Association of Non-carious Cervical Lesions with Oral Hygiene Aspects and Occlusal Force.

AIM: The purpose of this case-control (CT) study was to investigate the association between the presence of non-carious cervical lesions (NCCLs) with occlusal force and other potential risk factors. MATERIALS AND METHODS: Thirty-nine participants with NCCLs [cases (CS)] and 39 with no NCCLs [control (CT)] attending the dental clinic of the Faculdades Integradas São Pedro (FAESA), located in Brazil, were enrolled in this study. Information was collected through anamnesis, clinical examination, and a questionnaire addressing aspects related to tooth brushing, dentifrice, and mouthwash use. In clinical examination, patients were submitted to four measurements of occlusal force in the maxillary first premolars and maxillary first molars, using a strain gauge sensor of medium intensity, the Flexiforce (Tekscan, South Boston, Massachusetts, United States of America). The sensor was calibrated for the unit of measurement in Newtons (N). Data were analyzed using a student's t-test and multiple logistic regression, e with a significance level of 5%. RESULTS: There was no statistically significant difference between the case and CT groups regarding the bite force in the four measured regions. Logistic regression identified sex as a factor significantly associated with NCCLs (p = 0.020). The odds ratio showed the female sex had more chance (OR = 6.082; CI = 1.332-27.765) of having NCCLs. CONCLUSION: It is concluded that females presented a higher risk factor for NCCLs than men. In contrast, there was no association of occlusal force, as well as aspects related to brushing and deleterious habits. CLINICAL SIGNIFICANCE: Females have a higher risk factor for non-carious lesions than men.

Biomechanical Behavior Evaluation of a Mandibular Full-Arch Implant-Supported Prosthesis on ZrO2 and TiO2 Monotype Dental Implants / Evaluación del Comportamiento Biomecánico de una Prótesis Implante Soportada de Arcada Completa Mandibular sobre Implantes Dentales Monotipos de ZrO 2 y TiO

This in silico study aimed to evaluate the biomechanical behavior of a full-arch implant-supported prosthesis on titanium and zirconia monotype implants. A 3D mandible containing 1.0 mm thick cortical and cancellous bone was modeled. Four dental implants (3.3 x 10 mm) were inserted into the jaw model in each model. The implants consisted of Titanium (Ti-S group) and Zirconia Monotype/one-piece (Zr-S group). Fixed full-arch implant-supported prostheses were cemented onto the implant. The models were exported to the analysis software and divided into meshes composed of nodes and tetrahedral elements. All materials were considered isotropic, elastic, and homogeneous. Therefore, all contacts were considered bonded, the mandible model was fixed in all directions, applying a static structural axial load of 300 N on the bottom of the fossa of the left mola r teeth. Microstrain and von-Mises stress (MPa) were adopted as failure criteria. Comparable stress and strain values were shown in the peri-implant bone for both groups. However, the Ti-S group presented a lower stress value (1,155.8 MPa) than the Zr-S group (1,334.2 MPa). Regarding bone tissues, the Ti-S group presented 612 µε and the Zr-S group presented 254 µε. The highest strain peak was observed in bone tissues around the implant closer to the load for both groups. Evaluating monotype zirconia and titanium implants, it is suggested that the greater the rigidity of the implant, the greater the concentration of internal stre sses and the less dissipation to the surrounding tissues. Therefore, monotype ceramic implants composed of yttrium-stabilized tetragonal polycrystalline zirconia may be a viable alternative to titanium implants for full-arch prostheses.

El objetivo de este estudio in silico fue evaluar el comportamiento biomecánico de una prótesis implanto soportada de arcada completa sobre implantes monotipo de titanio y zirconia. Se modeló una mandíbula en 3D que contenía tejido óseo cortical y esponjoso de 1,0 mm de espesor. En cada modelo, se insertaron cuatro implantes dentales (3,3 x 10 mm) en el modelo de mandíbula. Los implantes consistieron en Monotipo de Titanio y Zirconia. Sobre el implante se cementaron prótesis implanto soportadas de arcada completa fija. Los modelos se exportaron al software de análisis y se dividieron en mallas compuestas por nodos y elementos tetraédricos. Todos los materiales se consideraron isotrópicos, elásticos y homogéneos. Por lo tanto, todos los contactos se consideraron cementados, el modelo mandibular se fijó en todas las direcciones, aplicando una carga vertical estructural estática de 300 N en el fondo de la fosa de los dientes molares izquierdos. Se seleccionaron la microesfuerzo y la tensión de Von-Mises (MPa) como criterios de falla. Se mostraron valores de tensión y deformación comparables en el hueso periimplantario para ambos grupos. Sin embargo, el grupo Ti-S presentó un valor de estrés menor (1.155,8 MPa) que el grupo Zr-S (1.334,2 MPa). En cuanto a los tejidos óseos, el grupo Ti-S presentó 612 µε y el grupo Zr-S presentó 254 µε. La mayor concentración de deformación en el tejido óseo se observó en los tejidos alrededor del implante más cerca de la carga para ambos grupos. Al evaluar los implantes monotípicos de zirconia y titanio, se sugiere que cuanto mayor sea la rigidez del implante, mayor será la concentración de tensiones internas y menor la disipación a los tejidos circundantes. Por lo tanto, los implantes cerámicos monotipo compuestos de zirconia policristalina tetragonal estabilizada con itrio pueden ser una alternativa viable a los implantes de titanio para prótesis de arcada completa.

Knowledge, Attitudes, and Practices on New Treatment Modalities for Temporomandibular Dysfunctions and Orofacial Pain / Conocimientos, Actitudes y Prácticas sobre Nuevas Nodalidades de Tratamiento de las Disfunciones Tempomanibulares y el Dolor Orofacial

The present study proposed to describe, through a literature review, the use of new therapeutic management which allows for offering a better quality of life to individuals affected by these pathologies. A bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 1987 to 2023 were collected. In the first stage, the list of retrieved articles was examined by reading the titles and abstracts. In the second stage, the studies were selected by reading the full contents. Two authors (JDMM and DAQ) performed stages 1 and 2. Experimental, clinical, case-control, randomized controlled, and laboratory cohort studies, case reports, systematic reviews, and literature reviews, which were developed in living individuals, were included. Therefore, articles that did not deal with the subject in question, letters to the editor, opinion articles, duplicated literature in databases, and literature that did not address the variables under study, we re excluded. Contemporary dentistry uses alternative treatments capable of improving the patient's condition since a cure is not always possible. Therefore, the possibility of improving the quality of life becomes an important point to be reached. Evidence-based healthcare has made great advances in recent decades, especially in the areas of orofacial pain, TMD, and occlusion, especially related to orthodontic, prosthetic, and restorative care.

En el presente estudio se propuso describir, a través de una revisión bibliográfica, el uso de nuevos manejos terapéuticos que permitan brindar una mejor calidad de vida a los individuos afectados por estas patologías. Se realizó una búsqueda bibliográfica en las principales bases de datos de salud PUBMED (www.pubmed.gov) y Scholar Google (www.scholar.google.com.br), en las que se recopilaron estudios publicados entre 1987 y 2023. En la primera etapa, se examinó la lista de artículos recuperados mediante la lectura de los títulos y resúmenes. En la segunda etapa, los estudios fueron seleccionados mediante la lectura del contenido completo. Dos autores (JDMM y DAQ) realizaron las etapas 1 y 2. Se incluyeron estudios de cohortes experimentales, clínicos, de casos y controles, controlados aleatorios y de laboratorio, informes de casos, revisiones sistemáticas y revisiones de la literatura, que se desarrollaron en individuos vivos. Por lo tanto, se excluyeron artículos que no trataran el tema en cuestión, cartas al editor, artículos de opinión, literatura duplicada en bases de datos y literatura que no abordara las variables en estudio. La odontología contemporánea utiliza tratamientos alternativos capaces de mejorar el estado del paciente, ya que no siempre es posible la curación. Por lo tanto, la posibilidad de mejorar la calidad de vida se convierte en un objetivo importante. La atención médica basada en la evidencia ha logrado grandes avances en las últimas décadas, especialmente en las áreas de dolor orofacial, TMD y oclusión, especialmente en relación con la atención de ortodoncia, prótesis y restauración.

Effect of staining layer on roughness after progressive wear of monolithic ceramics.

PURPOSE: The aim of this study was to evaluate staining layer behavior applied to high-translucency zirconia (YZHT), feldspathic ceramics (FD), and zirconia-reinforced lithium silicate (ZLS) surfaces against different antagonists. METHODS AND MATERIALS: Monolithic ceramic discs (n = 120) (ø 12 mm; thickness, 1.2 mm; ISO 6872) were obtained, 30 from YZHT and FD, and 60 from ZLS CAD/CAM blocks (staining layer applied before or after the crystallization procedure). The specimens were divided into 12 subgroups (n = 10) according to the antagonists: steatite, polymer-infiltrated ceramic, or zirconia. Mechanical cycling (1.5 × 104 cycles; 15 N; horizontal displacement, 6 mm; 1.7 Hz) and flexural strength tests (1 mm/min-1000 kg cell) were performed. The differences between final and initial roughnesses (Ra, Rz, and Rsm), the mass loss, and the flexural strength data were individually analyzed by two-way ANOVA and Tukey's test (α = 0.05). RESULTS: The roughnesses of all ceramics did not present a statistically significant difference before wear simulation: Ra (p = 0.3348), Rz (p = 0.5590), and Rsm (p = 0.5330). After the wear simulation, the Ra parameter was not affected by an interaction between ceramic and antagonist (p = 0.595). The Rz and Rsm parameters were affected only by the antagonist pistons (both, p = 0.000). The ceramics used in this study showed statistically significant differences in mass loss after the wear test (p < 0.0001). The additional firing (2 steps) of the ZLS2 led to a higher lost mass quantity. CONCLUSION: All ceramics presented similar initial roughnesses and similar roughnesses after the wear simulation. The zirconia antagonist showed better performance against ceramics with high crystalline content. CLINICAL SIGNIFICANCE: It is clear that restorative materials must be carefully selected by dental practitioners according to indications, properties, and antagonists. The steatite antagonist, that is, an enamel analog, showed better performance against vitreous ceramics, while the zirconia antagonist showed better performance against ceramics with high crystalline content. Wear affects the surface roughnesses of the ceramics. Additional firing for the staining of the zirconia-reinforced lithium silicate ceramic led to a greater loss of mass.

Influence of the Peek Abutments on Mechanical Behavior of the Internal Connections Single Implant.

The present study aimed to evaluate the biomechanical behavior of PEEK abutments with different heights on single titanium implants. To investigate the implant surface, different tests (scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction) were adopted. Herein, 20 implants received the 4.5 × 4.0 mm PEEK short abutment (SA) and 20 received the 4.5 × 5.5 mm PEEK long abutment (LA). The abutments were installed using dual-cure resin cement. To determine the fatigue test, two specimens from each group were submitted to the single load fracture test. For this, the samples were submitted to a compressive load of (0.5 mm/min; 30°) in a universal testing machine. For the fatigue test, the samples received 2,000,000 cycles (2 Hz; 30°). The number of cycles and the load test was analyzed by the reliability software SPSS statistics using Kaplan-Meier and Mantel-Cox tests (log-rank) (p < 0.05). The maximum load showed no statistically significant differences (p = 0.189) for the SA group (64.1 kgf) and the LA group (56.5 kgf). The study groups were statistically different regarding the number of cycles (p = 0.022) and fracture strength (p = 0.001). PEEK abutments can be indicated with caution for implant-supported rehabilitation and may be suitable as temporary rehabilitation.

Influence of Abutment Design on Biomechanical Behavior to Support a Screw-Retained 3-Unit Fixed Partial Denture.

This study aimed to evaluate the biomechanical behavior of Morse taper implants using different abutments (CMN abutment [(CMN Group] and miniconical abutments [MC Group]), indicated to support a screw-retained 3-unit fixed partial denture. For the in vitro test, polyurethane blocks were fabricated for both groups (n = 10) and received three implants in the "offset" configuration and their respective abutments (CMN or MC) with a 3-unit fixed partial denture. Four strain gauges were bonded to the surface of each block. For the finite element analysis, 3D models of both groups were created and exported to the analysis software to perform static structural analysis. All structures were considered homogeneous, isotropic, and elastic. The contacts were considered non-linear with a friction coefficient of 0.3 between metallic structures and considered bonded between the implant and substrate. An axial load of 300 N was applied in three points (A, B, and C) for both methods. The microstrain and the maximum principal stress were considered as analysis criteria. The obtained data were submitted to the Mann-Whitney, Kruskal-Wallis, and Dunn's multiple comparison test (α = 5%). The results obtained by strain gauge showed no statistical difference (p = 0.879) between the CMN (645.3 ± 309.2 µÎµ) and MC (639.3 ± 278.8 µÎµ) and allowed the validation of computational models with a difference of 6.3% and 6.4% for the microstrains in the CMN and MC groups, respectively. Similarly, the results presented by the computational models showed no statistical difference (p = 0.932) for the CMN (605.1 ± 358.6 µÎµ) and MC (598.7 ± 357.9 µÎµ) groups. The study concluded that under favorable conditions the use of CMN or MP abutments to support a fixed partial denture can be indicated.

Implant-Abutment Misfit after Cyclic Loading: An In Vitro Experimental Study.

This study aimed to evaluate the influence of thermomechanical cycling (TMC) and type of abutment on the misfit and compressive strength of the implant−abutment interface. Forty 3.75-mm external hexagon implants with 25° angled abutments were divided into four groups (N = 10). Group A: overcast plus TMC; Group B: overcast without TMC; Group C: completely cast plus TMC; Group D: completely cast without TMC. Abutments were fixed to the implants with 32-Ncm torque, and groups A and C specimens were cyclically loaded at 80 N with 2 Hz for 1 million cycles. The misfit on the implant−abutment interface was evaluated by optical microscope (100×) and the compressive strength test was performed in a universal test machine. For statistical analysis, a two-way ANOVA and post hoc Tukey test were used. There was no difference in misfit presented by all the abutments in the absence of TMC (p > 0.05). When TMC was performed, the completely cast abutments showed greater misfit than overcast ones (p = 0.001). Regarding compressive strength, irrespective of TMC performed, the overcast abutments showed higher compressive strength values than completely cast abutments (p = 0.003). Moreover, disregarding the type of abutment used, the absence of TMC provided higher compressive strength values (p < 0.001). It was concluded that thermomechanical cyclic loading aggravated the misfit, especially in completely cast abutments, regardless of material or fabrication technique, and reduced the compressive strength of the two types of abutments tested.

Bioengineering Tools Applied to Dentistry: Validation Methods for In Vitro and In Silico Analysis.

This study aimed to evaluate the use of bioengineering tools, finite element analysis, strain gauge analysis, photoelastic analysis, and digital image correlation, in computational studies with greater validity and reproducibility. A bibliographic search was performed in the main health databases PUBMED and Scholar Google, in which different studies, among them, laboratory studies, case reports, systematic reviews, and literature reviews, which were developed in living individuals, were included. Therefore, articles that did not deal with the use of finite element analysis, strain gauge analysis, photoelastic analysis, and digital image correlation were excluded, as well as their use in computational studies with greater validity and reproducibility. According to the methodological analysis, it is observed that the average publication of articles in the Pubmed database was 2.03 and with a standard deviation of 1.89. While in Google Scholar, the average was 0.78 and the standard deviation was 0.90. Thus, it is possible to verify that there was a significant variation in the number of articles in the two databases. Modern dentistry finds in finite element analysis, strain gauge, photoelastic and digital image correlation a way to analyze the biomechanical behavior in dental materials to obtain results that assist to obtain rehabilitations with favorable prognosis and patient satisfaction.

The effect of repeated surface treatment of zirconia on its bond strength to resin cement.

PURPOSE: The aim of this study is to evaluate the influence of repeated surface treatments on wettability and surface roughness for zirconia surface and bond strength of zirconia-based ceramics to resin cement. MATERIALS AND METHODS: Seventy blocks (10 × 10 × 3 mm) of zirconia-based ceramics were fabricated and divided into two groups according to the surface treatments: (A) 110 µm Al2O3 airborne-particle abrasion and (R) 110 µm silica modified Al2O3 airborne-particle abrasion. At stage 2, each group was subdivided into 5 groups according to the surface retreatments: (a) 110 µm Al2O3 airborne-particle abrasion, (r) 110 µm silica modified Al2O3 airborne-particle abrasion, (D) diamond bur, (Da) diamond bur + 110 µm Al2O3 airborne-particle abrasion, and (Dr) diamond bur + 110 µm silica modified Al2O3 airborne-particle abrasion. Cylinders of self-adhesive resin cement were cemented onto each treated ceramic surface and subjected to micro-shear bond strength test. Additional specimens were prepared for roughness and wettability analyses. The data were subjected to t-test and One-way ANOVA followed by Tukey's post hoc test (α=.05). RESULTS: At stage 1, group R presented higher bond strength values than group A (P=.000). There was a statistically significant increase of bond strength at stage 2 for group A (P=.003). The diamond bur influenced the surface roughness, increasing the values (P=.023). Group R provided better wettability. Regardless of the applied surface treatment, most of failures were adhesive. CONCLUSION: The combination of application and reapplication of Rocatec Plus showed the best results of bond strength. Surface retreatment and recementation might be an indicated clinical strategy.

The behavior of a zirconia or metal abutment on the implant-abutment interface during cyclic loading.

STATEMENT OF PROBLEM: The effect of different abutment materials on the misfit and stability of the implant-abutment assembly under cyclic loading is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the initial misfit, final misfit, and wear of external hexagon zirconia and metal implant abutments upon cyclic loading. MATERIAL AND METHODS: Forty 4.1-mm regular platform external connection implants were divided into 4 groups with 10 specimens in each group. The prosthetic abutments tested included Completely cast group (CC) (antirotational, castable burnout, custom abutment completely cast in nickel-chromium-titanium), Overcast group (OC) (Co-Cr premachined, antirotational, custom burnout abutment cast in nickel-chromium-titanium), Zirkonzahn group (Z) (antirotational castable, custom Y-TZP abutment produced; Zirkonzahn Prettau), and Neodent group (N) (antirotational castable, custom Y-TZP abutment; Neoshape). Abutments were fixed to the implants with 20-Ncm torque, and all specimens were cyclically loaded at 300 N with 9 Hz for 1 million cycles. The misfit on the implant-abutment interface was evaluated before and after cyclic loading by using an optical linear measuring microscope. Then, the wear of the external hexagon was analyzed by scanning electron microscopy (SEM) at a magnification of ×120. For a statistical analysis, a 1-way ANOVA was used for wear values. The data for the gaps were analyzed with a 2-way ANOVA. Any significant differences were resolved by using the Tukey HSD test (α=.05). RESULTS: The CC (37 ±8 µm) and OC (35 ±5 µm) groups showed significantly larger initial misfit than the Z (4 ±5 µm) and the N (2 ±4 µm) groups (P<.05). After the mechanical cyclic loading, a statistically significant difference was found between the CC group (58 ±9 µm) and the other 3 groups (P<.05). The OC group (41 ±4 µm) showed significantly larger final misfit than the Z (19 ±7 µm) and the N groups (20 ±4 µm) (P<.05). Despite significantly increased misfit in all groups (P<.05), the OC group showed significantly less increased gap (6 µm) than the Z (15 µm) and the N (18 µm) groups, while CC showed the most increase in misfit (21 µm). Conversely, N (1313 ±315 µm2) and Z (735 ±126 µm2) groups showed significantly higher wear rate on the hexagon of external implants. The CC (231 ±182 µm2) and OC (201 ±125 µm2) groups were not statistically different. CONCLUSIONS: Different materials and fabrication techniques resulted in different levels of misfit at the implant-abutment interface. The mechanical cyclic loading aggravated the misfit, regardless of material or fabrication technique. In addition, the difference in the hardness of the abutment materials may lead to different levels of wear on the external hexagon. Zirconia abutments had increased wear and misfit. Premachined, antirotational, castable custom dental implant abutments had the least amount of change in misfit, which may indicate long-term stability at the implant-abutment interface.

Influence of disinfection with peracetic acid and hypochlorite in dimensional alterations of casts obtained from addition silicone and polyether impressions.

Dental impressions disinfection is important to reduce the risk of cross contamination but this process may produce dimensional distortions. Peracetic acid is a disinfectant agent with several favorable characteristics yet underutilized in Dentistry. The aim of this paper is to compare the dimensional stability of casts obtained from addition silicone and polyether impressions that were immersed for 10 minutes in a solution of 0.2% peracetic acid or 1% sodium hypochlorite. Sixty samples in type IV gypsum were produced after a master cast that simulated a full crown preparation of a maxillary premolar. Samples were divided in 6 groups (n = 10) according to the impression material and disinfection agent: Group AC--addition silicone control (without disinfectant); Group APA--addition silicone + 0.2% peracetic acid; Group AH--addition silicone + 1% sodium hypochlorite; Group PC--polyether control (without disinfectant); Group PPA--polyether + 0.2% peracetic acid; Group PH--polyether + 1% sodium hypochlorite. Cast height, base and top diameter were measured and a mean value was obtained for each sample and group all data was statistically analyzed (ANOVA, p < 0.05). There was not a significant statistical difference between addition silicone and polyether impressions regardless of the disinfectant materials. It can be concluded that disinfection with the proposed agents did not produce significant alterations of the impressions and the peracetic acid could be considered a reliable material to disinfect dental molds.

Influence of the casting material on the dimensional accuracy of dental dies

The purpose of this study was to evaluate the dimensional accuracy of different materials used in the confection of dies. Two stainless steel standard models were confected. One of the models, which was 2 mm larger than the other model, was used to provide a uniform relief for the two-step putty-wash impression technique. Thirty impressions were obtained using a polyvinyl siloxane impression material and randomly divided into three groups (n = 10) according to the type of casting material: type IV dental stone, commercially available epoxy resin (Tri-Epoxy), and industrial epoxy resin (Sikadur). After the setting/polymerization of the casting material, the dimensional stability was measured in terms of the height, diameter of the base and diameter of the top from the obtained dies and from the standard metal model using a profile projector. Results were analyzed by ANOVA and Dunnet test (α = 0.05). In the height values, no significant difference was observed between the groups, except for Sikadur casts, which showed lower mean values. The Tri-Epoxi group showed statistically lower mean base diameter values, compared with the other groups, and both epoxy resin groups showed statistically lower mean top diameter values, compared with that for the type IV dental stone group. We concluded that type IV gypsum and the commercially available epoxy resin showed similar behavior in most areas. The industrial epoxy resin did not show the same characteristics, although the diameter of the base obtained with it was similar to that obtained with type IV dental stone.