Accuracy evaluation of a new three-dimensional reproduction method of edentulous dental casts, and wax occlusion rims with jaw relation

The article introduces a new method for three-dimensional reproduction of edentulous dental casts,and wax occlusion rims with jaw relation by using a commercial high-speed line laser scanner and reverse engineering software and evaluates the method’s accuracy in vitro.The method comprises three main steps：（i）acquisition of the three-dimensional stereolithography data of maxillary and mandibular edentulous dental casts and wax occlusion rims;（ii）acquisition of the three-dimensional stereolithography data of jaw relations;and（iii）registration of these data with the reverse engineering software and completing reconstruction.To evaluate the accuracy of this method,dental casts and wax occlusion rims of 10 edentulous patients were used.The lengths of eight lines between common anatomic landmarks were measured directly on the casts and occlusion rims by using a vernier caliper and on the three-dimensional computerized images by using the software measurement tool.The direct data were considered as the true values.The paired-samples t-test was used for statistical analysis.The mean differences between the direct and the computerized measurements were mostly less than 0.04 mm and were not significant（P.0.05）.Statistical significance among 10 patients was assessed using one-way analysis of variance（P,0.05）.The result showed that the 10 patients were considered statistically no significant.Therefore,accurate three-dimensional reproduction of the edentulous dental casts,wax occlusion rims,and jaw relations was achieved.The proposed method enables the visualization of occlusion from different views and would help to meet the demand for the computer-aided design of removable complete dentures.     

A simple,sensitive and non-destructive technique for characterizing bovine dental enamel erosion:attenuated total reflection Fourier transform infrared spectroscopy

Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers’ microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (Po0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATRFTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion.     

Compensation trends of the angulation of first molars:retrospective study of 1 403 malocclusion cases

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1 403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First,angulation of the upper first molar varied significantly with age and tipped most distally in cases aged,12 years and least distally in cases aged.16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability.     

Dental caries and first permanent molar pit and fissure morphology in 7- to 8-year-old children in Wuhan, China

To obtain the caries experience and,plaque accumulation severity and pit and fissure morphology in first permanent molars in 7-8 children in Wuhan,as a reasonable prediction of caries risk and preventive attention in the future,a convenient sample of five primary schools in the vicinity of the Wuhan University School and Hospital of Stomatology was drawn.Two calibrated examiners orally examined all present grade 2 children in the classroom,using standard caries plaque and tooth morphology criteria.Dental caries was scored at enamel(D 2) and dentine(D 3) for tooth and surface level.Independent variables were age,gender and school.Data analysis used analysis of variance and t-test.The sample comprised 1 043 7-and 8-year-olds.The prevalence of dental caries in permanent dentition was 8.7% and in primary dentition,68.7%.Mean Decayed,Missing,Filled Teeth/S(DMFT/S) scores were 0.11 and 0.14,respectively.Mean dmft/s scores were 2.8 and 5.0.The d-component constituted 75% of the d 3 mft index,while enamel carious lesions constituted 36% of the total number of carious lesions(d 2,3-component).Prevalence of medium and deep pits and fissures was 84.6%.Prevalence of medium and severe plaque accumulation was 67.4%.Prevalence of dental caries in the deciduous and permanent dentitions of 7-to 8-year-old children was high.Deep pits and fissures in high caries risk children should be sealed.     

The occlusal plane in the facial context: inter-operator repeatability of a new three-dimensional method

The repeatability of a non-invasive digital protocol proposed to evaluate the three-dimensional(3D) position of the occlusal plane in the face is assessed.Dental virtual models and soft tissue facial morphology of 20 adult subjects were digitally integrated using a 3D stereophotogrammetric imaging system.The digital 3D coordinates of facial and dental landmarks were obtained by two different operators.Camper’s(facial) and occlusal(dental) planes were individuated,and their 3D relationships were measured.The repeatability of the protocol was investigated and showed no significant differences in repeated digitizations.The angle between occlusal and Camper’s planes was smaller than 26 in the frontal and horizontal projections.In the sagittal projection,the angle was observed to be,on average,4.9 6.The determined occlusal plane pitch,roll and yaw values show good agreement with previously published data obtained by different protocols.The current non-invasive method was repeatable,without inter-operator differences and can facilitate assessment of healthy subjects.     

Impacted Lower Third Molar Fused with a Supernumerary Tooth -Diagnosis and Treatment Planning Using Cone-Beam Computed Tomography

This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan＇s radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone-Beam Computed Tomography--which provides precise three- dimensional information--was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone-beam computed tomo- graphy.     

The effect of cold-light-activated bleaching treatment on enamel surfaces in vitro

This in vitro study aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal (Group LP), disto-buccal (Group P), mesio-lingual (Group NP) and disto-lingual (Group L) specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L* but decrease in a* and b*, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.     

Three-dimensional virtual operations can facilitate complicated surgical planning for the treatment of patients with jaw deformities associated with facial asymmetry:a case report

This article describes a case we experienced in which good postsurgical facial profiles were obtained for a patient with jaw deformities associated with facial asymmetry,by implementing surgical planning with SimPlant OMS.Using this method,we conducted LF1 osteotomy,intraoral vertical ramus osteotomy(IVRO),sagittal split ramus osteotomy(SSRO),mandibular constriction and mandibular border genioplasty.Not only did we obtain a class I occlusal relationship,but the complicated surgery also improved the asymmetry of the frontal view,as well as of the profile view,of the patient.The virtual operation using three-dimensional computed tomography(3D-CT)could be especially useful for the treatment of patients with jaw deformities associated with facial asymmetry.     

Second premolar agenesis is associated with mandibular form:a geometric morphometric analysis of mandibular cross-sections

The aim of this study was to compare mandibular form (i.e., size and shape) between patients with agenesis of the lower second premolar (P2) and a control group with no agenesis. Three hypotheses were tested: (H1) agenesis causes a change in mandibular morphology because of inadequate alveolar ridge development in the area of the missing tooth (mandibular plasticity); (H2) agenesis is caused by spatial limitations within the mandible (dental plasticity); and (H3) common genetic/epigenetic factors cause agenesis and affect mandibular form (pleiotropy). A geometric morphometric analysis was applied to cross-sectional images of computed tomography (CT) scans of three matched groups (n=50 each):(1) regularly erupted P2;(2) agenesis of P2 and the primary second molar in situ;and (3) agenesis of P2 and the primary second molar missing for 43 months. Cross-sections of the three areas of interest (first premolar, P2, first molar) were digitized with 23 landmarks and superimposed by a generalized Procrustes analysis. On average, the mandibular cross-sections were narrower and shorter in patients with P2 agenesis compared with that in the control group. Both agenesis groups featured a pronounced submandibular fossa. These differences extended at least one tooth beyond the agenesis-affected region. Taken together with the large interindividual variation that resulted in massively overlapping group distributions, these findings support genetic and/or epigenetic pleiotropy (H3) as the most likely origin of the observed covariation between mandibular form and odontogenesis. Clinically, reduced dimensions and greater variability of mandibular form, as well as a pronounced submandibular fossa, should be expected during the treatment planning of patients with P2 agenesis.     

Human Papillomavirus as an Independent Predictor in Oral Squamous Cell Cancer

Aim There is an increasing evidence for the role of high risk human papillomavirus （HPV） in the pathogenesis of oral squamous cell carcinoma （OSCC）. The purpose of this study is to evaluate the relevance of HPV infection to the survival and prognosis of OSCC. Methodology Fifty-two patients with OSCC were followed from 4 to 88 months with a median of 50.7 months. HPV DNA was identified in formalin-fixed, paraffin-embedded tumor specimens by nested PCR with MY09/MY11 and GP5^＋/GP6^＋ primer pairs and the HPV genotype was determined by direct DNA sequencing. Association between the HPV status and risk factors for cancer as well as tumor-host characteristics were analyzed.Survival curves were calculated by the Kaplan-Meier method and analyzed using the log-rank test. Results HPV was found in 40.4% of the tumors with HPV16 accounting for 63.5%, HPV18 for 30.8%, HPV6 for 3.9% and HPVll for 1.8%. No infection with more than one HPV genotype was detected. HPV infection was significantly associated with poor histological grade, TNM stage Ⅰ -Ⅱ, alcohol usage and no smoking status. Multivariate analysis showed that HPV had an independent prognostic effect on the overall survival after adjusting other confounding factors such as histological grade, TNM stage and tobacco usage. The presence of HPV was significantly correlated with a better survival in patients with OSCC. Conclusion HPV infection can act as an independent predictor for the survival and prognosis of OSCC.     

Comparisons of condylar movements with the functional occlusal clutch and tray clutch recording methods in CADIAX system

Aim

The purpose of this study is to compare the effects of the two clutches on recording the condylar movement.

Methodology

Ten subjects (6 women, 4 men; mean age 25.4 years) participated in the study. The mandibular movement, sagittal condylar inclination angle, and transversal condylar inclination angle of each subject were recorded with the CADIAX® using the two clutches, respectively. The characteristics of the tracings of the protrusion, opening, and mediotrusion were analyzed with the t-test statistics at α = 0.05 level. The Kappa values were calculated for an assessment of the congruence of the tracings.

Results

The results showed that the contour, direction, and dimension of the tracings in the two clutches were approximately same, but the tracings determined by the functional occlusal clutch were more regular and congruent. In the group segment recorded with the tray clutch, opening/closing paths of one subject showed crossed and time curves of three subjects appeared peak-like changes of velocity, but none were statistically different (P>0.05).

Conclusion

The research suggests that the functional occlusal clutch should be preferred in the evaluation of the mandibular function, as the tracings with the tray clutch are more likely to produce false positive results.     

The Effect of Funding Cuts on the Utilization of an Oral Pathology Diagnostic Service

Aim To examine what impact the loss of funding had on the utilization of the oral pathology service. Methodology Biopsy records were retrieved and examined in the two year period before and after the elimination of the subsidies in 2003.Results After the loss of fimding, there was a 31% decrease in the number of specimens submitted from practitioners in private practice, with the greatest drop noted in submissions from endodontists. Conclusion Despite the immediate decrease in the number of biopsies submitted after the introduction of fee-for-service, the number of specimens being submitted appears to be on the rise again, as practitioners appear to recognize the value of a specialized oral pathology diagnostic service.     

Functional Benefit after Modification of Radial Forearm Free Flap for Soft Palate Reconstruction

Objectives

To compare the velopharyngeal function, swallowing and speech of the conventional and modified radial forearm free flap (RFFF) for soft palate reconstruction.

Methods

Retrospective clinical study. Twenty-eight patients who underwent oropharyngeal reconstruction with RFFF were divided into two groups: 10 patients had conventional folded RFFF and 18 patients underwent modified method.

Results

The average speech intelligibility score in modified RFFF group was 8.0±2.4, and 6.2±2.2 in conventional RFFF group (P<0.05). The nasalance was 27.4±7.8% in modified group and 38.6±2.7% in conventional group during no nasal passage reading and 43.6±7.3% in modified group, 55.2±7.6% in conventional group during high nasal passage reading (P<0.05). The subjective swallowing functional score was 2.8 in modified group and 2.1 in conventional group.

Conclusion

The speech assessment and nasalance demonstrate a more favorable outcome in modified group than conventional group.     

Endodontic treatment: a significant risk factor for the development of maxillary fungal ball

Objectives

The risk factors for maxillary fungal ball are largely unknown. The aim of this study was to determine whether endodontic treatment of maxillary teeth is a risk factor for fungal ball development in the maxillary sinus, and to identify other possible risk factors.

Methods

One hundred and twelve case patients diagnosed with maxillary fungal ball (FB group) and age and gender matched control patients diagnosed with chronic paranasal rhinosinusitis (PNS group) were included to determine associations between previous endodontic treatment and maxillary fungal ball. In addition, we reviewed the dental extraction status of maxillary teeth and the underlying disease in both groups to analyze the other risk factors for maxillary fungal ball.

Results

There were 36.3% of patients in the FB group and 16.1% in the PNS group showed evidence of endodontic treatment on the maxillary teeth (P<0.001). Even after correction for possible confounding factor - the frequency of dental extractions - the rate of endodontic treatment remained higher in the FB group. The mean number of endodontically treated maxillary teeth in the FB group and PNS group were 0.63 and 0.27, respectively (P=0.001). In addition, 20.5% of the patients in the FB group and 13.4% in the PNS group has diabetes mellitus (P=0.154).

Conclusion

Endodontic treatment on maxillary teeth was a significant risk factor for the development of fungal balls in the maxillary sinus.     

Intersession repeatability of acoustic rhinometry measurements in healthy volunteers

Objectives

Acoustic rhinometry is a rapid, reliable and non-invasive technique for the evaluation of conditions associated with impaired nasal patency. This study aimed to examine the intersession repeatability of acoustic rhinometry measurements of unilateral and combined nasal parameters in a group of healthy volunteers.

Methods

Twenty healthy volunteers were studied. In each subject, acoustic rhinometry measurements were performed on five consecutive days, with multiple recordings. Five clinically relevant parameters were measured in each session and the intersession repeatability of these measurements was expressed in terms of mean coefficient of variation, intraclass correlation coefficient and inter-item correlations.

Results

Intraclass correlation coefficients showed a high, and greater repeatability over time for all the combined (mean) values compared to the unilateral values. All intraclass correlations for combined values were ≥0.80 confirming almost perfect agreement. All intraclass correlations and inter-item correlations were associated with P<0.001. The mean coefficient of variation was low (<10%) for all but the proximal minimum cross sectional area (MCA1) measurements.

Conclusion

Acoustic rhinometry provides highly repeatable measurements of nasal patency, which is best for combined (mean) nasal parameters. This property makes it suitable for use in the diagnosis and follow-up of conditions associated with nasal obstruction, either structural or functional.     

Fluconazole Susceptibility and Genotypic Heterogeneity of Oral Candida albicans Colonies from the Patients with Cancer Receiving Chemotherapy in China

Aim To identify heterogeneity of Candida albicans （C. albicans） isolated from the population with cancer in China by using identification medium, subculture molecular typing, and antifungal susceptibility test. Methodology Oral cheek mucosal specimens from 52 cancer patients receiving chemotherapy were cultured on CHROMagar CandidaTM plates for Candida identification. All the C. albicans colonies on the plates were subcultured and reconfirmed by API20C, then submitted to the antifimgal drug susceptibility test with fluconazole and molecular typing using randomly amplified polymorphic DNA-PCR （RAPD） with primers RSD6 and RSD12.Results 54% （28/52） patients were oral yeast carriage in which C. albicans predominated. More than 7 C. albicans colonies were isolated from each of 12 patients （Group A）, while less than 5 colonies were isolated from each of 16 patients （Group B）. RSD6 and RSD12 were successful in eliciting 17 （A1-A17） and 2 （B1-B2） genotypes, respectively from among the 205 isolates. The two primers were combined to generate 21 genotypes. The C. albicans isolates obtained from the same patient and episode showed a diversity for fluconazole revealed by MIC50 and MIC90. Conclusion The heterogeneity of the C. albicans colonies isolated from the same patients can be detected. C. albicans with varied fluconazole susceptibility and genotypic characteristics may coexist in the same oral Candida population.     

The effect of uvula-preserving palatopharyngoplasty in obstructive sleep apnea on globus sense and positional dependency

Objectives

This study investigated the outcomes of uvula-preserving palatopharyngoplasty (UPPPP) in patients with obstructive sleep apnea syndrome (OSAS).

Methods

Twenty men with obstructive sleep apnea syndrome received the UPPPP operation at our institution. We measured symptom changes after UPPPP using a visual analog scale (VAS), and all patients were examined with polysomnography pre- and post-operatively. ''Surgical success'' was defined as reduction in apnea-hypopnea index (AHI) to below 20 events per hour and more than 50% post-operative reduction.

Results

Snoring decreased significantly (6.7±2.3 to 3.7±2.9 on VAS, P=0.002) but the postoperative globus sense did not differ from that preoperatively (2.0±2.4 to 2.1±2.7 on VAS, P=0.79). Apnea and apnea-hypopnea indices were significantly reduced after UPPPP (34.7±20 to 24.2±17.2 events/hour, P=0.029). The surgical success rate was 40% regardless of Friedman stage. There was significant reduction in the AHI on supine sleep in both surgically successful and unsuccessful patient groups.

Conclusion

UPPPP may minimize postoperative globus sense and other complications, with a success rate comparable to that of previously reported surgical methods in OSAS patients. In addition, it may reduce the apnea-hypopnea index in the supine sleep position.     

Decreased Immunoreactivities and Functions of the Chloride Transporters, KCC2 and NKCC1, in the Lateral Superior Olive Neurons of Circling Mice

Objectives

We tested the possibility of differential expression and function of the potassium-chloride (KCC2) and sodium-potassium-2 chloride (NKCC1) co-transporters in the lateral superior olive (LSO) of heterozygous (+/cir) or homozygous (cir/cir) mice.

Methods

Mice pups aged from postnatal (P) day 9 to 16 were used. Tails from mice were cut for DNA typing. For Immunohistochemical analysis, rabbit polyclonal anti-KCC2 or rabbit polyclonal anti-NKCC1 was used and the density of immunolabelings was evaluated using the NIH image program. For functional analysis, whole cell voltage clamp technique was used in brain stem slices and the changes of reversal potentials were evaluated at various membrane potentials.

Results

Immunohistochemical analysis revealed both KCC2 and NKCC1 immunoreactivities were more prominent in heterozygous (+/cir) than homozygous (cir/cir) mice on P day 16. In P9-P12 heterozygous (+/cir) mice, the reversal potential (E_gly) of glycine-induced currents was shifted to a more negative potential by 50 µM bumetanide, a known NKCC1 blocker, and the negatively shifted E_gly was restored by additional application of 1 mM furosemide, a KCC2 blocker (-58.9±2.6 mV to -66.0±1.5 mV [bumetanide], -66.0±1.5 mV to -59.8±2.8 mV [furosemide+bumetanide], n=11). However, only bumetanide was weakly, but significantly effective (-60.1±2.9 mV to -62.7±2.6 mV [bumetanide], -62.7±2.6 mV to -62.1±2.5 mV [furosemide+bumetanide], n=7) in P9-P12 homozygous (cir/cir) mice.

Conclusion

The less prominent immunoreactivities and weak or absent responses to bumetanide or furosemide suggest impaired function or delayed development of both transporters in homozygous (cir/cir) mice.