Journal of Clinical and Experimental Dentistry最新文献

The emergence profile in implant restoration has an important contribution to the final esthetic result. Moreover, a properly shaped emergence profile enables well-performed dental hygiene and protects the implant-restoration complex from peri-implant infections. This report describes a clinical case that combines digital workflow and designing with a custom implant healing abutment system (Cervico). This system is utilized to customize the provisional restoration's emergence profile with the conventional processing along with the digitally designed and milled provisional restoration to deliver an interim prosthesis after implant placement. Key words:Cervico, Customized emergence profile, Digital Dentistry, Implant surgical guide, Implant provisionals.

Background: Considering the variability of finishing protocols for composite resins, the literature does not offer a consensus about the influence of these approaches to obtain a final polishing and whether the physical properties of these composite resins change at different analysis times. Therefore, the study analyzed the microhardness, roughness, color stability, and gloss of a nanocomposite resin with different finishing, aging with coffee, and repolishing protocols.

Material and methods: Nanocomposite resin samples were divided into three finishing protocol groups: Diamond burs (F and FF), multi-fluted tungsten carbide burs (18 and 30 flutes), and coarse and medium abrasive discs (Soflex-3M). All protocols used spiral rubber tips (F and FF) for polishing. Knoop microhardness (KHN), roughness (Ra), color changes (ΔE00 and YI), and gloss (GU) were analyzed. Scanning electron microscopy provided images of resins and finishing and polishing instruments.

Results: Resin KHN (p<0.001) decreased, and Ra (p<0.001), ΔE00 (p<0.001), and YI (p<0.001) increased after aging with coffee, regardless of finishing protocol. Abrasive discs showed lower color changes, YI, and Ra and higher GU. Repolishing restored KHN and Ra but not ΔE00 (p>0.05) and YI (p>0.05).

Conclusions: Abrasive disc finishing reduced roughness and yellowness and increased nanocomposite resin gloss after aging with coffee. Key words:Color, Composite resins, Dental materials, Staining, Surface properties.

Background: To evaluate the thermal insulation of protective liners and glass ionomer cement during light-curing procedures.

Material and methods: Human third molars underwent Class I preparations with dimensions 5 mm long × 4 mm wide × 4 mm deep in a standardized manner ensured a consistent ±0.5 mm dentin thickness at the pulpal floor. The teeth were attached to a customized oral cavity chamber simulator with a circulating bath at a standardized temperature of 34.2 ± 1oC. The temperature variations at the pulpal floor were captured in real-time by video using an infrared thermal camera (FLIR ONE Pro, FLIR Systems). The materials evaluated were: Dycal (Dentsply), TheraCal LC (Bisco), Activa (Pulpdent), and Fuji II LC (GC). All light-activation procedures were performed with the same light-curing unit (Valo Grand, Ultradent) in standard mode, 1000 mW/cm2, and time of exposure following manufacturer instructions. A power analysis was conducted to determine the sample size considering a minimal power of 0.8, with α=0.05. Statistical analyses were performed using ANOVA and Tukey's test for multiple comparisons.

Results: The temperature at the pulpal floor increased above the 5.5 ºC safety threshold difference for clinical scenarios tested. None of the materials provided proper thermal insulation for light-curing procedures (p = 0.25). The higher the number of light-cured steps, the longer the pulp remained above the 5.5 ºC temperature threshold.

Conclusions: The materials tested provided improper thermal insulation (Δ > 5.5 ºC). Thus, prolonged or multiple light-curing exposures can be harmful to the pulp tissues. Therefore, for indirect pulpal capping procedures, self-cured materials or a reduced number of steps requiring light curing must be adopted to reduce the amount of time the pulp remains above the 5.5 ºC safety temperature threshold. Key words:Dental Pulp Capping, Calcium hydroxide, Bioactive, Thermal Damage.

Background: To evaluate the effect of different finishing and polishing systems on the surface roughness and color changes of bis-acryl (Protemp 4 - 3M ESPE- St. Paul, USA; Structur 3 - Voco, Cuxhaven, Germany) and chemically activated acrylic materials (Duralay - Reliance, SP, Brazil).

Material and methods: Specimens (10 x 2 mm) thick were prepared for each material. The specimens were subjected to polishing and finishing procedures with aluminum oxide discs (Diamond Master - FGM, Joinville, Santa Catarina, Brazil) and spiral rubber disks (Sof-Lex - 3M ESPE, Germany). The control did not receive any polishing and finishing procedures. Surface roughness and color measurement values were obtained after the finishing and polishing procedures and immediately after 30 days of storage in water, coffee, and red wine. Data for each material were analyzed by One-Way ANOVA (p<0.05).

Results: The polishing with aluminum oxide discs was able to affect the initial surface roughness values of chemically activated acrylic material (p<0.05). After immersion in staining solutions, lower ∆E values were only observed for the bis-acryl composite resins compared to the control group (p<0.05).

Conclusions: The finishing and polishing systems influenced the surface roughness and color stability of the materials tested. The chemically activated acrylic resin showed lower surface roughness and higher color stability than the bis-acryl materials. Key words:Acrylic resin, bis-acryl resin, provisional restoration.

Background: The aim of this study was to compare the fracture strength of two different Ribbond Fiber (Ribbond, Ribbond Inc., Seattle, WA, USA) restoration strategies in 5 mm deep standardized MOD cavities without interaxial dentin.

Material and methods: 34 extracted human molars were randomly divided into two groups and restored as follows: Group 1 restoration with Ribbond Fiber placed at the cavity floor incorporated in Estelite Bulk-Fill Flow Universal composite (Tokuyama Dental Corporation Inc., Tokyo, Japan); Group 2 restoration with RF placed at 3 mm from the occlusal plane over a 2mm layer of Estelite Bulk-Fill Flow. The occlusal plane in both groups was restored with Ceram.x Spectra ST (Dentsply Sirona, Ballantyne Corporate Pl, Charlotte, NC, USA). The restored teeth were subjected to thermal cycling by immersing them for 30 seconds in hot water (55±2°C) followed by 30 seconds in cold water (5±2°C), for 2000 cycles.Their fracture strength was then evaluated using an Instron device. Data were analyzed with Two-sample T Test statistical test to compare fracture strength among groups. Finally, a descriptive analysis of the failure location was performed.

Results: A statistically significant difference was found between groups 1 and 2 (P<0.001) in terms of fracture strength. Group 2 exhibited a higher percentage of recoverable fractures compared to group 1. Group 1 had a mean fracture load of 833N and a SD of 248 while group 2 had a mean fracture load of 1286N and SD of 447.

Conclusions: RF placed at 3 mm depth from the occlusal plane, on a 2 mm layer Estelite Bulk-Fill Flow Universal composite (Tokuyama Dental Corporation Inc., Tokyo, Japan) contributes to improve fracture resistance in vital teeth without interaxial dentin and reduces the risk of non-recoverable fractures compared to when it is placed at a 5 mm depth. Key words:Ribbond fiber, composite restoration, fracture resistance, Instron machine.

Background: This study aims to assess the efficacy of Er; Cr: YSGG laser operating under sub-ablative settings for the remineralization of artificially induced white spot lesions on the enamel of primary teeth, both as a standalone treatment and in conjunction with 1.23% acidulated phosphate fluoride (APF) gel.

Material and methods: Eighty primary posterior teeth were used to induce white spot lesions and were randomly divided into eight groups. The groups consisted of a negative control group (G1), a 0.75W laser irradiation group (G2), a 0.5W laser irradiation group (G3), a 0.25W laser irradiation group (G4), a positive control group with APF gel application (G5), and three groups that received laser irradiation of 0.75W, 0.5W, and 0.25W followed by APF gel application (G6, G7, and G8) respectively. Surface microhardness, SEM, and X-RD were used to evaluate the remineralization effect.

Results: There was a notable enhancement in surface microhardness post-treatment with the laser, APF gel, and their combination compared to the negative control group. The most pronounced increase in surface microhardness was observed in the combination treatment groups (G6, G7, and G8). SEM analysis showed increased surface roughness in groups treated with 0.75W and 0.5W laser power. X-RD assessments indicated an augmentation in crystal intensity within groups G6 and G8.

Conclusions: The combined application of Er; Cr: YSGG laser under sub-ablative parameters and APF gel demonstrated a superior potential for remineralizing primary teeth enamel affected by white spot lesions. Key words:Er;Cr:YSGG laser. Sub-ablative irradiation. Remineralization. White spot lesion. APF gel. SEM. X-RD.

Orofacial dyskinesia (ODk) is an involuntary, repetitive and stereotyped movement disorder of the oro-bucco-lingual muscles, which can be classified as primary (idiopathic) or secondary to medical conditions such as oral peripheral factors, that may act as triggers or aggravators. The present case describes a 70 years female with ODk, non-associated to drug use, without central etiological factors or morbid conditions, but with the presence of a flawed prosthodontic treatment, which complaint from spasms in the masticatory muscles that alters jaw dynamics, and her ability for maintain a relaxed jaw in maximal intercuspal position. After an unsuccessful oral drug treatment, botulinum toxin was injected to the jaw muscles with favorable results. The case illustrated that peripheral factors, such as defective dental prosthetics, may trigger or aggravate orofacial movement disorders, and peripheral strategies such as botulinum toxin may contribute to improve clinical parameters and quality of life. Key words:Botulinum toxin, case report, dyskinesia, movement disorder, orofacial dyskinesia.

Background: Achieving adequate aesthetics with implants in the anterior sector continues to be a challenge. One of the most studied and currently used techniques is the use of autologous connective tissue grafts to improve the peri-implant soft tissues in this area. Our objective is to analyze whether these techniques have a predictable impact on the tissues and aesthetics; and if it is worth performing them.

Material and methods: A bibliographic search was carried out, including different digital portals.

Results: A total of 8 articles were analyzed. This procedure did not have an impact on the hard tissue but did have an impact on gingival recessions and soft tissue thickness. Regarding aesthetics, the results are controversial. It seems that they can slightly improve the PES (Pink Esthetic Score or Pink Index). Also, a negative impact on the texture of the soft tissue has been found.

Conclusions: It is necessary to individualize each case (especially depending on the gingival biotype) since taking a connective tissue graft from the palate entails discomfort for the patient, and this technique is not free of complications. Key words:Dental implants, aesthetics, connective graft.

Background: Actinic cheilitis (AC), an oral potentially malignant oral disorder (OPMD), predominantly affects fair-skinned individuals, particularly males, with a higher prevalence in their sixth and seventh decades. In the Southeast region of Brazil, oral cancer ranks as the fourth most common tumor among males, with squamous cell carcinoma (SCC) constituting 90% to 95% of lip tumor cases, primarily impacting the lower lip. This retrospective study aims to evaluate the malignant transformation rate in previously diagnosed AC patients between 2008 and 2018, utilizing biopsy records.

Material and methods: We retrospectively reviewed medical records of lip lesion patients at the Department of Oral and Maxillofacial Surgery (DOMS) during the stated period, collecting demographic and medical data for analysis.

Results: Among the 224 analyzed AC cases, 67.8% were male, with an average age of 65 years. Approximately 87.6% of patients reported occupational exposure to AC-associated risk factors. Malignant transformations occurred in 27 patients (12.05%).

Conclusions: Our study underscores the possible effect of early intervention and preventive measures in stabilizing AC lesions and averting their progression to malignancy. These findings underscore the significance of prompt AC diagnosis and management to mitigate the risk of malignant transformation. Key words:Actinic cheilitis, oral squamous cell carcinoma, malignant transformation.

Background: Maxillary sinuses may present a wide spectrum of anatomical variations and pathological lesions whose recognition is mandatory for the clinician, especially prior to any surgical intervention in the area, such as in cases of sinus floor elevation. The goal of this study was the evaluation, mapping and prevalence of sinus anatomical variants and pathoses in Cone Beam Computed Tomography (CBCT) scans of dental patients.

Material and methods: 660 CBCT examinations of adult patients involving both sinuses were obtained (between 2017 and 2023) and analyzed. The following anatomic variants and pathologic findings were evaluated: antral septa (AS), posterior superior alveolar artery (PSAA), sinus hypoplasia, sinusitis, odontogenic cysts, retention cysts, antroliths, and various less common lesions (e.g.: benign fibro-osseous dysplastic lesions, neoplasms etc.). Investigation of the association of the findings with patients' age and gender was performed using the Chi-square test (X2), Fisher's exact test, t-test, and ANOVA (P<0.05). Differences in prevalence between findings, based on their location (right and/or left sinus), were investigated using z-test and t-test.

Results: AS were found in 38.6%, and PSAA was identifiable in 90.2% (mean distance from the sinus floor=6.44 mm) of the patients respectively. 3% of patients had hypoplasia, 15.6% sinusitis, 2.7% odontogenic cysts, 16.1% retention cysts, 8.6% antroliths, and 1.7% uncommon lesions (e.g. malignant neoplasms and fibrous dysplasia). A statistically significant association was found between gender and PSAA diameter, PSAA distance from the sinus floor, hypoplasia, sinusitis, and retention cysts, as well as a statistically significant association between age and PSSA diameter and sinusitis.

Conclusions: The prevalence of various anatomical variants and pathologic findings of the maxillary sinus did not differ based on their location. However, some of these findings appear to be related to either gender or age. CBCT is a valuable diagnostic tool to identify various anatomical variants and pathological findings of the maxillary sinus. Key words:Sinus, anatomy, pathology, CBCT.