infraorbital region with the skin, SMAS, OOM and SOOF were collected post mortem from one female and two male formalin-fixed body donors. Serial histological sections were made, stained and digitized. Digitalization and three-dimensional (3D) reconstruction of the histological meshwork were performed. SOOF was revealed as a fibro-adipose tissue underlying the OOM, which was strictly separated from the intraorbital fat pad by the orbital septum. SOOF, OOM and SMAS were connected by fibrous septa derived from the SOOF, traversing the OOM with division into multiple muscular bundles, continuing above the muscular plane by forming the SMAS and ending with skin insertion. In the infraorbital region, two different types of SMAS bordering the infraorbital fold have been recognized. Muscle cells have been demonstrated in the SMAS fibrous septa of both SMAS types. Together with the OOM, the SMAS and the skin, SOOF forms an anatomical functional unit. Muscular contraction of the OOM could be transferred by the SMAS to the skin level, producing periorbital mimic expression. The 3D reconstruction facilitates the comprehension of the morphological structure, its connections and space correlations in the infraorbital area. The morphological and topographical peculiarities of the infraorbital structures make it possible to conclude that surgical interventions in this area need to be elaborated and individualized.

Parallel study about the effects of psychotherapy on patients with dental phobia determined by anxiety scores and saliva secretion and composition.

BACKGROUND: The aim of this study was to determine the success of psychotherapeutic treatment for dental phobia by measurement of anxiety using the dental anxiety score (DAS), the state trait anxiety score (STAI state), salivary cortisol and protein concentrations and the salivary secretion rate. Primary endpoint of the study was the comparison of the data before and after psychotherapeutic treatment. METHODS: Forty patients were included into the study. Twenty-four were allocated to the phobic group, 16 to the control group. Saliva was collected upon entering the dental clinic and again after three weeks of psychotherapy. The results were compared with those of a control group. The DAS and STAI questionnaires were completed at each visit. RESULTS: A reduction in DAS values was found after psychotherapy. However, the values remained significantly higher in the phobic group than in the controls. Similar results were found for STAI scores. A slightly higher salivary cortisol level was found in the phobic group. No changes occurred in cortisol or protein concentrations. The salivary secretion rate increased in the phobic patients after psychotherapy. CONCLUSIONS: It could be concluded that psychotherapy is effective in the treatment of dental phobic patients. TRIAL REGISTRATION: This study has been retrospectively registered in the German Clinical Trials Register (# DRKS00009552 ) on 10/19/15.

Dentin abrasivity of various desensitizing toothpastes.

BACKGROUND: The aim of this study was to compare the abrasivity of various commercially available toothpastes that claim to reduce dentin hypersensitivity. METHODS: Dentin discs were prepared from 70 human extracted molars. The discs were etched with lemon juice for 5 min, and one half of the discs were covered with aluminum tape. Following this, they were brushed with 6 different toothpastes, simulating a total brushing time of 6 months. As a negative control, discs were brushed with tap water only. The toothpastes contained pro-arginine and calcium carbonate, strontium acetate, stannous fluoride, zinc carbonate and hydroxyapatite, new silica, or tetrapotassium pyrophosphate and hydroxyapatite. After brushing, the height differences between the control halves and the brushed halves were determined with a profilometer and statistically compared using a Mann-Whitney U test for independent variables. RESULTS: A significant difference (p < 0.001) in height difference between the controls and the toothpaste-treated samples was found in all cases, except for the stannous fluoride-containing toothpaste (p = 0.583). The highest abrasion was found in the toothpaste containing zinc carbonate and hydroxyapatite, and the lowest was found in the toothpaste containing pro-arginine and calcium carbonate. CONCLUSIONS: Desensitizing toothpastes with different desensitizing ingredients have different levels of abrasivity, which may have a negative effect on their desensitizing abilities over a long period of time.

Enamel surface alterations after repeated conditioning with HCl.

BACKGROUND: The aim of this study was to investigate the influence of etching time with 15% hydrochloric acid (HCl) on the enamel surface destruction by studying the resulting roughness and erosion depth. METHODS: The vestibular surfaces of 12 extracted, caries free human incisors were divided into four quadrants, and each quadrant was etched with 15% HCl for different numbers of etching cycles (1×2, 2×2, 3×2 and 4×2 min). Surface roughness and erosion depth were measured quantitatively with optical profilometry, and the surface morphology was imaged with scanning electron microscopy (SEM). RESULTS: After two minutes of 15% HCl application a median enamel substance loss of 34.02 µm was observed. Lengthening of etching time (2×2, 3×2 and 4×2 min) resulted in significantly increase in erosion depth to each additionally, between 13.28 -15.16 µm (p < 0.05) ending up in a total median enamel surface loss of 77 µm. Regarding surface roughness no significant (p > 0.05) difference was found between unetched enamel and the etched enamel surfaces. CONCLUSION: Repeated 15% HCl conditioning of the enamel surface increases the depth of the etched surface erosion. However, the total erosion depth is rather shallow and therefore negligible.

Effectiveness of various toothpastes on dentine tubule occlusion.

OBJECTIVE: Dentine hypersensitivity is an increasing problem in dentistry. Several products are available that claim to occlude open dentine tubules and to reduce dentine hypersensitivity. The aim of this study was to investigate the effectiveness of several different products on dentine tubule occlusion using qualitative and quantitative methods. MATERIALS AND METHODS: Dentine discs were prepared from extracted human premolars and molars. The dentine discs were brushed with 6 different experimental toothpastes, 1 positive control toothpaste and 1 negative control without toothpaste; the brushing simulated a total brushing time of 1 year. Half of the discs were etched with lemon juice after toothpaste application. Standardized scanning electron microphotographs were taken and converted into binary black and white images. The black pixels, which represented the open dentine tubules, were counted and statistically evaluated. Then, half of the dentine discs were broken, and the occlusion of the dentine tubules was investigated using energy dispersive X-ray spectroscopy (EDS). RESULTS: The number of open dentine tubules decreased significantly after brushing with 5 of the 6 tested toothpastes. A significant effect was observed after acid erosion for 3 of the 6 tested toothpastes. EDS revealed partly closed dentine tubules after brushing with 3 toothpastes; however, no partly closed dentine tubules were observed after acid erosion. CONCLUSIONS: Some toothpastes are capable of partial dentine tubule occlusion. This occlusion is unstable and can be removed with acid erosion. CLINICAL SIGNIFICANCE: Desensitizing toothpastes are the most common products that are used against dentine hypersensitivity, and these toothpastes affect dentine tubule occlusion.

Effects of different amine fluoride concentrations on enamel remineralization.

OBJECTIVES: The aim of this study was to investigate the effects of decreasing fluoride concentrations on repeated demineralizing challenges on human enamel. MATERIALS AND METHODS: In 24 teeth, 3mm×3mm windows were prepared on the buccal and lingual sides and treated in a cycling demineralization-remineralization model. Remineralization was achieved with 100, 10 and 0.1 ppm fluoride from anime fluoride. Coronal sections were cut through the artificial lesions, and three sections per tooth were investigated using polarized light microscopy and scanning electron microscopy with quantitative element analysis. RESULTS: The morphology of the lesions was studied, and the extensions of the superficial layer and the body of the lesion were measured. Using element analysis, the Ca, P and F content were determined. The body of the lesion appeared remineralized after application of 100 ppm fluoride, while remineralization of the lesion was less successful after application of 10 and 0.1 ppm fluoride. The thickness of the superficial layer increased with decreasing fluoride concentrations, and also the extension of the body of the lesion increased. Ca and P content increased with increasing fluoride concentrations. CONCLUSIONS: The effectiveness of fluoride in enamel remineralization increased with increasing fluoride concentration. CLINICAL RELEVANCE: A consistently higher level of fluoride in saliva should be a goal in caries prevention.

Kinetics of fluoride bioavailability in supernatant saliva and salivary sediment.

UNLABELLED: The assessment of the fluoride kinetics in whole saliva as well as in the different salivary phases (supernatant saliva and sediment) is essential for the understanding of fluoride bioavailability. OBJECTIVES: To assess the fluoride content, provided by sodium fluoride and amine fluoride, in the supernatant saliva and in salivary sediment. METHODS: Seven trained volunteers were randomly attributed to 2 groups in a cross-over design and brushed their teeth in the morning for 3 min with a product containing either sodium fluoride or amine fluoride. Saliva was collected before, immediately after tooth brushing and 30, 120, and 360 min later and measured. The samples were centrifuged 10 min at 3024 × g. Fluoride content of the supernatant saliva and of the sediment was analysed using a fluoride sensitive electrode. All subjects repeated the study cycles 2 times, and statistical analyses were made using the nonparametric sign test for related samples, the Wilcoxon-Mann-Whitney-test for independent samples. RESULTS: There was a significant increase in fluoride immediately after tooth brushing in both groups in saliva and sediment. The distribution of fluoride between salivary sediment and supernatant saliva (ratio) varied considerably at the different collection times: decreased from 17.87 in baseline samples of saliva to 0.07 immediately and to 0.86 half an hour after tooth brushing in the sodium fluoride group and from 14.33 to 2.85 and to 3.09 in the amine fluoride group. Furthermore after 120 min and after 360 min after tooth brushing the ratio increased from 17.6 to 31.6 in the sodium fluoride group and from 20.5 to 25.76 in the amine fluoride group. No difference was found in the sediment-supernatant saliva ratio between the sodium fluoride and the amine fluoride groups 360 min after tooth brushing. CONCLUSION: For the assessment of fluoride kinetics in whole saliva it is necessary to pay attention to at least four factors: fluoride formulation, time after fluoride application, fluoride concentration in supernatant saliva and fluoride concentration in salivary sediment. This study was approved by the Ethical Committee of the University of Witten/Herdecke permission 21/2008.

Light- and electronmicroscopic study of infiltration of resin into initial caries lesions--a new methodological approach.

It was the purpose of this pilot study to investigate resin infiltration into various types of initial subsurface caries lesions using a combined microscopic technique with polarized light microscopy and fluorescence microscopy and subsequent scanning microscopy with EDX-element analysis. Six extracted premolars with initial caries lesions were used. Five were infiltrated with resin after imbibition of the subsurface carious pore volume of enamel with sodium fluorescein solution. After light curing the unbound dye was removed by washing out in water. Serial sections were cut through the lesions and investigated with polarized light microscopy, fluorescence microscopy and simultaneously with both microscopic techniques. The same sections were then studied with scanning electron microscopy and EDX-element analysis to prove the infiltration of the resin into the lesions. The results showed, that the combination technique adds further morphologic information to infiltration behaviour of the resin. The individual volume of early acute lesions versus chronic lesions involving dentin, and the fluorescein bound by resin was well documented in serial sections. The EDX calcium and phosphorus signals correlate negatively with the lesion extension, and the carbon signal correlates positively, thus labelling the resin infiltration. It could be demonstrated that resin infiltration is dependent from the pore volume of the lesion. It can be concluded that the combined polarized light microscopy with fluorescence microscopy is an advantageous tool for studying infiltration of resin into hard tissues.

The predictive value of criteria for student admission to dentistry.

INTRODUCTION: In this study, we investigated the value of an individual selection procedure to choose dental students for the Faculty of Dental Medicine at the University of Witten/Herdecke, Germany. The selection procedure was divided into the following four steps: step one consisted of a formal application; step two consisted of a practical test; step three consisted of a personal interview; and step four consisted of a final selection by an independent committee. MATERIAL AND METHODS: Data from 196 students were collected from the university files. The following data were compared: the grades of the final secondary school certificate (Abiturnoten) were compared with the grades of the Natural Science Examination (naturwissenschaftliche Vorprüfung), first Dental Examination (zahnärztliche Vorprüfung) and State Board Examination (Staatsexamen); specialisation or non-specialisation at secondary school in natural sciences was compared with the grades of the Natural Science Examination and the first Dental Examination; the results of the practical test of the selection procedure were compared with the grades of the practical examination in the first Dental Examination; the interview recommendations to the committee were compared with the grades of the first Dental Examination and the State Board Examination. RESULTS: The results showed a positive correlation (R = 0.34; P < 0.001) between the secondary school grades and the Natural Science Examination grades. The correlation was weaker between the grades of the first Dental Examination and State Board Examination. No correlation was found between the specialisation during secondary school in biology, chemistry and physics or non-specialisation, and the results of the Natural Science Examination and first Dental Examination. A weak correlation was found between the grades the candidates obtained in the practical test of the selection procedure and the first Dental Examination.

EDX-Element Analysis of the In Vitro Effect of Fluoride Oral Hygiene Tablets on Artificial Caries Lesion Formation and Remineralization in Human Enamel.

Aim of this in-vitro-study was to assess the remineralization potential of a tooth cleaning tablet with different fluoride content quantitatively using EDX analysis.Twenty three caries free impacted third molars were examined; enamel surfaces were wax coated leaving two 3x4mm windows for exposure to demineralization/remineralization cycles. The teeth were randomly assigned to 4 groups of 5 control and 6 experimental teeth each. Demineralization by standardized HEC-gel, pH 4.7 at 37°C for 72h, was alternated by rinsing in remineralization solution, pH 7.0 at 37°C for 72h, total challenge time 432h. The negative control group N was treated during remineralization cycles with saline; positive control group P was treated with remineralization solution; experimental group D1 was exposed to remineralization solution containing Denttabs(®)-tablets with 1450 ppm F; experimental group D2 was exposed to remineralization solution and Denttabs(®)-tablets with 4350 ppm F. Each tooth was cut into serial sections and analyzed by scanning electron microscopy with EDX element analysis for assessment of the different zones of the lesions in 3 representative sections. Statistical analysis was based on the AVOVA test for repeated measurements and post hoc Bonferroni adjustment. The results showed a significantly higher Ca and P content in the body of the lesion in both fluoride treated groups compared to the controls. It can be concluded that higher concentrations of NaF may be more effective in remineralization of early advanced caries lesions.

Influence of individual saliva secretion on fluoride bioavailability.

UNLABELLED: The aim of this preliminary investigation was to compare the individual saliva secretion rate with the fluoride bioavailability in saliva after using sodium fluoride and amine fluoride. METHODS: To assess oral fluoride kinetics 10 highly trained volunteers brushed their teeth with one of the formulations and saliva was collected. The amount of saliva was measured, and the fluoride content was determined. Data underwent statistical analysis using the Mann-Whitney-U test and Pearson correlation. The ex vivo experiment I included individual saliva collection of the same volunteers. Then the oral hygiene products were solved in equal amounts of whole saliva (ex-vivo experiment II), and the fluoride content was measured. Finally, both products were dispersed in distilled water (ex-vivo experiment III) to calculate the dissociation of both products in water. RESULTS: In vivo results of fluoride content after 3 min. tooth brushing demonstrated a negative correlation with saliva secretion: for NaF r = -0.695 (p<0.01) and for amine fluoride r = -0.446 (p<0.01). The in-vitro experiment I resulted for NaF in 251.7±22.4 µg/g fluoride and for amine fluoride in 171.7±14.4 µg/g. CONCLUSIONS: Fluoride bioavailability of saliva after exposure to NaF was higher compared to amine fluoride. The individual secretion rate changes the fluoride content and normal secretors keep the fluoride availability longer.

Quantitative analysis of the calcium and phosphorus content of developing and permanent human teeth.

It was the aim of this study to investigate the distribution of Ca, P and C in predentin, dentin and enamel in human tooth buds and permanent teeth by EDX element analysis. The mandible of a 16-week-old human fetus containing eight mineralizing tooth buds and three human permanent molars were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80 microm thickness of the mandible were cut in the frontal-dorsal direction, and polarized light micrographs were taken of these sections. The permanent teeth were cut in mesio-distal direction. The sections were investigated with scanning electron microscopy and EDX element analysis with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, mature dentin, mineralizing enamel and young enamel of developing teeth and mature enamel of permanent teeth. In developing teeth the Ca and P content increased rapidly from outer predentin towards mineralizing dentin. In enamel prisms of developing teeth the Ca and P content increased linearly from the surface towards the enamel-dentin junction. In permanent teeth only a small layer of predentin was found. The Ca and P content in enamel and circumpulpal dentin of permanent teeth was higher than in developing teeth. The Ca/P ratio differed between predentin and dentin areas reflecting different calcium phosphate compositions, but it was the same in mineralizing and young enamel. The differences in the distribution of Ca and P reflect different mineralizing patterns of the enamel and dentin matrices.

Morphology of the auditory tube and palatal muscles in a case of bilateral cleft palate.

OBJECTIVE: There is an increased incidence of otitis media in children with cleft palate, which may be related to the pathology of the auditory tube and palatal muscles. In the present study, the head of a human on term born fetus with bilateral palatal cleft was serially sectioned and the anatomy of the auditory tube and palatal muscles were studied by computer-aided three-dimensional reconstruction. RESULTS: The results showed a nearly horizontal course of the auditory tube. The tensor veli palatini muscle had a bony attachment on either side. The levator veli palatini muscle also showed an abnormal course. CONCLUSIONS: This abnormal course may result in obstruction of the auditory tube during contraction. These pathological findings may explain the higher frequency of otitis media in children with cleft palate.

3D reconstruction of the cardiovascular and central nervous system of a human embryo Carnegie-stage 15--case report.

A human embryo at Carnegie stage 15 was serially sectioned and 3D computer aided reconstructions were made to demonstrate the cardiovascular system and cranial structures and to study developmental variations at this stage. The development of the heart and pharyngeal arteries was according to the existing literature. Differences were found in the development of the arterial circle of Willis and the central nervous system. The cranial venous system seemed to show great variability. Whereas the telencephalon was not developed according to the stage, the development of the hypophysis had occurred prior to stage 15. From the results we conclude that there are remarkable individual differences in embryological differentiation of structures which have to be taken into account during staging of human embryos.