Evaluation of trabecular bone changes according to the type of prosthesis in patients using bisphosphonates: a retrospective study.

The objective of the study was to retrospectively compare the fractal size values calculated in the trabecular bone according to the type of complete removable denture, removable partial denture, and partial fixed prosthesis between patients using bisphosphonates and healthy patients, retrospectively. Panoramic radiographs of a total of 200 patients, (100 using bisphosphonates,100 control group), were taken from the right and left molar regions before and after treatment with 72 × 72 pixels. The fractal dimension (FD) was computed by using ImageJ Software using the box-counting method on the images obtained. There was an interaction effect between the trabecular bone change-patient group-the type of prosthesis used and the parameters of the area (p < 0.05). In patients using complete removable dentures and removable partial dentures in the maxilla and mandibula in the molar region, a greater decrease in FD values was observed in the control group than in the patient group using bisphosphonates. An increase in FD values over time was observed in the patient group using bisphosphonates with partial fixed maxillary and mandibular prostheses compared to the control group. Partial fixed prostheses should be preferred primarily instead of complete removable or removable partial dentures in patients using bisphosphonates to prevent osteonecrosis due to dental trauma.

Evaluation of trabecular bone changes according to the type of prosthesis in patients using bisphosphonates: a retrospective study

Abstract The objective of the study was to retrospectively compare the fractal size values calculated in the trabecular bone according to the type of complete removable denture, removable partial denture, and partial fixed prosthesis between patients using bisphosphonates and healthy patients, retrospectively. Panoramic radiographs of a total of 200 patients, (100 using bisphosphonates,100 control group), were taken from the right and left molar regions before and after treatment with 72 × 72 pixels. The fractal dimension (FD) was computed by using ImageJ Software using the box-counting method on the images obtained. There was an interaction effect between the trabecular bone change-patient group-the type of prosthesis used and the parameters of the area (p < 0.05). In patients using complete removable dentures and removable partial dentures in the maxilla and mandibula in the molar region, a greater decrease in FD values was observed in the control group than in the patient group using bisphosphonates. An increase in FD values over time was observed in the patient group using bisphosphonates with partial fixed maxillary and mandibular prostheses compared to the control group. Partial fixed prostheses should be preferred primarily instead of complete removable or removable partial dentures in patients using bisphosphonates to prevent osteonecrosis due to dental trauma.

Combined approach to treatment of advanced stages of medication-related osteonecrosis of the jaw patients / Abordagem combinada para o tratamento de estágios avançados de osteonecrose da mandíbula relacionada a medicamentos

Abstract Introduction: Increased incidence of localized osteonecrosis in the jaw bones caused by bisphosphanate use and reduced quality of life of the patients led researchers to diagnose the disease in the early period and to investigate the effective treatment modality. Objective: Treatment of medication-related osteonecrosis of the jaw patients is based on individual protocols from clinical experience, as there are no definitive treatment guidelines. In view of the lack of consensus on the effectiveness of medication-related osteonecrosis of the jaw treatments in the literature, the aim of this study was to evaluate the surgical technique described in the treatment of advanced stages of medication-related osteonecrosis of the jaw patients. Methods: Twenty-one patients affected by Stage 2-3 medication-related osteonecrosis of the jaw were treated with ultrasonic piezoelectric bone surgery for necrotic bone removing, leukocyte and platelet-rich fibrin concentrate obtained from the patient's peripheral blood and Nd:YAG laser for biostimulation. Success was assessed as the maintenance of full mucosal coverage without signs of residual infection at 1-month (T1), 3-months (T2), 6-months (T3) and 1-year (T4) after surgery. Logistic regressions were used to evaluate the association between the different independent variables and treatment outcomes. Results: Two Stage 3 patients had delayed healing at 1 month after the operation. Complete mucosal healing was achieved in all patients at the third month. Multivariate analysis demonstrated that different variables were not significantly correlated with delayed healing (p>0.05). Conclusion: The surgical protocol presented in this study shows promising results for surgical management of advanced stages of medication-related osteonecrosis of the jaw patients. HIGHLIGHTS Removal of necrotic bone is important in the treatment of medication- related osteonecrosis of the jaw. Surgical treatment is more successful than conservative treatment in advanced stages (stage 2-3) of the medication- related osteonecrosis of the jaw. Relatively less invasive and supportive treatments are recommended in patients with advanced medication- related osteonecrosis of the jaw. Patient follow-up, good oral hygiene and patient motivation increase the success rate of the treatment.

Resumo Introdução: O aumento da incidência de osteonecrose localizada nos ossos da mandíbula causada pelo uso de bisfosfonatos e a redução da qualidade de vida dos pacientes levaram os pesquisadores a diagnosticar a doença em período inicial e a investigar a modalidade de tratamento eficaz. Objetivo: O tratamento de pacientes com osteonecrose da mandíbula relacionada a medicamentos é baseado em protocolos individuais de experiência clínica, uma vez que não há diretrizes de tratamento definitivas. Considerando a falta de consenso sobre a eficácia dos tratamentos de osteonecrose da mandíbula relacionada a medicamentos na literatura, o objetivo deste estudo foi avaliar a técnica cirúrgica descrita no tratamento de estágios avançados nesses pacientes. Método: Vinte e um pacientes com osteonecrose da mandíbula relacionada a medicamentos estágio 2-3 foram tratados com cirurgia óssea piezelétrica ultrassônica para remoção de osso necrótico, concentrado de leucócitos e fibrina rica em plaquetas obtido do sangue periférico do paciente e laser Nd: YAG para bioestimulação. O sucesso foi avaliado pela manutenção da cobertura total da mucosa sem sinais de infeçcão residual em um mês (T1), 3 meses (T2), 6 meses (T3) e um ano (T4) após a cirurgia. Regressões logísticas foram usadas para avaliar a associação entre as diferentes variáveis independentes e os resultados do tratamento. Resultados: Em dois pacientes no Estágio 3, a cicatrização foi tardia em um mês após a cirurgia. A cicatrização completa da mucosa foi obtida em todos os pacientes no terceiro mês. A análise multivariada demonstrou que diferentes variáveis não se correlacionaram significativamente com o retardo da cicatrização (p > 0,05). Conclusão: O protocolo cirúrgico apresentado neste estudo mostra resultados promissores para o manejo cirúrgico de estágios avançados de pacientes com osteonecrose da mandíbula relacionada a medicamentos. DESTAQUES A remo¸cão do osso necrótico é importante no tratamento de osteonecrose da mandíbula relacionada a medicamentos. O tratamento cirúrgico é mais bem-sucedido do que o tratamento conservador em estágios avançados (estágio 2-3) de osteonecrose da mandíbula relacionada a medicamentos. Tratamentos relativamente menos invasivos e de suporte são recomendados em pacientes com osteonecrose avançada da mandíbula relacionada a medicamentos. O seguimento do paciente, uma boa higiene oral e a motivação do paciente aumentam a taxa de sucesso do tratamento.

Fatigue and Stress Distribution Analyses of Ceramic-Reinforced PEEK Abutments Restored with Monolithic Zirconia Crowns as an Alternative to Conventional Esthetic Abutments.

PURPOSE: To determine the fracture strength and stress distribution of esthetic dental implant abutments. MATERIALS AND METHODS: Fifty specimens were prepared. Four hybrid abutment groups with titanium bases (zirconia [Z], lithium disilicate [L], ceramic-reinforced polymer [B] and [BC]) and a custom titanium abutment control group (T) were restored with monolithic zirconia crowns except BC, which was crowned with layered composite. Ceramic abutments were cemented on Ti bases with a self-curing resin cement. Polymer abutments were cemented on Ti bases with an adhesive resin cement. All crowns for T, Z, and L were cemented with another self-adhesive resin cement, while the B and BC groups were cemented with the same adhesive resin cement for the polymer. Fatigue testing was performed by a chewing simulator (CS-4.2, SD, 50 N, 240,000 cycles) followed by fracture strength testing (0.5 mm/min, 5,000 N). Failure type analysis was made by a stereomicroscope. Statistical analyses were made (SPSS 25.0, analysis of variance [ANOVA], Tukey honestly significant difference [HSD], 95% CI). Complementary finite element analyses (FEAs) were performed (Algor Fempro). RESULTS: Mean ± SD fracture strengths for T, Z, L, B, and BC were 1,522.67 ± 190.77, 1,207.76 ± 89.03, 818.81 ± 109.96, 1,126.23 ± 142.23, and 899.08 ± 60.36, respectively (P < .05). Abutment screw flexure and/or cracks or crown material fractures for T, Z, L, and B occurred, while no implant and/or abutment fractures were observed for BC except for crown fracture and Ti base flexure. FEA exhibited similar stress concentrations. CONCLUSION: Monolithic zirconia crowns on titanium abutments and hybrid zirconia abutments exhibited the highest fracture strengths. Lithium disilicate and BioHPP abutments had the lowest fracture strength, while no fractures were observed on the implant, abutment, or screw.

Combined approach to treatment of advanced stages of medication-related osteonecrosis of the jaw patients.

INTRODUCTION: Increased incidence of localized osteonecrosis in the jaw bones caused by bisphosphanate use and reduced quality of life of the patients led researchers to diagnose the disease in the early period and to investigate the effective treatment modality. OBJECTIVE: Treatment of medication-related osteonecrosis of the jaw patients is based on individual protocols from clinical experience, as there are no definitive treatment guidelines. In view of the lack of consensus on the effectiveness of medication-related osteonecrosis of the jaw treatments in the literature, the aim of this study was to evaluate the surgical technique described in the treatment of advanced stages of medication-related osteonecrosis of the jaw patients. METHODS: Twenty-one patients affected by Stage 2-3 medication-related osteonecrosis of the jaw were treated with ultrasonic piezoelectric bone surgery for necrotic bone removing, leukocyte and platelet-rich fibrin concentrate obtained from the patient's peripheral blood and Nd:YAG laser for biostimulation. Success was assessed as the maintenance of full mucosal coverage without signs of residual infection at 1-month (T1), 3-months (T2), 6-months (T3) and 1-year (T4) after surgery. Logistic regressions were used to evaluate the association between the different independent variables and treatment outcomes. RESULTS: Two Stage 3 patients had delayed healing at 1 month after the operation. Complete mucosal healing was achieved in all patients at the third month. Multivariate analysis demonstrated that different variables were not significantly correlated with delayed healing (p > 0.05). CONCLUSION: The surgical protocol presented in this study shows promising results for surgical management of advanced stages of medication-related osteonecrosis of the jaw patients.

Evaluation of 3D Face-Scan images obtained by stereophotogrammetry and smartphone camera.

OBJECTIVE: The purpose of this study is to compare and analyze the similarities between three-dimensional images captured by a smartphone camera with depth sensors and a conventional 3dMD Face system. MATERIALS AND METHODS: Twenty six individuals (16 female, 10 male) were involved in this study, agreed to take part and as such had no paralysis, tics, etc., which may prevent taking the image. Anthropometric points were marked, and plasters were placed on the forehead, upper nasal dorsum and zygoma to determine matching areas. 3D images were captured with a DOF (Depth of Field) camera of a smartphone (iPhone X, Apple Inc. CA, USA) and a 3D imaging system (3dMD, Atlanta, GA, USA). Linear and angular measurements were carried. Overlapping area amounts of matched images and X, Y and Z coordinates of landmarks were compared. For comparison of the data, student t-test and Mann-Whitney U test were used at P<0.05. RESULTS: Statistically significant changes were found in distance between inner commissures of right and left eye fissure and nasolabial angle. RMS (Root Mean Square) values were found between 0.58 and 1. CONCLUSION: Images captured with a DOF camera of a smartphone, can be used to record and evaluate 3D soft tissue changes. However, due to the anatomical features of some regions, the deficiency of clear visualization needs improvements.

Radiographic determination of trabecular bone change in 2- and 4-implant-supported overdenture prostheses.

OBJECTIVE: The aim of this study was to compare the fractal dimensions (FDs) of peri-implant trabecular bone around 2-implant-supported overdentures with the FDs around 4-implant-supported overdentures at the time of implant placement (T0) and 1 year after placement (T1). STUDY DESIGN: Standardized regions of interest were chosen at sites mesial and distal to 60 mandibular implants: 20 in 2-implant-supported prostheses (group 1) and 40 in 4-implant-supported prostheses (group 2), for a total of 120 measurements. FD values were calculated by using ImageJ software with the box-counting method. RESULTS: The mean FD values of peri-implant bone were significantly lower at T1 than at T0 in both groups (P ≤ .001). Differences between the groups in the decrease in FD between T0 and T1 were mostly insignificant. CONCLUSIONS: Within the limitations of this study, 2-implant and 4-implant-supported overdentures exhibited the same degree of reduction in peri-implant FD over time, suggesting similar risk of failure because FD is related to implant stability. Depending on the patient's residual ridge status and other factors, the 2-implant-supported overdenture may be preferred because it requires less surgery and is less costly.

Radiographic Evaluation of Infraorbital Canal Protrusion into Maxillary Sinus Using Cone-Beam Computed Tomography.

OBJECTIVES: The aim of this retrospective study was to evaluate the relation of the infraorbital canal course with the maxillary sinus using cone-beam computed tomography. MATERIAL AND METHODS: A total of 1000 infraorbital canals (IOC) were examined from 500 cone-beam computed tomography scans. IOCs were classified into three types based on the degree of protrusion into the sinus. The presence of Haller cells and mucosal thickening in the sinus were evaluated. The length of bony septum from the canal to the sinus wall (D1), the distance at which protrusion begins posterior to the inferior orbital rim (D2), the vertical distance from the canal to the sinus roof (D3), and the vertical distance from the canal to the sinus floor (D4) were measured. RESULTS: The prevalence of IOC protrusion into the sinus was 8.8%. There was a significant difference in the prevalence of Haller cells between IOC types (P < 0.01). However, no significant correlation was found between IOC types and the presence of mucosal thickening (P > 0.05). There was no significant difference in the mean D1, D2, and D3 between the genders (P > 0.05). The mean D4 was significantly higher in males than in females (P < 0.05). CONCLUSIONS: The protrusion of infraorbital canals into the sinus is a common variation that must be considered to prevent accidental injury. Our findings suggest that the risk of injury to the descending canals is very low during routine dentoalveolar procedures because the protruded canal is not close to the sinus floor.

In vivo wear determination of novel CAD/CAM ceramic crowns by using 3D alignment.

PURPOSE: To determine wear amount of single molar crowns, made from four different restoratives, and opposing natural teeth through computerized fabrication techniques using 3D image alignment. MATERIALS AND METHODS: A total of 24 single crowns (N = 24 patients, age range: 18 - 50) were made from lithium disilicate (IPS E-max CAD), lithium silicate and zirconia based (Vita Suprinity CAD), resin matrix ceramic material (Cerasmart, GC), and dual matrix (Vita Enamic CAD) blocks. After digital impressions (Cerec 3D Bluecam, DentsplySirona), the crowns were designed and manufactured (Cerec 3, DentsplySirona). A dual-curing resin cement was used for cementation (Variolink Esthetic DC, Ivoclar). Then, measurement and recording of crowns and the opposing enamel surfaces with the intraoral scanner were made as well as at the third and sixth month follow-ups. All measurements were superimposed with a software (David-Laserscanner, V3.10.4). Volume loss due to wear was calculated from baseline to follow-up periods with Siemens Unigraphics NX 10 software. Statistical analysis was accomplished by Repeated Measures for ANOVA (SPSS 21) at = .05 significance level. RESULTS: After 6 months, insignificant differences of the glass matrix and resin matrix materials for restoration/enamel wear were observed (P>.05). While there were no significant differences between the glass matrix groups (P>.05), significant differences between the resin matrix group materials (P<.05) were obtained. Although Cerasmart and Enamic were both resin matrix based, they exhibited different wear characteristics. CONCLUSION: Glass matrix materials showed less wear both on their own and opposing enamel surfaces than resin matrix ceramic materials.

Evaluation of Different Thickness, Die Color, and Resin Cement Shade for Veneers of Multilayered CAD/CAM Blocks.

PURPOSE: To investigate the effect of resin cement color on the post-cementation shade of thin laminate veneers milled from multilayered glass ceramic blocks for each layer. MATERIALS AND METHODS: Thin slices (N = 180) with two thicknesses (A: 8 × 8×0.55 mm and B: 8×8×0.8 mm; n = 90/group) were obtained from multilayered glass ceramic blocks using a diamond saw. Resin die specimens were prepared (8 × 8 × 4 mm) (n = 180) and divided into two resin cement colors (D: -3. L: +3) and one control group (C: translucent). Each slice was luted to the composite specimens using a dual-curing resin cement under a constant load of 250 g and light-polymerized for 120 seconds. Specimens were placed on a white background and CIELab values for each layer of the blank slices (incisal [In], body [Bo], and cervical [Ce]) were recorded using a dental contact spectrophotometer. The values were calculated as ΔE, and the data were statistically analyzed (one-way ANOVA, Shapiro-Wilk). RESULTS: Mean ΔE values for A and B were significant (p < 0.05) for In (A: 6.2 ± 1.1; B: 6.6 ± 1.2), Bo (A: 5.1 ± 2.6; B: 3.9 ± 1), and Ce (A: 5.3 ± 2.7; B: 3.8 ± 1.2). Mean ΔE values for In for D and L for A and B groups were significantly higher (6.3 ± 1.2; 6.6 ± 1.2) than Bo and Ce for D (4.4 ± 2.4; 4.6 ± 2.6) and L (4.6 ± 1.4; 4.5 ± 1.7) groups (p < 0.05), respectively. Mean differences between Bo and Ce for A and B groups were insignificant (p ≥ 0.05), while for In the differences were significant. Mean differences between Bo and Ce for A (5.1 ± 2.6; 5.3 ± 2.7) and for B (3.9 ± 1; 3.5 ± 1.2) groups were insignificant (p ≥ 0.05), while for In the differences were significant (6.2 ± 1.1 for A and 6.6 ± 1.2 for B). CONCLUSION: The color changes for body and cervical regions of multilayered ceramic veneers were not affected by resin color or ceramic thickness, but the incisal area was affected. The translucency of each layer in ceramic veneer fabricated with multilayered blanks should be considered for clinical situations.

Comparison of cyclic fatigue resistance of original and counterfeit rotary instruments.

INTRODUCTION: In recent years, with the advances in counterfeiting methods, counterfeit products have reached the dental market. The purpose of this study was to compare the cyclic fatigue resistance of original and counterfeit rotary root canal instruments. MATERIALS AND METHODS: The cyclic fatigue of original and counterfeit ProTaper F2 endodontic instruments was tested (n = 20) in 3 mm radius steel canals with a 60° angle of curvature. The number of cycles to fracture (NCF) was calculated, and the data were subjected to the Student's t-test (α = 0.05). RESULTS: The original instruments showed better cyclic fatigue resistance than the counterfeit ones (p < .001). The mean NCF was 483 ± 84 for the original files and 186 ± 86 for the counterfeit files. CONCLUSIONS: The cyclic fatigue resistance of the counterfeit instruments was very low. As a result, clinicians should be careful not to purchase counterfeit products.

Elastic-plastic finite elements analysis of transient and residual stresses in ceramo-metal restorations.

Transient and residual stresses occurring in partially fixed dental prostheses after the firing process can be calculated with elastic or elastic-plastic finite element analyses (FEA). In this study, firstly, the mechanical and thermal properties at various temperatures of the materials used in a porcelain fused metal (PFM) system were obtained by experimental and literature studies. The effects of viscoelastic and viscoplastic behaviours of the dental porcelain at the elevated temperatures were reflected onto its elastic properties. The equivalent heat transfer coefficients were determined experimentally by measuring temperatures and the results were supplied as input to the 3D finite elements analysis. It has been observed that the maximum stresses occur within a short time period after cooling begins and that stresses decrease during the cooling process and remain at a constant value at the end of cooling; these are the thermal residual stresses.