The recent literature on maxillary implant overdenture (IOD) was reviewed in order to clarify its predictability and establish treatment guidelines. Electronic searches were performed using PubMed, and articles about maxillary IOD written after 1990 were reviewed, focusing on the following items: I. implant survival rate, II. maxillary IOD survival rate, III. number of implants, IV. attachment type, V. follow-up period, VI. implant system, and VII. opposing dentition. The review revealed an implant survival rate of 61-100% and an overdenture survival rate of 72.4-100%. The attachments used included bars, balls, locators, and telescope crowns. The minimum and maximum observation periods were 12 months and 120 months, respectively, and the number of implants used for supporting IOD ranged from 2 to 8. At present, there is no strong evidence to indicate that maxillary IOD is clearly superior for all the items examined. However, the existing data indicate that maxillary IOD has almost the same therapeutic effect as fixed implant superstructures, and is a treatment option that can be actively adopted for patients in whom fixed superstructures cannot be applied for various reasons.
Purpose: This study compared the removability of AH Plus and EndoSequence BC sealers using in vitro micro-computed tomography.
Methods: Ten single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size X5 (50/0.06) (Dentsply-Sirona). Canals were obturated with a single cone gutta-percha and either AH Plus (Dentsply-Sirona) (Group A) or EndoSequence BC (Brasseler) (Group B). ProTaper Universal Retreatment files (Dentsply-Sirona) were used to remove obturation materials after 90 days at 37oC/100% humidity. Each tooth was scanned using micro-computed tomography (SkyScan 1272; Bruker) at an isotropic resolution of 6 μm from which the percent of material removed was calculated. Two-sample t-tests and one-way ANOVA were used for analysis.
Results: The percent removal of materials in the coronal third was 92.9% ± 7.3% (Group A) and 93.2% ± 6.1% (Group B). Removal in the middle third was 94.9% ± 8.5% (Group A) and 96.5% ± 6.1% (Group B). Apical third removal was 76.2% ± 27.9% (Group A) and 70.1% ± 30.8% (Group B). No statistically significant differences were determined between the two sealers or among the sectional thirds within each group (P > 0.05).
Conclusion: AH Plus and EndoSequence BC sealers exhibit the same removability at all canal levels of 70% to 96%, with better removal coronally.
Purpose: This study aims to delve deeper into the hypothesis that normal salivary gland tissue expresses both protein and mRNA of mammaglobin (MGB).
Methods: Formalin-fixed paraffin-embedded samples of submandibular (10), parotid (5), palatal (5) and labial glands (30) salivary glands were immunohistochemically investigated. The labial samples were used to examine the MGB positive ratio (MGB-PR), and localize MGB by double immunofluorescence staining and quantitative mRNA gene expression. Mann-Whitney U and Kruskal Wallis rank-sum test for group comparison, and Spearman’s rank correlation coefficient for correlation analysis were used.
Results: The distribution of MGB-positive cells was variable throughout samples with significantly higher MGB-PR of acini than ducts (P = 0.00376), and there was no difference when compared based on age (P = 0.0646) and gender (P = 0.245). Besides acinar cells, a number of myoepithelial cells and ductal cells also demonstrated strong MGB reactivity with varying MGB mRNA expression levels in 6 of the 7 samples (with MGB-PR > 20%) tested.
Conclusion: This novel study shows that unlike aberrant protein expression in some carcinomas, MGB expression in salivary gland neoplasms represents the nature of original cells, giving a better insight into the neoplasms expressing MGB.
Purpose: To study effects of bioactive glass with high phosphorus content (10.8% P2O5, 54.2% SiO2, 35% CaO, mol%, named PSC) on mineralization of type I collagen fibrils.
Methods: (1) PSC, and PSC combining 0.1 mg/mL, 0.5 mg/mL, or 1.0 mg/mL polyacrylic acid (PAA), were used to induce the mineralization of self-assembled type I collagen fibrils. After 3 and 7 days of mineralization, collagen fibrils were observed by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). (2) PSC suspension was dialyzed in simulated body fluid (SBF), or in SBF containing 0.1 mg/mL, 0.5 mg/mL, or 1.0 mg/mL PAA, to form amorphous calcium phosphate (ACP), then observed by TEM.
Results: (1) PSC and PSC combining 0.1 mg/mL or 0.5 mg/mL PAA induced mainly extrafibrillar mineralization. PSC combining 1.0 mg/mL PAA induced both extrafibrillar and intrafibrillar mineralization. (2) The ACP induced by PSC or PSC combining 0.1 mg/mL PAA partly formed lattice structure after 24 h. The particle size of the ACP induced by PSC combining 0.5 mg/mL PAA was 100-150 nm, and that induced by PSC combining 1.0 mg/mL PAA was 30-50 nm.
Conclusion: PSC induced mainly extrafibrillar mineralization, and PSC combining an appropriate concentration (1.0 mg/mL) of PAA induced both extrafibrillar and intrafibrillar mineralization.
Purpose: The aim of this study was to investigate and compare the effects of some whitening toothpastes on the surface roughness and coloration susceptibility of a composite resin, as well as their whitening effectiveness.
Methods: This study was carried out in two different stages. In experiment A, samples were divided into 7 subgroups to compare the surface roughness and coloration susceptibility of the composite resin: distilled water, conventional toothpaste, and 5 different whitening toothpastes. In experiment B, samples were divided into 8 subgroups to compare the whitening effectiveness of the whitening toothpastes: conventional toothpaste, 5 other whitening toothpastes, and two bleaching groups. After toothbrushing simulation, the color and surface roughness of the samples were measured. Data were subjected to one-way analysis of variance, paired t-test and Tukey post-hoc test (α = 0.05).
Results: There were no statistically significant differences among the surface roughness values for the groups for any period before and after brushing (P > 0.05). In terms of the coloration susceptibility of the composite resin and the whitening effects of the toothpastes, no statistically significant differences were evident among the groups for any period before and after brushing (P > 0.05).
Conclusion: The results of this study indicate that effective toothbrushing is more important than the type of toothpaste employed.
Purpose: This study evaluated the effect of progressive training on the oral health behaviors of dental students from Switzerland and Brazil.
Methods: Dental students from two dental schools (in Zurich, Switzerland, and Goiania, Brazil) were recruited for this study. Dental behaviors of the students in the final 3 years of their 5-year dental curriculum were assessed with the 20-item Hiroshima University-Dental Behavior Inventory (HU-DBI). Nonparametric tests were used to assess intergroup and intragroup differences (significance level: α = 0.05).
Results: 190 students (Zurich: n = 121, mean age ± SD = 25.5 ± 4.5 years; Goiania: n = 69, mean age ± SD = 23.5 ± 2.9 years) of a possible 277 students completed the survey (response rate = 68.6%). The overall mean HU-DBI score was 8.16 ± 1.35 (8.02 ± 1.27 in Switzerland and 8.41 ± 1.47 in Brazil). Age (P = 0.225) and sex (P = 0.145) were not associated with the scores, but the respondent’s nationality seemed to play a role (P = 0.024). Progressive training had no effect on the scores (P = 0.766).
Conclusions: The present findings show that progressive training has no effect on the oral health behaviors of dental students but the nationality might be a factor.
Purpose: To evaluate masticatory performance (MP), maximum occlusal force (MOF), maximum tongue pressure (MTP) and oral diadochokinesis (ODK) among community-dwelling elderly patients without posterior occlusal support.
Methods: This study enrolled community-dwelling elderly patients (≥65 years old) who belonged to Eichner A, B4, C1, C2, and C3. Each oral function was statistically compared among groups. Correlations between MP and other variables were examined in Eichner B4 and C patients.
Results: MP and MOF values in Eichner B4 and C patients were significantly lower than in Eichner A patients. There were significant differences in MTP values between Eichner “A and C2, C3”, and “B4 and C2, C3”. ODK in Eichner C patients showed significantly lower values compared to Eichner A patients in general. Although there were statistically significant correlations of MP with age, the number of remaining teeth and all oral functions were identified, and multiple regression analysis indicated that MOF and MTP were independently related to MP.
Conclusion: Oral functions in Eichner B4 and C patients were lower compared to Eichner A patients. MP was significantly correlated with MOF and MTP in elderly patients without posterior occlusal support, suggesting the importance of rehabilitation of MOF and MTP in MP.
Purpose: In order to promote osseointegration and shorten the healing time after dental implant operations, this study was conducted to develop a chair-side plasma treatment system in which Ti implants were used as a coaxial internal electrode to rapidly enhance their surface hydrophilicity.
Methods: Surface hydrophilicity was evaluated by measurement of the water contact angle and the defined wetting time. Changes in temperature and chemical composition were analyzed using infrared thermal imaging and X-ray photoelectron spectroscopy (XPS), respectively. The biocompatibility of the treated implants was examined in an animal experiment.
Results: A marked improvement of hydrophilicity was demonstrated by a decrease in the water contact angle of the treated implant to 0° and wetting of the whole surface within 3 s of water contact. The Ti implant hydrophilization mechanism was explained as a decrease in the degree of hydrocarbon contamination. The surface temperature of the treated implant was close to that of the human body, and good osseointegration was observed in the in vivo experiment.
Conclusion: The plasma treatment system developed here is a promising chair-side procedure for rapidly enhancing the surface hydrophilicity of Ti implants in clinical operations without any need to consider the degradation of hydrophilicity caused by long-term storage.
Purpose: This study aimed to determine expressions of hepatocyte growth factor (HGF) and MET proto-oncogene receptor tyrosine kinase (MET) in palatal periosteum (PP) and to examine the effect of HGF/MET on osteogenic differentiation of human palatal periosteum-derived mesenchymal stem cells (PD-MSCs).
Methods: HGF/MET proteins in human palatal periosteum (n = 3) were localized using immunohistochemistry. PD-MSCs (n = 3) were cultured in serum-free Essential 8 (E8) medium or osteogenic medium with and without Capmatinib, a selective ATP-inhibitor of MET. HGF concentration in vitro was measured with ELISA. Relative gene expression was quantified from PD-MSCs by quantitative reverse transcription real-time polymerase chain reaction.
Results: Immunohistochemistry detected co-localization of HGF and MET protein in PP. HGF protein levels were significantly higher (P < 0.05) in osteogenic media (day 21: 12.19 ± 8.36 ng/mL) than in E8 medium (day 21: 0.42 ± 0.72 ng/mL). MET inhibitor had a limited feedback effect on the expression profile of the osteogenic genes tested. Gene expression levels for all but three genes were comparable in serum-free and osteogenic media at all time points.
Conclusion: HGF/MET present in human PP and HGF is upregulated in vitro during osteogenesis; however the targeted pathways controlled by MET may not involve osteoblast maturation.
Purpose: To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in primary molars.
Methods: Occluso-mesial cavities in second primary artificial molars were randomly restored using different materials (Filtek Z500 or Filtek Bulk Fill composites or high-viscosity glass ionomer cement Ketac Universal) and different matrix system (Tofflemire, AutoMatrix, matrix band with ring, contoured sectional matrix) (n = 12). Proximal contact tightness was measured using a custom-made device in an Instron 3345, and proximal surface morphology and marginal adaptation were scored after digital scanning. Two-way ANOVA, Tukey and Fischer’s exact tests were performed (P < 0.05).
Results: Proximal contact tightness values were significantly influenced by the restorative material (P < 0.05), the matrix system (P < 0.001), and their interaction (P < 0.01). Both resin composites showed statistically differences in proximal shape according to the matrix used to restore and exhibited overhanging margins. Ketac Universal restorations showed similar morphology and gaps on the margins regardless of the matrix system.
Conclusions: Overall, both composite restorations achieved tighter proximal contact than those restored with the high-viscosity glass ionomer cement. None of the matrix systems tested provided a convex seamless proximal morphology.
Injection phobia and dental anxiety can, in severe cases, lead to avoidance of necessary treatment. The aim of this pilot study was to investigate self-reported injection phobia and dental anxiety among individuals with tattoos and/or piercings. The Injection Phobia Scale-Anxiety (IPSA) short form and the Modified Dental Anxiety Scale (MDAS) questionnaires were applied. Both the total IPSA and MDAS scores were significantly higher for individuals with tattoos in comparison with a control group (P < 0.001), suggesting a need for anxiety-reducing measures and facilitated treatment for this group of patients.
The aim of this study was to assess the effectiveness of laser acupuncture and intravascular laser irradiation of blood (ILIB) for managing anxiety in pediatric dentistry. Eighty-four children recruited at a university dental clinic were randomly assigned to three groups: the Sham group (n = 27) underwent sham laser irradiation of three acupuncture points, the ILIB group (n = 25) underwent 10 min of ILIB, and the laser acupuncture group (LAC, n = 32) underwent 40 s of laser acupuncture over points VG20 (Baihui), PC6 (Neiguan), and the Oppression Point. The results suggest that ILIB and laser acupuncture are feasible alternatives for managing dental anxiety in children.
Introducing new technology in the dental school curriculum may face some uphill challenges navigating through university-level bureaucracy, financial ramifications, and influencing the mindset of certain faculty. A dental school that relies heavily on teaching traditional restorative procedures may particularly face many challenges to embrace new technology. The restorative department at a US dental school created a division of computer-aided design and computer-aided manufacturing (CAD/CAM) dentistry to introduce the concept of digital dentistry to dental students and faculty. This article describes methods that were adopted to improve acceptance and increase the productivity of chairside CAD/CAM restorations for both students and faculty at the dental school in US.