Alfonso Sánchez-Ayala

Reproducibility, reliability and validity of measurements obtained from Cecile3 digital models.

The aim of this study was to determine the reproducibility, reliability and validity of measurements in digital models compared to plaster models. Fifteen pairs of plaster models were obtained from orthodontic patients with permanent dentition before treatment. These were digitized to be evaluated with the program Cécile3 v2.554.2 beta. Two examiners measured three times the mesiodistal width of all the teeth present, intercanine, interpremolar and intermolar distances, overjet and overbite. The plaster models were measured using a digital vernier. The t-Student test for paired samples and interclass correlation coefficient (ICC) were used for statistical analysis. The ICC of the digital models were 0.84 +/- 0.15 (intra-examiner) and 0.80 +/- 0.19 (inter-examiner). The average mean difference of the digital models was 0.23 +/- 0.14 and 0.24 +/- 0.11 for each examiner, respectively. When the two types of measurements were compared, the values obtained from the digital models were lower than those obtained from the plaster models (p < 0.05), although the differences were considered clinically insignificant (differences < 0.1 mm). The Cécile digital models are a clinically acceptable alternative for use in Orthodontics.

Histopathological Changes by the Use of Soft Reline Materials: A Rat Model Study

Aim To assess the histopathological changes of rat palatal mucosa exposed to soft reline materials. Methods Forty-five adult female Wistar rats with controlled living conditions and fed ad libitum were employed. Palatal appliances of heat-polymerized acrylic resin Lucitone 550 were manufactured and worn by forty animals during 14 days. Five animals did not use the appliances (G1) and were used to control the appliance influence. One experimental group (n = 10) used the appliances without any relining material (G2) to control the material effect. Three experimental groups (n = 10) received the following soft reline materials below appliances: Dentusoft (G3), Dentuflex (G4), and Trusoft (G5). Appliances from half of each experimental group(n = 5) was immersed in water bath at 55°C for 10 min before use. Animals were slaughtered and the palates were fixed in 10% buffered formalin. Hematoxylin and eosin stained sections of 5 µm were analyzed by computerized planimetry. Cellular compartment, keratin and total epithelial thickness, and basement membrane length were measured to histopathological description.Analysis of variance and Tukey post-hoc test were used to data examination(α = 0.05). Results For heat-treatment groups, G4 showed less elongated ridges at the basal layer interface (p = 0.037) than G2. When comparing the conditions with and without heat-treatment, only G2 showed a significant decrease in the cellular compartment, keratin layer and total epithelium thickness (p<0.05). Conclusion The post-polymerization for Lucitone 550 was an effective method to reduce the changes in the rat palatal mucosa. The soft reline materials tested did not cause significant histopathological changes in the rat palatal mucosa.

Nutritional effects of implant therapy in edentulous patients--a systematic review.

Purpose:The aim of this study was to present all the relevant studies that have evaluated, with valid scientific methodology, the possible physical and nutrient intake improvement of edentulous subjects rehabilitated with removable and supported or retained implant denture, without restriction of suprastructure modalities, compared with those wearing conventional removable dentures. Methods and Materials:Several electronic databases (Pubmed, Medline—Medline In-Process, Cochrane Library Database, Embase, and Lilacs) were searched, without language limitation. References from the selected articles were also hand searched. Abstracts which appeared to fulfill the initial selection criteria (comparison of nutritional state between conventional removable and supported or retained implant denture wearers) were selected by consensus and their original articles were then retrieved. Clinical trials that included anthropometric measurements or nutrient intake in removable and supported or retained implant denture wearers without syndrome and systemic influences, nor presenting surgical or other simultaneous treatment, which could affect the integrity during the evaluation period were finally selected. Results:Only 5 articles met the selection criteria. Two studies (randomized clinical trials and prospective) found inadequate nutrient intake after treatment. One randomized clinical trial presented an improvement in nutritional state after treatment. One cross-sectional study showed an adequate nutritional state before and after treatment. These 4 studies found no significant difference between implant and conventional treatments. Finally, 1 cross-sectional study presented a difference between treatments, showing that the risk of malnutrition was higher for removable complete denture wearers. Conclusion:Considering the available evidence, the effect on the nutritional state in edentulous subjects treated with implant therapy is similar to the 1 obtained with conventional removable dentures. This effect does not necessarily mean an optimum nutritional state, which also depends on other factors not related to prosthodontic treatment.

Relationship between Body Fat and Masticatory Function

PURPOSE The aim of this cross-sectional study was to investigate the relationship between body fat and masticatory function. MATERIALS AND METHODS One hundred dentate and partially edentulous participants (33 male; mean age, 39.7 ± 16.6 years) were selected. Body fat was established through body mass index (BMI). Masticatory function was evaluated by quantifying occlusal pairs and determining masticatory efficiency and swallowing threshold with the sieving method. During the swallowing threshold test, chewing rate was registered. Masticatory ability was also evaluated with a 5-point Likert scale questionnaire. Data were analyzed with Spearman and chi-square tests, as well as binary logistic regression analysis for the presence of increased BMI (α= 0.05). RESULTS Age (rho = 0.517), occlusal pairs (chi-square = 26.353), masticatory efficiency (chi-square = 30.935), masticatory ability (chi-square = 25.132; p < 0.001), and swallowing threshold (chi-square = 8.730; p < 0.005) were related to BMI. Age (odds ratio, OR = 1.048, 95% CI = 1.008 to 1.089) and lower masticatory efficiency (OR = 4.792, 95% CI = 1.419 to 16.183) were predictive of increased body fat (p < 0.05). Gender (chi-square = 0.402, p= 0.526) and chewing rate (rho =-0.158, p= 0.117) were not related to BMI. CONCLUSIONS These results suggest that people with lower masticatory efficiency may be at risk for increased body fat.

Relationship Between Chewing Rate and Masticatory Performance

Abstract The influence of mandibular movement timing on food breakdown remains unclear. The authors, therefore, sought to relate chewing rate with masticatory performance. Chewing rate, defined as the number of masticatory cycles habitually achieved per minute, was measured in 55 healthy dentulous subjects (age, 22.2±5.0 years). Subjects were grouped according to obtained values (cycles/minute): slower: <70; middle: 70-90; and faster: >90. Masticatory performance was determined through the sieve method, and the estimated comminuted median particle size (X50). Data was analyzed using the one-way ANOVA and chi-square tests (α=.05). Subjects with slower chewing rates showed higher (p<.05) masticatory performance (X50 = 3.05±0.77 mm). X50 was associated with chewing rate when subjects were categorized as better or poorer performers (chi-square=11.25, p<.005). Thus, chewing rate was related to masticatory performance, with smaller food particles being achieved with a slower chewing rate.

Marginal microleakage of class V resin-based composite restorations bonded with six one-step self-etch systems

This study compared the microleakage of class V restorations bonded with various one-step self-etching adhesives. Seventy class V resin-based composite restorations were prepared on the buccal and lingual surfaces of 35 premolars, by using: Clearfil S3 Bond, G-Bond, iBond, One Coat 7.0, OptiBond All-In-One, or Xeno IV. The Adper Single Bond etch-and-rinse two-step adhesive was employed as a control. Specimens were thermocycled for 500 cycles in separate water baths at 5°C and 55°C and loaded under 40 to 70 N for 50,000 cycles. Marginal microleakage was measured based on the penetration of a tracer agent. Although the control showed no microleakage at the enamel margins, there were no differences between groups (p = 0.06). None of the adhesives avoided microleakage at the dentin margins, and they displayed similar performances (p = 0.76). When both margins were compared, iBond® presented higher microleakage (p < 0.05) at the enamel margins (median, 1.00; Q3-Q1, 1.25-0.00) compared to the dentin margins (median, 0.00; Q3-Q1, 0.25-0.00). The study adhesives showed similar abilities to seal the margins of class V restorations, except for iBond®, which presented lower performance at the enamel margin.

Relationship between non-ulcerative functional dyspepsia, occlusal pairs and masticatory performance in partially edentulous elderly persons

OBJECTIVE To relate occlusal state, masticatory performance and non-ulcerative functional dyspepsia. BACKGROUND In spite of the relationship between gastric disturbances and number of present teeth being recognised, the influence of the number of occlusal pairs and masticatory performance, expressed as median particle size, has not been considered. MATERIALS AND METHODS Thirty-eight subjects (mean age = 71.8 ± 7.7 years) diagnosed with non-ulcerative functional dyspepsia were selected. A further 38 healthy subjects (mean age = 71.9 ± 7.0 years) acted as controls. Subjects were subdivided according to their number of occlusal pairs: (1) 0-4, (2) 5-9 and (3) 10-14. Masticatory performance was evaluated by using the sieving method. Data were analysed using 2-way anova and Bonferroni post-hoc, Chi-square and Odd ratio tests. RESULTS Subjects presenting with non-ulcerative functional dyspepsia and 0-4 occlusal pairs showed the lowest masticatory performance (p < 0.01). No association between the dyspepsia and the number of occlusal pairs (χ(2) = 0.48, p = 0.785) was observed, however results showed association between functional dyspepsia and masticatory performance (χ(2) = 4.07, p = 0.0437) presenting an odds ratio = 3.46 (Confidence Interval = 0.99-12.10). CONCLUSION Changes in masticatory performance were associated with the presence of non-ulcerative functional dyspepsia.

Relationship among malocclusion, number of occlusal pairs and mastication.

This study evaluated the relationship among malocclusion, number of occlusal pairs, masticatory performance, masticatory time and masticatory ability in completely dentate subjects. Eighty healthy subjects (mean age = 19.40 ± 4.14 years) were grouped according to malocclusion diagnosis (n = 16): Class I, Class Class II-2, Class III and Normocclusion (control). Number of occlusal pairs was determined clinically. Masticatory performance was evaluated by the sieving method, and the time used for the comminute test food was registered as the masticatory time. Masticatory ability was measured by a dichotomic self-perception questionnaire. Statistical analysis was done by one-way ANOVA, ANOVA on ranks, Chi-Square and Spearman tests. Class II-1 and III malocclusion groups presented a smaller number of occlusal pairs than Normocclusion (p < 0.0001), Class I (p < 0.001) and II-2 (p < 0.0001) malocclusion groups. Class I, and III malocclusion groups showed lower masticatory performance values compared to Normocclusion (p < 0.05) and Class II-2 (p < 0.05) malocclusion groups. There were no differences in masticatory time (p = 0.156) and ability (χ² = 3.58/p= 0.465) among groups. Occlusal pairs were associated with malocclusion (rho = 0.444/p < 0.0001) and masticatory performance (rho = 0.393/p < 0.0001), but malocclusion was not correlated with masticatory performance (rho = 0.116/p= 0.306). In conclusion, masticatory performance and ability were not related to malocclusion, and subjects with Class I, II-1 and III malocclusions presented lower masticatory performance because of their smaller number of occlusal pairs.

The effect of posterior tooth loss on the expression of type II collagen, IL-1β and VEGF in the condylar cartilage of growing rats

OBJECTIVE The aim of this study was to evaluate the effect of unilateral and bilateral loss of posterior occlusal support on the expression of type II collagen, interleukin-1β and VEGF in the condylar cartilage of growing rats. DESIGN Thirty female Wistar rats (5 weeks old) were randomized into three groups: control, unilateral extraction of mandibular molar teeth, bilateral extraction of mandibular molar teeth. Animals were sacrificed 8 weeks after tooth extraction and the temporomandibular joints were prepared for immunohistochemical analysis. RESULTS Bilateral molar extraction increased the expression of interleukin-1β (P<0.01) and VEGF (P<0.01), while unilateral extraction increased the expression of interleukin-1β (P<0.05) and type II collagen (P<0.01). The expression of VEGF was higher on the extracted than on the non-extracted side (P<0.01) after unilateral extraction. CONCLUSION Loss of posterior occlusal support alters the expression of type II collagen, interleukin-1β and VEGF in the condylar cartilage of rats. The expression pattern of these proteins is different when loss of occlusal support was bilateral or unilateral, including differences between extracted and non-extracted sides.

A Survey of the Management of Patients with Temporomandibular Disorders by General Dental Practitioners in Southern Brazil.

PURPOSE Temporomandibular disorders (TMD) are recognized as one of the most controversial topics in dentistry, despite the fact that both basic science and clinical researchers have currently reached some degree of consensus. This study aimed to conduct a questionnaire-based survey about the management of TMD patients by general dental practitioners (GDPs). MATERIALS AND METHODS One hundred fifty-one GDPs with a private practice in a city of southern Brazil were included, independent of school of origin, gender, graduation year, and curriculum content. All participants were administered a questionnaire about the management of patients with TMD, and the responses were analyzed by binomial and chi-square tests (α = 0.05). RESULTS Of the GDPs, 88.7% received TMD patients, who were primarily diagnosed on the basis of medical history (36.6%) or physical examination (30.4%). Of these, 65.4% referred the patients elsewhere, primarily to specialists in occlusion (36.1%) or orthodontics (29.7%). Occlusal splinting was the most commonly used management modality (20.8%), followed by occlusal adjustment (18.1%) and pharmacotherapy (16.6%). Splints were fabricated in maximum habitual intercuspation or centric relation depending on individual patient (54.8%). The hard stabilization form was the most common type of appliance used (35.0%). Moreover, 73.8% of the GDPs did not employ semi-adjustable articulators, and 69.5% adjusted the appliances at the time of fixing. The duration of splint use and the frequency of follow-up were considered patient dependent by 62.1% and 72.8%, respectively. GDPs considered the two major TMD etiologic categories as multifactorial (20.8%) and occlusion (19.9%). Multidisciplinary medical and dental treatment was considered necessary by 97.9%. CONCLUSIONS The evaluated general dental practitioners manage TMD patients according to international guidelines.