Distribution of TAS2R38 bitter taste receptor phenotype and haplotypes among COVID-19 patients.

Bitter taste receptor TAS2R38 is expressed in the respiratory tract and can respond to quorum-sensing molecules produced by pathogens, stimulating the release of nitric oxide, with biocidal activity. TAS2R38 presents two main high-frequency haplotypes: the "taster" PAV and the "non-taster" AVI. Individuals carrying the AVI allele could be at greater risk of infections, including SARS-CoV-2. The aim of this study was to assess the frequency of PAV and AVI alleles in COVID-19 patients with severe or non-severe symptoms compared to healthy subjects to further corroborate, or not, the hypothesis that the PAV allele may act as a protecting factor towards SARS-CoV-2 infection while the AVI one may represent a risk factor. After careful selection, 54 individuals were included in the study and underwent genetic analysis and PROP phenotype assessment. Our investigation could not point out at a significant relationship between single nucleotide polymorphisms responsible for PROP bitterness and presence/severity of SARS-CoV-2 infection, as previous studies suggested. Our results uncouple the direct genetic contribution of rs10246939, rs1726866 and rs713598 on COVID-19, calling for caution when proposing a treatment based on TAS2R38 phenotypes.

The efficacy of myofunctional therapy in patients with atypical swallowing.

PURPOSE: The myofunctional treatment (MFT) is a conventional therapy in the treatment of oral disease like atypical swallowing (AS). Functional (standardized surface electromyographic analysis-ssEMG) and clinical ("orofacial muscular evaluation with score" protocol-OMES) analyses were conducted to detect the effects of MFT (10 weeks session) in a group of patients with AS. METHODS: ssEMG was performed to analyze the activity of masseter (MM), temporalis (TA), and submental (SM) muscles before (T1) and after (T2) the MFT in a group of 15 patients. OMES was completed at the same timepoints. A Student-t test was carried out to detect differences between T1 and T2 for ssEMG data, and a signed RANK test was used for OMES ones. One-way ANOVA variance test was performed to detect any differences between the different couples of muscles at each timepoint. RESULTS: After MFT, patients showed a shorter duration of the whole act of swallowing (p < .0001), higher intensity of the SM activity (p < .01) than at T1. At T2 masticatory muscles showed lower values for the activation index (ANOVA, p < .0001) and for the spike position (ANOVA, p < .01) than SM. The OMES protocol showed a significant increase for the total evaluation score (p < .01), appearance-posture (p < .01) and functions (p < .001). CONCLUSIONS: MFT permits a shortening of the muscular activation pattern and an increase in SM activity. The improvement of oral functionalities is possible and identifiable thanks to the use of standardized protocols.

Cephalometric traits in children and adolescents with and without atypical swallowing: A retrospective study.

AIM: It has been suggested that atypical swallowing (AS) may negatively influence the skeletal and alveolar development, but its specific effects are still unclear. The aim of this work is to compare the cephalometric characteristics of children and adolescents with and without AS. MATERIALS AND METHODS: Study design: Case-control retrospective cross-sectional study. One hundred patients with (AS group) and 100 patients without AS (control group, C) were retrospectively selected. Their cephalometric data before orthodontic treatment were compared using a 3-way ANOVA variance test to detect any differences between groups considering: the type of swallowing (AS vs C); whether or not the second dentition was completed (SDC vs SDNC); and the gender (males-M and females-F). In addition, a Student-t test for unpaired data was carried out to detect differences between M and F within the AS and C groups. RESULTS: When compared to the controls, AS patients showed a significantly decreased SNB angle (p<.01), increased ANB and SN^Go. Me angles (p<.0001), increased overjet and lower facial height (p<.01), decreased overbite (p<.0001), and increased proclination of the upper incisors. AS-SDC patients also showed significantly increased alveolar length. Within the AS and C groups, skeletal and alveolar measurements were larger in males, with higher significance in the C group, suggesting a different trend of growth in AS patients. CONCLUSION: AS seems to affect the skeletal growth causing mandibular clockwise rotation, skeletal Class II, open bite and incisor proclination. To compensate for these effects, an increase in alveolar growth together with molar eruption seems to be induced.

Rapid Maxillary Expander and Eruption Guidance Appliance therapy in skeletal Class II: cephalometric considerations.

AIM: The use of rapid maxillary expander (RME) combined with eruption guidance appliances (EGA) represents a valid method in the treatment of skeletal Class II deep bite patients. In this paper a retrospective cephalometric study of the effects of RME and EGA therapy in Class II deep bite patients is described and compared with the treatment effects of patients with the same malocclusion treated only by RME. MATERIALS AND METHODS: Pre and post treatment cephalometric radiographs of 47 Class II division 1 deep bite growing patients treated with RME followed by EGA (mean age 9.65 years) (Group 1) were compared with those obtained from a control group (Group 2) of 44 patients (mean age 9.34 years) treated with RME only. The following cephalometric values were analized: SNA; SNB; ANB; SN-PNS.ANS; SN-Go.GN; N-Me; S-Go. RESULTS: Improvement in maxillo-mandibular relationship was observed in both groups with significantly higher decrease of SNA and ANB in group 1. The cranio-maxillary relation shows a tendency to grow downward and backward in both groups. Both anterior and posterior total facial heights showed a significant increase in group 1. CONCLUSIONS: RME followed by EGA therapy in Class II skeletal deep bite patients has shown better results compared with RME therapy without functional appliance.

Preliminary approach for the surface electromyographical evaluation of the oral phase of swallowing.

Swallowing is a muscular activity that occurs both after mastication and spontaneously as a result of saliva accumulation. Spontaneous saliva swallowing occurs about every 2 minutes. Comprehension of its functional mechanisms is relevant to assess their modification in clinical situations. A standardised surface electromyographical (ssEMG) protocol for the evaluation of this muscle activity is lacking. Aims of the present study are: (i) to determine the reproducibility of a ssEMG protocol for the evaluation of the oral phase of saliva swallowing and (ii) to evaluate the activity of masseter (MM), anterior temporalis (TA), submental muscles (SM) to draw a reference model of swallowing. Standardised surface electromyographical activity of MM, TA and SM during swallowing of saliva spontaneously accumulated was recorded in 20 healthy participants. Functional indexes including symmetry (POC), recruitment (Impact), duration of activation of each couple of muscles and of the whole exercise, position, intensity of the spike were computed. Inter- and intra-appointment reliabilities were assessed and method errors calculated. Descriptive statistics, sex- and muscles-related comparisons were carried out. Standardised surface electromyographical assessment of MM, TA and SM muscles was reliable. A high inter-individual variability was found. Percentage overlapping coefficient (POC) values were close to 80% for TA and SM, higher than for MM (P < .001). Impact values ranged between 16.4% and 30.7%, and differences were found between muscles (P < .001). The global muscle activity during swallowing lasted between 1.5 and 1.8 seconds. For each couple of muscles, the duration of activation ranged between 0.7 and 1.6 seconds and muscles-related differences were found (P < .001). The spike of activation for each couple of muscle ranged between 35.7% and 44.2% of the duration. The protocol was reliable and intra-participants repeatable measures can be carried out. Due to the high inter-participants variability, further analyses are needed to draw a model of muscular activity.

Craniofacial structures' development in prenatal period: An MRI study.

INTRODUCTION: The development of skeletal structures (cranial base, upper and lower) and upper airways spaces (oropharyngeal and nasopharyngeal) of the skull has always been an issue of great interest in orthodontics. Foetal MRI images obtained as screening exam during pregnancy can help to understand the development of these structures using a sample cephalometric analysis. MATERIAL AND METHODS: A total of 28 MRI images in sagittal section of foetuses from 20th to 32th weeks of gestation were obtained to dispel doubts about the presence of skeletal malformations. Cephalometric measurements were performed on MRI T2-dependent images acquired with a 1.5 T scanner. The Software Osirix 5 permits to study sagittal and vertical dimensions of the skull analysing linear measurements, angles and areas of the skeletal structures. RESULTS: Vertical and sagittal dimension of cranial base, maxilla and mandible grow significantly (P < .01) between the second and third trimester of gestational period as well as nasopharyngeal and oropharyngeal spaces (P < .05). High correlation between the development of anterior cranial base and functional areas devoted to speech and swallow is demonstrated (r: .97). CONCLUSIONS: The development of craniofacial structures during foetal period seems to show a close correlation between skeletal features and functional spaces with a peak between the second and third trimester of gestation. MRI images result helpful for the clinician to detect with a sample cephalometric analysis anomalies of skeletal and functional structures during prenatal period.

Local wound healing biomarkers for real-time assessment of periodontal regeneration: pilot study.

BACKGROUND AND OBJECTIVES: Within the same surgical procedure, a great variability on achievement of clinical outcomes exists and may be associated to different molecular factors related to tissue healing. The aim of the present study was to assess the distribution of clinical success separately in regenerative therapy (REG) and open flap debridement (OFD) to evaluate if factors related with healing of epithelium, connective tissue and bone may be associated to the clinical outcome within each surgical procedure. MATERIAL AND METHODS: Sixteen patients underwent periodontal REG and nine patients underwent OFD. Periodontal wound fluid was collected at baseline, 3-5, 7, 14 and 21 d after surgery, and expression of wound healing proteins was assessed. Pocket depth and clinical attachment level were taken at baseline and at 6 mo of follow-up. Percentage pocket depth reduction and percentage clinical attachment level gain were computed. Patients were regarded as better or worse responders depending on their percentage pocket depth reduction or percentage clinical attachment level gain. RESULTS: Higher percentage of better responders was observed in the REG group (68.7%) compared to the OFD group (22.2%). At 21 d, no difference in the profile of most of the proteins emerged, with two exceptions, both regarding REG treatment. Bone morphogenetic protein-7 tended to increase in better responders and to decrease in worse responders. Matrix metalloproteinase-1 increased in worse responders and remained substantially unchanged in better responders. CONCLUSION: Local expression of matrix metalloproteinase-1 and bone morphogenetic protein-7 during wound healing is associated with the clinical performance of periodontal regenerative surgery. The use of local biomarkers offers the potential for real-time assessment of the periodontal healing process.

Iliac crest fresh-frozen allografts and autografts in maxillary and mandibular reconstruction: a histologic and histomorphometric evaluation.

AIM: The aim of this paper was to compare histologically and histomorphometrically the osseointegration of iliac crest fresh-frozen allografts and autografts in human pre-prosthetic maxillary and mandibular onlay bone blocks reconstruction. METHODS: Twelve patients with edentulous atrophic ridges, scheduled for implant-supported prosthetic restorations, underwent reconstruction using iliac crest fresh-frozen allografts (group A, six patients) or autografts (group B, six patients). Four-to-nine months later implants were placed in the augmented areas and bone specimens were simultaneously obtained using trephine burs. The specimens were processed for ground sections and evaluated histologically and histomorphometrically. RESULTS: The postoperative course was uneventful in all patients in group B and in all except one in group A. Late complications occurred in 5 patients of group A. Dental implants could be inserted in all cases. Specimens from group A showed a vascularized bone with osteoprogenitor stem cells and medium-high grade of bone remodeling. Small areas of necrotic bone were observed sporadically. Sections obtained from group B revealed an advanced stage of bone remodeling. The histomorphometric analysis showed in group A a mean proportion of 24.7±14.7% for lamellar bone, 28.4±13.3% for newly formed bone and 46.9±16.9% for bone marrow; in group B the corresponding values were 25.3±15.3%, 22.9±11.0%, 51.7±15.7%. No statistically significant difference was found (Wilcoxon Test; P>0.05). CONCLUSION: There were no significant histological differences between group A and B. Larger studies with long term follow-up are needed to confirm that fresh-frozen allografts are a reliable alternative to autografts.

Electromyographic assessment of jaw muscles in patients with All-on-Four fixed implant-supported prostheses.

This study evaluated the electromyographic (EMG) characteristics of masticatory muscles in patients with fixed implant-supported prostheses according to All-on-Four(®) principles and in control healthy dentate subjects. Twenty-six subjects aged 50-74 years were examined. Eighteen were edentulous and had been successfully rehabilitated with (i) mandibular All-on-Four(®) implant-supported fixed prostheses and maxillary complete dentures (10 patients) and (ii) mandibular and maxillary All-on-Four(®) implant-supported fixed prostheses (eight patients). Eight reference subjects had natural dentition. Surface EMG recordings of the masseter and temporalis muscles were performed during maximum voluntary teeth clenching and during unilateral gum chewing. All values were standardised as percentage of a maximum clenching on cotton rolls. During clenching, a good global neuromuscular equilibrium was found in all participants. During chewing, all groups had similar values of working-side muscle activities and of chewing frequency. No significant differences in the analysed EMG parameters were found between the patients with mandibular and maxillary All-on-Four(®) implant-supported prostheses and the reference subjects. In contrast, standardised pooled muscle activities and standardised muscular activities per cycle were larger in patients with a maxillary removable prosthesis than in control subjects (Kruskal-Wallis test, P < 0·01). Also, patients wearing a complete maxillary denture showed a poor neuromuscular coordination with altered muscular pattern and lower values of the index of masticatory symmetry than dentate control subjects (P < 0·01). EMG outcomes suggest that All-on-Four(®) implant-supported prostheses may be considered a functionally efficient treatment option for the rehabilitation of edentulous patients with reduced residual bone volume.

Oral features in five adult patients with Wolf-Hirschhorn syndrome.

The Wolf-Hirschhorn syndrome (WHS) is a rare genetic condition presenting with severe mental disability, growth retardation, muscular hypotonia, seizures, craniofacial abnormalities and defects in the cardiovascular, genitourinary and digestive apparata. To date, few data about oral status of afflicted patients were reported, and this syndrome is still unfamiliar among dental and maxillofacial professionals. Aim of the present case series was to provide oral data from five patients with WHS (3 women and 2 men) aged 19-41 years. All patients entered in a long-stay Institution with an inner dental service in 1998 and underwent regular dental examination and hygiene treatment. Neither tooth agenesis or dental size and shape anomalies were found in the analyzed subjects except for one man showing multiple cone-shaped teeth. At the beginning, bad dental and periodontal conditions with gingival signs and recurrent mucosal inflammation were found in all patients. After motivation of their tutors, dental and periodontal parameters were recorded during periodic assessments and a large decrease in the gingival index was found over time. These data could aware dentists about the therapeutic modalities to improve oral health of WHS patients.

Role of autologous rabbit adipose-derived stem cells in the early phases of the repairing process of critical bone defects.

Adipose-derived stem cells (ASCs) may represent a novel and efficient tool to promote bone regeneration. In this study, rabbit ASCs were expanded in culture and used for the regeneration of full-thickness bone defects in the proximal epiphysis of tibia of 12 New Zealand rabbits. Defects were implanted with graft material as follows: untreated (control), empty hydroxyapatite (HA) disk, ASCs alone, and HA disk seeded with ASCs. Each isolated ASCs population was tested in vitro: they all showed a high proliferation rate, a marked clonogenic ability, and osteogenic differentiation potential. Eight weeks after implantation, macroscopic analyses of all the samples showed satisfactory filling of the lesions without any significant differences in term of stiffness between groups treated with or without cells (p > 0.05). In both the scaffold-treated groups, a good osteointegration was radiographically observed. Even if HA was not completely reabsorbed, ASCs-loaded HA displayed a higher scaffold resorption than the unloaded ones. Histological analyses showed that the osteogenic abilities of the scaffold-treated defects was greater than those of scaffold-free samples, and in particular new formed bone was more mature and more similar to native bone in presence of ASCs. These results demonstrated that autologous ASCs-HA constructs is a potential treatment for the regeneration of bone defects.

Special care dentistry for people with intellectual disability in dental education: an Italian experience.

AIM: This study documented: (i) the curriculum in special care dentistry in the Italian dental schools, as perceived by Deans and by students, (ii) the rate of satisfaction of dental students with their curricular education in special care dentistry, (iii) the attitude of the dental students towards special care dentistry and towards the 'Special Smiles' programme. METHODS: The quality and amount of didactic and clinical training delivered by each dental school for subjects with intellectual disability (ID), the interest of students towards this health field and the 'Special Smiles' programme were collected. Self-administered surveys were sent to the Dean and to all the final year students of all dental schools in 20 Italian Universities. RESULTS: Only four Deans of the 20 dental schools answered the survey, stating to provide didactic and clinical education in special care dentistry. A 51% of student response rate was obtained. Dental students reported to spend about 4% of didactic and 5% of clinical training in the dental care for ID subjects. Most students (83%) rated the training they had received on the topic to be poor. Over 50% of students expressed interest in working in dental offices specifically dedicated to ID patients and 25% of students wished to become Special Smiles volunteers. CONCLUSIONS: Although the paucity of didactic and clinical training in dental care for ID patients, this survey demonstrated a high level of student's interest in learning more about treating these subjects. The current results could suggest to revise the curricular standards of dental schools, by promoting ID-oriented education programmes.

Nasal base symmetry: a three dimensional anthropometric study.

AIM: The aim of this paper was to evaluate directional and fluctuating asymmetry, nostril and alar divergence in the nasal base of healthy young adults. To estimate nostril area and to investigate its relationships with cutaneous nasal area. METHODS: Three-dimensional plaster models of the nose of 20 young healthy white adults were obtained, digitized and mathematically reconstructed using Non Uniform Rational B-Splines (NURBS) curves. Linear distances (alar length, nostril axis length), angles (interalar angle, interaxial angle; angle between each nostril and alar axes), and surface areas (cutaneous nasal surface; right and left nostril area) were computed using NURBS-reconstructed models. RESULTS: The left side nasal structures were somewhat larger than the homologous right side ones (P<0.05). Nostril axis was approximately 60% of the corresponding alar length. Nostril area was approximately 3% of cutaneous nasal area. Alar length explained 31-36% of the individual variations in nostril axis length. Cutaneous nasal area explained 54-56% of nostril area, while the interalar angle explained 35% of the variations in interaxial angle. CONCLUSIONS: The method provided simple measurements of nasal base dimensions and asymmetry; some asymmetry was found also in healthy adults; only moderate relationships between nostril and alar dimensions and angles, as well as between nasal and nostril areas, were found, thus pointing to the necessity of detailed nostril assessments.

Relationship between facial morphology and cervical vertebral shape: a radiographic investigation.

AIM: The aim of this study was to investigate the relationships between the characteristics of cervical vertebrae and craniofacial morphology using a global mathematical method. METHODS: Several cephalometric measurements and the outlines of the second (C2) and fourth (C4) cervical vertebrae were obtained from 45 head films (32 females aged 20-40 years; 13 males aged 21-37 years). Vertebral outlines were mathematically obtained by Fourier series, and the morphological distance between each outline and a reference one was computed. Linear correlations were run between cephalometric variables and morphological distances. RESULTS: Significant correlations (P<0.05) were found between anterior cranial base length (sella-nasion) and the morphological distance of C4 (subjects with a longer cranial base differ more from the reference vertebral outline), and between maxillary length and the morphological distance of C2 (subjects with a shorter maxilla differ more from the reference vertebral outline). The relationship between mandibular base length (Go-Me) and the morphological distance of C2 (subjects with a shorter mandible differ more from the reference vertebral outline) was nearly significant. Within each subject, the two analyzed vertebrae had independent relationships with the reference outlines. CONCLUSION: A significant but limited relationship between craniofacial structures and vertebral morphology was found: at the best, 10% of the differences between the individual vertebral morphology and the reference one may be explained by craniofacial cephalometric measurements. The differences found between C2 and C4 morphologies may show a different effect of suboccipital muscles and of neck muscles within the theories of the functional matrix hypothesis.

Two-dimensional vs three-dimensional assessment of soft tissue facial profile: a non invasive study in 6-year-old healthy children.

AIM: In medical practice, the analysis of facial soft tissues often complement (or even supplement) the evaluation of the hard-tissue relationships. Current technology provides reference data in three dimensions, but clinical practice still uses two-dimensional photographs. In the current study, two-dimensional photographic and computerized, three-dimensional angles measured on the facial profile of children were compared. METHODS: Two-dimensional angular measurements (facial convexity including/excluding the nose; maxillary prominence; nasal prominence; nasolabial; mentolabial; maxillo-labio-mandibular; interlabial) were obtained on the facial profile photographs of 55 boys and 31 girls aged 6; measurements were compared to three-dimensional computerized data collected on 27 boys and 28 girls of the same age and ethnic group. RESULTS: On average, in boys, only the angles of facial convexity including the nose, interlabial, nasolabial and maxillo-labio-mandibular showed differences between the means larger than 2 degrees (up to 2.5 degrees). Statistically significant differences (P<0.05, Watson-Williams' test) were found for the angle of facial convexity including the nose and the maxillary prominence angle. In girls, differences between the two methods larger than 2 degrees were found for the interlabial, maxillo-labio-mandibular (statistically significant), and mentolabial angles (differences up to 7 degrees, corresponding to 4% of the relevant mean). CONCLUSION: The two-dimensional photographic and the three-dimensional computerized data compared in the current study, even not superimposable, seemed sufficiently interchangeable, at least from a clinical point of view. A particular attention should be given to the recording of lip position.

Facial changes in adult uremic patients on chronic dialysis: possible role of hyperparathyroidism.

BACKGROUND: Uremic patients on regular dialytic treatment (RDT) are often affected by a complex metabolic syndrome leading to osteodystrophy. Bone changes are primarily due to high bone turnover, often combined with a mineralization defect leading to increased bone fractures and bone deformities. Although rarely considered, the craniofacial skeleton represents one of the peculiar targets of this complex metabolic disease whose more dramatic pattern is a form of leontiasis ossea. This complication, although described, has never been evaluated in depth nor quantitatively assessed. In order to assess facial deformities in uremic conditions and to understand the possible relation with hyperparathyroidism, we undertook a quantitative evaluation of soft facial structures in a cohort of uremic patients undergoing RDT. METHODS: The three-dimensional coordinates of 50 soft-tissue facial landmarks were obtained by an electromagnetic digitizer in 10 male and 10 female patients with chronic renal insufficiency aged 53-81 years, and in 34 healthy individuals of the same age, ethnicity and sex. Uremic patients were enrolled according to hyperparathyroid status (PTH < 300 pg/mL and PTH > 500 pg/mL). From the landmarks, facial distances, angles and volumes were calculated according to a geometrical face model. RESULTS: Overall, the uremic patients had significantly larger facial volumes than the reference subjects. The effect was particularly evident in the facial middle third (maxilla), leading to an inversion of the mandibular-maxillary ratio. Facial dimensions were increased in all three spatial directions: width (skull base, mandible, nose), length (nose, mandible), and depth (mid face, mandible). The larger maxilla was accompanied by a tendency to more prominent lips (reduced interlabial angle). Some of the facial modifications (nose, lips, mandible) were significantly related to the clinical characteristics of the patients (age, duration of renal insufficiency and PTH levels). CONCLUSIONS: This report, the first in the literature, shows that facial structures of uremic patients are enlarged in comparison with matched normal subjects and that increased bone turnover could be responsible--at least in part--for facial bone changes.

Morphometry of the ear in Down's syndrome subjects. A three-dimensional computerized assessment.

The three-dimensional coordinates of 13 soft-tissue landmarks on the ears were obtained by a computerized digitizer in 28 subjects with Down's syndrome aged 12-45 years, and in 449 sex, age and ethnic group matched controls. From the landmarks, left and right linear distances (ear width and length), ratios (ear width-to-ear length), areas (ear area), angles (angle of the auricle versus the facial midplane) and the three-dimensional symmetry index were calculated. For both males and females, all linear dimensions and areas were significantly (Analysis of Variance, P < 0.001) larger in the reference subjects than in the subjects with Down's syndrome. All values significantly increased as a function of age (P < 0.05); the increment was larger in the reference subjects than in the subjects with Down's syndrome. On both sides of the face, the subjects with Down's syndrome had larger ear width-to-ear length ratios, and larger angles of the auricle versus the facial midplane than the reference subjects. The three-dimensional symmetry index was significantly larger in the reference subjects and in the older persons. In conclusion, ear dimensions, position and shape significantly differed in subjects with Down's syndrome when compared to sex, age and ethnic group matched controls. Some of the differences were sex and age related.

Extracellular glycosaminoglycan changes in healthy and overgrown gingiva fibroblasts after cyclosporin A and cytokine treatments.

BACKGROUND: It has been demonstrated that cyclosporin A (CyA) blocks the immune system, acts on cytoskeleton and stimulates the production of extracellular matrix (ECM) and transforming growth factor-beta1 (TGF-beta1). This cytokine, such as transforming growth factor-alpha (TGF-alpha), induces deposition of glycosaminoglycans (GAG), proteoglycans and collagen fibres in the ECM. METHODS: In this work, we examined the effect induced by CyA, TGF-beta1 and TGF-alpha on cultures of healthy and overgrown human gingival fibroblasts in order to evaluate the glycosaminoglycan, cytoskeletal changes and the behaviour of fibroblasts after concanavalin A (Con A) treatment. Moreover, we examined gingival biopsies by Alcian blue histochemical staining and electron transmission microscopy. RESULTS: Total and extracellular sulphated GAG in overgrown gingiva specimens and in derived fibroblast cultures treated with CyA and cytokines were significantly higher than controls. The action of cytokines was increased (P < or = 0.01) compared with CyA with a greater effect of TGF-alpha in comparison with TGF-beta1; the electron microscopy showed ECM accumulation. The agglutinations showed the heterogeneity of fibroblast populations. CONCLUSIONS: Stimulation with Con A showed that the fibroblast population had cell surface heterogeneity, and could respond in a different way to both CyA and cytokine stimulus. Moreover, increased synthesis of GAG in overgrown gingiva compared with synthesis in normal fibroblasts before CyA treatment suggests a possible genetic origin of damage. As not all CyA-treated patients develop gingival overgrowth, a genetic predisposition may explain the different responses of gingival fibroblast populations.

Single tooth bite forces in healthy young adults.

The assessment of bite forces on healthy single tooth appears essential for a correct quantification of the actual impact of single implant oral rehabilitations. In the present study, a new single tooth strain-gauge bite transducer was used in 52 healthy young adults (36 men, 16 women) with a complete permanent dentition. The influences of tooth position along the dental arch, of side, and of sex, on maximum bite force were assessed by an ANOVA. No significant left-right differences were found. On average, in both sexes the lowest bite force was recorded on the incisors (40-48% of maximum single tooth bite force), the largest force was recorded on the first molar. Bite forces were larger in men than in women (P < 0.002), and increased monotonically along the arch until the first or second permanent molar (P < 0.0001). The present data can be used as reference values for the comparison of dental forces in patients.

Polyamine levels and ornithine decarboxylase activity in blood and erythrocytes in human diseases.

Serum and erythrocyte levels of the polyamines spermine, spermidine and putrescine, as well as ornithine decarboxylase in erythrocytes, were studied in patients with different neoplasms (breast, lung and colon cancer) and in those with a nonmalignant proliferative disease (familial polyposis). The blood levels of polyamines and the spermine/putrescine ratio were significantly higher in all tumors and in nonmalignant colon polyposis. In erythrocyte ornithine decarboxylase activity, spermine and spermidine levels, as well as spermidine/putrescine and spermine/putrescine ratios showed a significant decrease after surgery and chemotherapy. Our data suggest that high levels of blood polyamines and erythrocyte ornithine decarboxylase activity are related to cell proliferation and cancer treatment, but that levels of polyamines in serum and erythrocytes are still significantly high after cancer treatment and are similar to those in polyposis disease. Polyamines are related to nuclear activity during differentiation; therefore, the altered turnover of polyamines could be a sign of abnormal nuclear function. Since polyamines stimulate protooncogene expression, their high levels could be considered an important cofactor in malignant cell transformation.