Selamento dentinário imediato em restauração semidireta: relato de caso / Immediate dentin sealing in semi-direct restoration: case report

O selamento dentinário imediato é um procedimento essencial na Odontologia, que envolve a aplicação de agentes de selamento na interface entre a dentina e o material restaurador imediatamente após a remoção da cárie e do preparo da cavidade dentária. Este processo busca selar os túbulos dentinários expostos, proporcionando proteção à polpa dentária. O presente caso foi realizado em um paciente do sexo masculino, 56 anos que se queixou de desconforto no elemento dentário 17. Após avaliação clínica e radiográfica, foi constatado uma ampla restauração desadaptada na porção mesio - oclusal do referido dente, sendo que o elemento em questão não possui tratamento endodôntico. Após planejamento e assinatura do TCLE, os seguintes passos foram realizados: remoção da lesão cariosa do dente 17, seguido da realização do levantamento marginal mesial e a realização do selamento dentinário imediato. Moldagem com silicone de adição do dente em questão e do antagonista, assim como registro da mordida. Foi confeccionada uma restauração semidireta em resina composta sob o modelo de gesso obtido. A cimentação da restauração foi feita na consulta seguinte, cumprindo os requisitos fundamentais para restaurar forma, função e estética, resultando na melhoria da qualidade de vida do paciente(AU)

Immediate dentin sealing is an essential procedure in dentistry, involving the application of sealing agents at the interface between dentin and the restorative material immediately after caries removal and cavity preparation. This process aims to seal exposed dentinal tubules, providing protection to the dental pulp. The present case involved a 56-year-old male patient who complained of discomfort in tooth number 17. After clinical and radiographic evaluation, a wide, maladapted restoration in the mesio-occlusal portion of the tooth was identified, with no endodontic treatment in the affected element. Following planning and informed consent, the following steps were taken: removal of the carious lesion from tooth number 17, followed by the execution of mesial marginal elevation and immediate dentin sealing. Silicone addition molding of the affected tooth and antagonist, along with bite registration, was performed. A semi-direct restoration in composite resin was fabricated based on the obtained gypsum model. The restoration was cemented in the subsequent appointment, meeting the essential requirements to restore form, function, and aesthetics, resulting in an improvement in the patient's quality of life(AU)

Effects of endodontic root canal irrigants on tooth dentin revealed by infrared spectroscopy: a systematic literature review.

BACKGROUND: Root canal irrigation endodontic solutions have effects on the chemistry of dentin. Infrared spectroscopy is a non-destructive chemical characterization method where the strength of absorption often correlates with mineral or organic composition. OBJECTIVES: To survey effects of commonly used irrigation solutions on the composition of root dentin as detected by widely-available Fourier transform infrared spectroscopy (FTIR) methods. METHODS: Electronic databases were searched for articles published between 1983 to 2023. After risk of bias assessments (OHAT), studies were grouped according to effects per irrigation solution. Inclusion criteria comprised in vitro studies that used extracted human or bovine teeth, treated by irrigation solutions characterized using FTIR spectroscopy and presenting spectral data. Publications that did not share FTIR spectra were excluded. RESULTS: A wide range of concentrations, durations, and methodologies have been tested but only 30 out of 3452 studies met our inclusion criteria. Different FTIR methods were used with the Attenuated Total Reflection (ATR) variant being the most common (21 studies). Investigated solutions included sodium hypochlorite (NaOCl), ethylenediaminetetraacetic-acid (EDTA), 1-hydroxyethylidene-1-1-diphosphonic-acid (HEDP), peracetic-acid (PAA), glycolic-acid (GA), and citric-acid (CA) though most focused on NaOCl and EDTA. All solutions had detectable effects on the FTIR signature of dentin. NaOCl mainly affects the organic signatures, revealing reduced amide/phosphate ratios with increasing concentrations. EDTA mainly effects the inorganic component, increasing with time and concentration, yet glycolic acid has stronger effects than EDTA on dentin. Beyond the type of irrigant and dentin exposure durations, concentration and protocol of application had strong effects. There is a lack of studies comparing similar irrigants under conditions that mimic clinical scenarios analyzing bulk sample because FTIR of powder dentin differs from bulk measurements. SIGNIFICANCE: The ideal root-canal irrigant should combine local disinfection properties with minimal compositional effects on healthy dentin. FTIR methods appear reliable to identify important changes in root dentin chemical composition. Such information can help understand when endodontic irrigation might lead to root degradation or possibly contribute to long term failures such as vertical fractures. Awareness of chemical damage from irrigation procedures may help clinicians select procedures that reduce deleterious effects on the root canal structures.

Brazilian undergraduates' and dentists' knowledge on preventing, diagnosing and managing dentin hypersensitivity: A cross-sectional questionnaire study.

OBJECTIVES: To analyse the knowledge of dental undergraduates and dentists on the prevention, diagnosis and management of dentin hypersensitivity (DH); to compare their knowledge scores; and to understand the related variables using a regression model. METHODS: An original online questionnaire investigated the attitudes, self-reported knowledge ('how much they thought they knew') and real knowledge ('how much they really knew') of 132 students and 338 dentists. Data were analysed descriptively, both knowledge scores were compared using Mann-Whitney and Wilcoxon signed-rank tests and data were subjected to two multiple linear regression analyses considering real knowledge scores as the dependent variable (α < 0.05). RESULTS: The self-reported knowledge on DH was higher than the real knowledge for both students and dentists, but dentists presented the highest scores. Gingival recession and acidic diet were reported as the main predisposing factors for DH by undergraduates and dentists. Students normally managed DH with dietary and hygiene instructions followed by a desensitizing agent application, while dentists managed with occlusal adjustments. The mechanism of glutaraldehyde/HEMA and bioactive fillers on DH is widely unknown by students and dentists. The majority of the questioned individuals cannot differentiate DH from sensitivity of caries or molar-incisor hypomineralization. CONCLUSION: Both students and dentists overestimate their knowledge of DH, revealing deficiencies in prevention, diagnosis and management. Students' knowledge improves towards the end of the Dentistry course, while younger dentists and PhD holders are more knowledgeable. Institutions should implement ongoing DH education for undergraduates and conduct interventions for experienced professionals, especially older ones.

Heparin-Functionalized Bioactive Glass to Harvest Endogenous Growth Factors for Pulp Regeneration.

Pulp and periapical diseases can lead to the cessation of tooth development, resulting in compromised tooth structure and functions. Despite numerous efforts to induce pulp regeneration, effective strategies are still lacking. Growth factors (GFs) hold considerable promise in pulp regeneration due to their diverse cellular regulatory properties. However, the limited half-lives and susceptibility to degradation of exogenous GFs necessitate the administration of supra-physiological doses, leading to undesirable side effects. In this research, a heparin-functionalized bioactive glass (CaO-P2O5-SiO2-Heparin, abbreviated as PSC-Heparin) with strong bioactivity and a stable neutral pH is developed as a promising candidate to addressing challenges in pulp regeneration. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis reveal the successful synthesis of PSC-Heparin. Scanning electron microscopy and X-ray diffraction show the hydroxyapatite formation can be observed on the surface of PSC-Heparin after soaking in simulated body fluid for 12 h. PSC-Heparin is capable of harvesting various endogenous GFs and sustainably releasing them over an extended duration by the enzyme-linked immunosorbent assay. Cytological experiments show that developed PSC-Heparin can facilitate the adhesion, migration, proliferation, and odontogenic differentiation of stem cells from apical papillae. Notably, the histological analysis of subcutaneous implantation in nude mice demonstrates PSC-Heparin is capable of promoting the odontoblast-like layers and pulp-dentin complex formation without the addition of exogenous GFs, which is vital for clinical applications. This work highlights an effective strategy of harvesting endogenous GFs and avoiding the involvement of exogenous GFs to achieve pulp-dentin complex regeneration, which may open a new horizon for regenerative endodontic therapy.

Dentin Collagen versus Er:YAG Laser as Surface Biomodifiers for Intact Root Slices Simulating Delayed Replanted Roots.

Objective: To evaluate effects of dentin collagen versus Er:YAG laser application through enhancing human periodontal ligament fibroblast (PDLF) cells to attach to intact root surfaces imitating delayed replanted roots. Background Data: Accidental traumatic injuries with teeth avulsion are managed by replantation. Root resorption, poor conditioning, and non-viable fibroblasts are factors responsible for failure. Methods: Thirty six human healthy single-rooted premolars were collected. Six teeth were used for PDLF, six teeth used for dentin collagen, whereas the remaining 24 teeth (48 root slices) were used for PDLF cell density and morphology. Each root was soaked in 5.25% NaOCl. Three groups (n = 16 slices/each) were planned as follows: I: Control (untreated); II: dentin collagen application; III: Er:YAG laser irradiation (4 mm distance, 40 mJ/pulse, under coolant). Following incubation, cell density and morphology of PDLF were investigated under SEM. Statistical analysis was performed using analysis of variance with Scheffé's test, and p < 0.05 was considered significant. Results: All groups showed increased cultured PDLF following incubation. Regarding cell density, attached PDLFs were significantly lower in untreated controls (36.5 ± 6.36) (p < 0.00001 i.e., <0.05) in negative empty and/or light cellular areas, compared with dentin collagen (65 ± 6) and laser-irradiated (66.75 ± 5.77) groups that did not show significant differences (p = 0.940 i.e., >0.05) and showed intermediate and/or heavy cellular areas. Regarding cell morphology, controls showed round and/or oval appearance with less lamellipodia, whereas dentin collagen and laser groups showed flat morphology with cytoplasmic processes. Conclusions: Both dentin collagen and Er:YAG laser showed comparable effectiveness as biomodification tools with good biocompatibility for human PDLF cell attachment on intact root slices imitating delayed replantation. Dentin collagen as a natural bioactive material is considered an alternative to Er:YAG laser to enhance the regenerative effects.

Reviving a Smile: A Multidisciplinary Approach to Dentin Dysplasia.

Dentin dysplasia Type 1 (DD1) is an uncommon inherited condition marked by structural irregularities in dentin, leading to notable dental abnormalities. Clinically, patients typically present with generalized slight yellowish discoloration and tooth mobility, while radiographic examination often reveals a reduced pulp chamber with the absence of pulp stones, a hallmark feature of DD1. Treatment involves a multidisciplinary approach including extraction of affected teeth, direct sinus lift procedure bilaterally, implant placement, and subsequent fixed prosthesis placement. In a recent case, after six months, a patient demonstrated improved oral health-related quality of life with stabilized implant-supported prostheses providing functional and esthetic benefits. This emphasizes the importance of early diagnosis and intervention in managing DD1, underscoring the effectiveness of a multidisciplinary approach in enhancing oral function and esthetics. Further research is warranted to deepen our understanding of the genetic basis of this condition and develop targeted therapies.

Effects of a relined fiberglass post with conventional and self-adhesive resin cement.

Objectives: This study was conducted to evaluate the mechanical properties of relined and non-relined fiberglass posts when cemented to root canal dentin using a conventional dual-cure resin cement or a self-adhesive resin cement. Materials and Methods: Two types of resin cements were utilized: conventional and self-adhesive. Additionally, 2 cementation protocols were employed, involving relined and non-relined fiberglass posts. In total, 72 bovine incisors were cemented and subjected to push-out bond strength testing (n = 10) followed by failure mode analysis. The cross-sectional microhardness (n = 5) was assessed along the root canal, and interface analyses (n = 3) were conducted using scanning electron microscopy (SEM). Data from the push-out bond strength and cross-sectional microhardness tests were analyzed via 3-way analysis of variance and the Bonferroni post-hoc test (α = 0.05). Results: For non-relined fiberglass posts, conventional resin cement exhibited higher push-out bond strength than self-adhesive cement. Relined fiberglass posts yielded comparable results between the resin cements. Type II failure was the most common failure mode for both resin cements, regardless of cementation protocol. The use of relined fiberglass posts improved the cross-sectional microhardness values for both cements. SEM images revealed voids and bubbles in the incisors with non-relined fiberglass posts. Conclusions: Mechanical properties were impacted by the cementation protocol. Relined fiberglass posts presented the highest push-out bond strength and cross-sectional microhardness values, regardless of the resin cement used (conventional dual-cure or self-adhesive). Conversely, for non-relined fiberglass posts, the conventional dual-cure resin cement yielded superior results to the self-adhesive resin cement.

Single-session associative protocol for dentin hypersensitivity management: a 1-year randomized, blinded clinical study.

Objectives: This study aimed to establish a single-session associative protocol for non-restorative management of dentin hypersensitivity (DH). Materials and Methods: Twenty-four individuals with DH and a minimum sensitivity level of 4 on the visual analog scale (VAS) were selected. The study was conducted in a split-mouth design, with each participant (n = 20) having at least 1 affected tooth in all quadrants. The management protocols consisted of control group: universal adhesive, Neural Desensitizing Protocol group: 5% potassium nitrate, Mixed Desensitizing Protocol (PAM) group: 5% sodium fluoride and 5% potassium nitrate, Remineralizing Desensitizing Protocol (PDR) group: surface-partially reacted glass technology photopolymerizable varnish. Evaluations were performed immediately after application, at 1 week, 1 month, 2 months, and 12 months using the VAS sensitivity test. Results: The scores were subjected to statistical analysis using the Friedman test (p < 0.05), Durbin-Conover test (p < 0.05), and Wilcoxon test (p < 0.05). At the 12-month evaluation, all groups showed statistically significant differences compared to the initial assessment. For the evaluation after 12 months, there was a statistically significant difference between the PAM group, the control group, and the PDR group. Conclusions: It can be concluded that all groups were effective in controlling DH, but there were significant results in the control group and PDR group. The clinical relevance of this study is to demonstrate that the application of single-session desensitizing protocols can be effective in controlling DH for up to 12 months. Trial Registration: Brazilian Clinical Trials Registry Identifier: RBR-4r63d7s.

Dentin-derived alveolar bone graft for alveolar augmentation: A systematic review.

Introduction: Application of alveolar bone graft (ABG) in alveolar augmentation is done to prevent excessive bone resorption due to tooth extraction, missing teeth, or other diseases/conditions affecting the alveolar bone. The use of autogenous dentin-derived ABG has been considered as the composition of dentin appears to be nearly analogous to that of bone. Objective: This systematic review aims to assess the efficacy of dentin-derived ABG for alveolar augmentation of post-extraction sockets or other alveolar bone defects by evaluating volume gain and histomorphometric data. Material and methods: A search of systematic literature was conducted in Pubmed, Scopus, Web of Science, and Embase from database inception to October 2023. The review included both randomized controlled trials (RCT), pilot studies, clinical trials, and retrospective studies reporting on dentin-derived ABG use for alveolar augmentation. Results: Overall, 298 articles were obtained from the initial search. From these articles, 21 articles met the inclusion criteria and were included for descriptive analysis. All of the studies indicated low risk of bias. Studies of dentin-derived ABG, which used bone-derived grafts as the control group, have shown significantly higher percentages of new bone formation, gain in vertical and horizontal dimensions, and less reduction in dimensions. Conclusions: Dentin-derived ABG was effective in volume maintenance, indicating promising results via histomorphometric and radiographic analysis.

CYP4A22 Loss-of-Function Causes A New Type of Vitamin D-dependent Rickets (VDDR1C).

Vitamin D dependent rickets (VDDR) is a group of genetic disorders characterized by early-onset rickets due to deficiency of active vitamin D or a failure to respond to activated vitamin D. VDDR is divided into several subtypes according to the corresponding causative genes. Here we described a new type of autosomal dominant VDDR in a Chinese pedigree. The proband and his mother had severe bone malformations, dentin abnormalities, and lower serum 25 hydroxyvitamin D3 (25 (OH)D3) and phosphate levels. The proband slightly responded to high dose of vitamin D3 instead of daily low dose of vitamin D3. Whole exome sequencing, bioinformatic analysis, PCR and Sanger sequencing identified a nonsense mutation in CYP4A22 (c.900delG). The overexpressed wild type CYP4A22 mainly localized in endoplasmic reticulum and Golgi apparatus, and synthesized 25 (OH)D3 in HepG2 cells. The overexpressed CYP4A22 mutant increased the expression of CYP2R1 and produced little 25 (OH)D3 with vitamin D3 supplementation, which was reduced by CYP2R1 siRNA treatment. We concluded that CYP4A22 functions as a new kind of 25-hydroxylases for vitamin D3. Loss-of-function mutations in CYP4A22 lead to a new type of VDDR type 1 (VDDR1C). CYP2R1 and CYP4A22 may have some genetic compensation responding to nonsense-mediated mRNA decay effect of each other.

A nonsense mutation in CYP4A22 was found in a Chinese pedigree with vitamin D dependent rickets and low serum phosphate. CYP4A22 localizes in endoplasmic reticulum and Golgi apparatus, and processes 25-hydroxylase activity in liver cells. CYP4A22 loss of function reduce the synthesis of 25(OH)D3 and cause genetic compensation of CYP2R1.

Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study.

AIM: The aim of the study is to determine the difference in the shear bond strengths to dentin among dental composite (Filtek Z350®, 3M), compomer (Dyract Flow®, Dentsply) and Giomer (Beautifil®, Shofu) with 3MTM Single BondTM Universal Adhesive (SBU) (7th generation, self-etch, single solution adhesive) and AdperTM Single Bond 2 Adhesive (ASB) (5th generation, total-etch, two solution adhesive). MATERIALS AND METHODS: Sixty extracted human permanent teeth were collected, cleansed of debris, and placed in distilled water. The samples were segregated into two groups depicting the two bonding agents-AdperTM (ASB) and 3MTM Single Bond Universal (SBU) and sub-grouped into three groups depicting the three restorative materials (Composite, Giomer, and Compomer) used. Groups were respresented as follows: Group I-ASB + Composite; Group II-ASB + Giomer; Group III-ASB + Compomer; Group IV-SBU + Giomer; Group V-SBU + Compomer; Group VI-SBU + Composite. After applying the bonding agent as per the manufacturer's instructions, following which the restorative material was placed. A Universal Testing Machine (Instron 3366, UK) was employed to estimate the shear bond strength of the individual restorative material and shear bond strengths were calculated. RESULTS: Composite bonded with SBU (group VI) displayed the greatest shear strength (11.16 ± 4.22 MPa). Moreover, Giomers and flowable compomers displayed better bond strengths with ASB compared with their SBU-bonded counterparts. CONCLUSION: These results mark the importance of careful material selection in clinical practice and the bonding agent used to achieve optimal bond strength and enhance the clinical longevity and durability of dental restorations. CLINICAL SIGNIFICANCE: From a clinical perspective, to avoid a compressive or a shear failure, it would be preferrable to use a direct composite restorative material with SBU (Single bond universal adhesive, 7th generation) to achieve maximum bond strength. How to cite this article: Kuchibhotla N, Sathyamoorthy H, Balakrishnan S, et al. Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study. J Contemp Dent Pract 2024;25(3):245-249.

Shaping ability of three heat-treated NiTi systems in Vertucci's type III root canals of mandibular incisors: An ex vivo study.

Introduction: The anatomical configuration classified as Vertucci's type III is described as the second most prevalent in mandibular incisors. Methods: Thirty-six Vertucci's type III mandibular incisors were evaluated by micro-computed tomography (micro-CT) and divided into 3 groups (n = 12) according to the root canal preparation protocol (HyFlex CM [HCM], HyFlex EDM [HEDM], and Sequence Rotary File [SRF]). The teeth were scanned before and after performing 0.25 mm and 0.40 mm apical diameter preparations. The canal volume, dentin thickness, percentage of accumulated debris and untouched canal areas, transportation, and centering ability were measured. The data were statistically analyzed by ANOVA, Tukey, Kruskal-Wallis, and Dunn tests (P < 0.05). Results: The volume increase was more evident in the apical third. After 0.40 mm preparation, the SRF system provided a higher reduction (P < 0.05) in dentin thickness on the buccal surface 1 mm from the apex. There was higher canal transportation in the bucco-lingual direction. The 0.40 mm apical preparation reduced the percentage of untouched canal areas. The apical third had the highest percentage of untouched canal areas. The cervical third had the lowest volume of accumulated debris. Conclusions: Increasing the apical preparation to a diameter of 0.40 mm with the HCM, HEDM, and SRF systems in Vertucci's type III root canals of mandibular incisors proved to be safe and effective, reducing untouched canal areas. Clinical relevance: Root flattening can be intense to the point of generating a root canal bifurcation. Despite the decrease in the root canal diameter, a greater enlargement of the apical region is necessary and safe.

Comparative evaluation of remaining dentin thickness, canal centering ability and apical deformity between ProFit S3 and Protaper gold - A nano CT study.

Purpose: For the root canal treatment to be successful, the root canal system must be cleaned and shaped, and must be gradually widened from the apical to the coronal region in order to preserve dentin thickness. ProFit S3 (Profit Dental, India) patented rotary file with variable taper design preserves dentin. The study employs ultra-high-resolution nano-computed tomography to assess the volumetric changes of two new rotary files in permanent mandibular premolars. Materials and methods: Based on inclusion and exclusion criteria, this in-vitro investigation used extracted premolars. Before the pre-operative scan, samples were made and the working length was determined using a high-precision nano-CT (SkyScan 2214, Bruker, Kontich, Belgium). A single skilled pediatric dentist used ProFit S3 (Profit Dental, India) and Protaper Gold (PTG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) to prepare the canals. Post-op scans were similar to pre-ops. For 3D root canal visualization and analysis, NRecon software was used to rebuild images. Results: Profit S3 has a mean value of 0.65500 and Protaper gold 1.38800, indicating a significant range. Protaper gold followed Profit S3 in canal volume differential. The two rotating file systems differed significantly (p 0.05). ProFit S3 maintained mesiodistal and buccolingual dentin thickness at 4 mm, 8 mm, and 12 mm, followed by Protaper Gold. Conclusions: ProFit S3 exhibited the lowest mean canal volume difference compared to Protaper gold. Unlike Protaper Gold, ProFit S3 offers a variable taper design that preserves root canal anatomy, peri cervical dentin, and dentin thickness.

Utilizing partially demineralized dentin plate for horizontal ridge augmentation: A case report.

BACKGROUND: This article intends to showcase a case of guided bone regeneration (GBR) utilizing a partially demineralized dentin plate processed from an extracted second molar for horizontal augmentation of the posterior ridge for implant placement. METHODS AND RESULTS: A 60-year-old patient presented with horizontal ridge deficiency at site #30 and an endodontically treated tooth #31 with recurrent decay. A treatment plan was proposed to extract tooth #31 and utilize a dentin graft from the tooth for ridge augmentation at site #30. Following the atraumatic extraction of tooth #31, it was sectioned into a 1 mm thick dentin plate, sterilized, and processed to obtain a demineralized dentin graft. Following a mid-crestal incision and full-thickness flap elevation, the dentin plate was adapted on the buccal defect of site #30 with 10 mm fixation screws, and the gap between the plate and the buccal bone was filled with 0.5 cc of 50/50 cortico-cancellous bone allograft hydrated with saline, covered with collagen membrane followed by primary closure. At 6 months, a postoperative cone-beam computed tomography (CBCT) was obtained to evaluate the ridge width revealing sufficient ridge width for optimal implant placement. The radio-opaque dentin plate was visible on the CBCT depicting integration with the alveolar ridge. Following surgical implant preparation protocol, a 4 mm diameter and 8.5 mm length implant was placed in a restoratively driven position. CONCLUSION: This case reports favorable outcomes for GBR using a partially demineralized dentin plate as an alternative to an autogenous bone block graft for horizontal ridge augmentation for future implant placement. KEY POINTS: This case introduces a novel method utilizing partially demineralized dentin plates derived from extracted teeth for guided bone regeneration, showcasing its potential efficacy in addressing ridge deficiencies. Success, in this case, relies on meticulous sectioning of the tooth and processing of the dentin graft, precise adaptation and fixation of the graft to the residual ridge, and achieving primary closure for undisturbed healing. Limitations to success include the availability of teeth for extraction coinciding with the need for ridge augmentation and unstable graft fixation.

Effect of Simulated Dental Pulpal Pressure Using Fetal Bovine Serum for the Bonding Performance of Contemporary Adhesive to Dentin.

This study evaluated the effect of simulated pulpal pressure (SPP) conditions and storage time on contemporary adhesive systems' microtensile bond strength (µTBS) to dentin. Extracted human molars were prepared and randomly divided into four groups according to the adhesives: Clearfil Megabond 2 (CSE), Beautibond Xtreme Universal (BXU), G2-Bond (G2B), and Scotchbond Universal Plus (SBP). Each adhesive group was further divided following the SPP conditions: control with no simulation (SPP-CTR), SPP with distilled water (SPP-DTW), and SPP with fetal bovine serum (SPP-FBS). Resin composite build-ups were prepared, and teeth were stored in water (37 °C) for 24 h (24 h) and 3 months (3 m). Then, teeth were sectioned to obtain resin-dentin bonded beams and tested to determine the µTBS. Data were analyzed using three-way ANOVA, Tukey post hoc tests (=0.05), and Weibull failure analysis. Failure mode was observed using scanning electron microscopy. The µTBS response was affected by adhesive systems, simulated pulpal pressure conditions, and storage time. SPP-CTR groups presented a higher overall bond strength than SPP-DTW and SPP-FBS, which were not significantly different from each other. Only for SBP, the SPP-FBS group showed higher µTBS than the SPP-DTW group. The Weibull analysis showed that the bonding reliability and durability under SPP-DTW and SPP-FBS were inferior to SPP-CTR, and the 24 h bonding quality of adhesives to dentin was superior to that of 3 m. SPP drastically reduced the µTBS of all adhesives to dentin regardless of solution (distilled water or fetal bovine serum). Storage after 3 m also decreased µTBS despite the SPP condition.

Long-term haplodeficency of DSPP causes temporomandibular joint osteoarthritis in mice.

BACKGROUND: Extracellular matrix (ECM) protein malfunction or defect may lead to temporomandibular joint osteoarthritis (TMJ OA). Dentin sialophophoprotein (DSPP) is a mandibular condylar cartilage ECM protein, and its deletion impacted cell proliferation and other extracellular matrix alterations of postnatal condylar cartilage. However, it remains unclear if long-term loss of function of DSPP leads to TMJ OA. The study aimed to test the hypothesis that long-term haploinsufficiency of DSPP causes TMJ OA. MATERIALS AND METHODS: To determine whether Dspp+/- mice exhibit TMJ OA but no severe tooth defects, mandibles of wild-type (WT), Dspp+/-, and Dspp homozygous (Dspp-/-) mice were analyzed by Micro-computed tomography (micro-CT). To characterize the progression and possible mechanisms of osteoarthritic degeneration over time in Dspp+/- mice over time, condyles of Dspp+/- and WT mice were analyzed radiologically, histologically, and immunohistochemically. RESULTS: Micro-CT and histomorphometric analyses revealed that Dspp+/- and Dspp-/- mice had significantly lower subchondral bone mass, bone volume fraction, bone mineral density, and trabecular thickness compared to WT mice at 12 months. Interestingly, in contrast to Dspp-/- mice which exhibited tooth loss, Dspp+/- mice had minor tooth defects. RNA sequencing data showed that haplodeficency of DSPP affects the biological process of ossification and osteoclast differentiation. Additionally, histological analysis showed that Dspp+/- mice had condylar cartilage fissures, reduced cartilage thickness, decreased articular cell numbers and severe subchondral bone cavities, and with signs that were exaggerated with age. Radiographic data showed an increase in subchondral osteoporosis up to 18 months and osteophyte formation at 21 months. Moreover, Dspp+/- mice showed increased distribution of osteoclasts in the subchondral bone and increased expression of MMP2, IL-6, FN-1, and TLR4 in the mandibular condylar cartilage. CONCLUSIONS: Dspp+/- mice exhibit TMJ OA in a time-dependent manner, with lesions in the mandibular condyle attributed to hypomineralization of subchondral bone and breakdown of the mandibular condylar cartilage, accompanied by upregulation of inflammatory markers.

Construction of dentin-on-a-chip based on microfluidic technology and tissue engineering.

AIM: Three-dimensional (3D) cell culture systems perform better in resembling tissue or organism structures compared with traditional 2D models. Organs-on-chips (OoCs) are becoming more efficient 3D models. This study aimed to create a novel simplified dentin-on-a-chip using microfluidic chip technology and tissue engineering for screening dental materials. METHODOLOGY: A microfluidic device with three channels was designed for creating 3D dental tissue constructs using stem cells from the apical papilla (SCAP) and gelatin methacrylate (GelMA). The study investigated the effect of varying cell densities and GelMA concentrations on the layer features formed within the microfluidic chip. Cell viability and distribution were evaluated through live/dead staining and nuclei/F-actin staining. The osteo/odontogenic potential was assessed through ALP staining and Alizarin red staining. The impact of GelMA concentrations (5 %, 10 %) on the osteo/odontogenic differentiation trajectory of SCAP was also studied. RESULTS: The 3D tissue constructs maintained high viability and favorable spreading within the microfluidic chip for 3-7 days. A cell seeding density of 2 × 104 cells/µL was found to be the most optimal choice, ensuring favorable cell proliferation and even distribution. GelMA concentrations of 5 % and 10 % proved to be most effective for promoting cell growth and uniform distribution. Within the 5 % GelMA group, SCAP demonstrated higher osteo/odontogenic differentiation than that in the 10 % GelMA group. CONCLUSION: In 3D culture, GelMA concentration was found to regulate the osteo/odontogenic differentiation of SCAP. The study recommends a seeding density of 2 × 104 cells/µL of SCAP within 5 % GelMA for constructing simplified dentin-on-a-chip. CLINICAL SIGNIFICANCE: This study built up the 3D culture protocol, and induced odontogenic differentiation of SCAP, thus forming the simplified dentin-on-a-chip and paving the way to be used as a well-defined biological model for regenerative endodontics. It may serve as a potential testing platform for cell differentiation.

Efficacy of seventh generation bonding agents as desensitizers in patients with dentin hypersensitivity: a randomized clinical trial.

BACKGROUND: Dentin hypersensitivity (DH) is one of the most challenging and persistent dental complaints characterized by transient, intense pain triggered by various stimuli. It affects a significant portion of the global population, predominantly those aged 20-40. This study aims to evaluate the desensitizing efficacy of seventh-generation dentin bonding agents (Single Bond Universal by 3 M ESPE and Xeno-V + by Dentsply) against a control group using Bifluorid 12 by Voco in mitigating DH within a month of the follow-up period. METHODS: This was a single-center, parallel-group, double-blind, controlled randomized clinical trial conducted at Dow University of Health Sciences, Karachi, Pakistan. A total of 105 patients with DH were allocated into three groups for this study. The patients were divided into three groups (Single Bond Universal by 3 M ESPE and Xeno-V + by Dentsply) and the control group containing fluoride varnish (Bifluorid 12 by Voco). Discomfort Interval Scale scores and Schiff Cold Air Sensitivity Scale scores were recorded at baseline, immediately after the intervention, after 01 weeks, and after 01 month. RESULTS: All the materials demonstrated a statistically significant reduction in discomfort and sensitivity (DIS scores p-value 0.01) immediately after 01 week and over a period of 01 month after treatment compared with the baseline scores before application, with no single material proving superior over the one-month observation period. The study also provided insights into dental hygiene practices, with a significant majority using a toothbrush and sensitivity patterns, with cold stimuli being the most common cause of sensitivity. CONCLUSION: The study demonstrates that Single Bond Universal, Xeno V+, and Bifluorid 12 are equally effective in reducing dentin hypersensitivity, with no distinct superiority observed over a one-month period. The findings highlight the potential of fluoride varnishes as a less technique-sensitive and cost-effective option for treating DH, offering valuable insights for future research and clinical practice. TRIAL REGISTRATION: NCT04225247 ( https://clinicaltrials.gov/study/NCT04225247 ), Date of Registration: 13/01/2020. (Retrospectively registered).

Phycocyanin-loaded silver nanoparticles activated with photodynamic therapy and Nd: YAG laser for caries-affected dentin disinfection: Impact on Streptococcus mutans survival rate and shear bond strength to the tooth-colored restorative material.

AIMS: To assess the impact of various cavity disinfectants PC-PDT (Phycocyanin activated by Photodynamic therapy), PC@AgNPs-PDT (Phycocyanin and silver nanoparticles activated by PDT), and Nd: YAG laser on the survival rate of S.mutans and the bond integrity of composite restoration METHODS: Sixty human mandibular molars that scored 4 and 5 based on ICDAS criteria were included. The infected dentin was removed while the CAD was preserved based on visual, tactile, and staining assessment. S.mutans were cultured on the CAD of twenty samples. All the specimens were indiscriminately distributed into four groups based on cavity disinfection (n=20 each includes n = 5 each group incubated with S.mutans) Group 1: CHX, Group 2: Nd:YAG laser, Group 3: PC-PDT and Group 4: PC@AgNPs-PDT. S.mutans survival rate was assessed for each group(n = 5). Forty samples underwent composite bonding for SBS and failure mode assessment using universal testing machine (UTM) and stereomicroscope. The calculations for the mean and standard deviation (SD) and their comparison among different groups were performed using a one-way analysis of variance (ANOVA) and the Tukey post hoc test (p ≤ 0.05) RESULTS: CAD surface treated disinfected with PC@AgNPs-PDT yielded the lowest survival rates (0.13 ± 0.05 CFU/ml) and highest SBS (17.23 ± 1.45 MPa). Group 1 (CHX) unveiled the highest survival rate of S.mutans (0.33 ± 0.12 CFU/ml). However, Group 2 (Nd:YAG Laser) (11.87 ± 0.67 MPa) presented the lowest SBS CONCLUSION: The combination of Phycocyanin loaded with silver nanoparticles and activated with Photodynamic therapy demonstrates the highest antimicrobial potential and bond strength of composite restorations.

Does an incomplete ferrule affect the fracture of endodontically treated teeth? A systematic review of in vitro studies.

OBJECTIVE: The purpose of this systematic review was to assess the impact of the incomplete ferrule on the fracture of endodontically treated teeth (ETT). DATA: The keywords such as "incomplete ferrule," "ferrule," "ferrule effect," "residual dentin," "remaining dentin," or "remaining coronal dentin" were used for searching, and only in vitro studies investigating the incomplete ferrule effect on natural teeth were included. SOURCES: PubMed, Medline, Embase, Cochrane Library, and Science Direct databases, and manual-searching. STUDY SELECTION: The search strategy yielded 1633 hits, and a total of 19 in vitro studies closely related to the effect of incomplete ferrule on ETT were included. CONCLUSION: The presence of an incomplete ferrule may significantly increase the fracture resistance of restored ETT, compared with restored ETT without ferrule. The number of residual axial walls of the incomplete ferrule may have an impact on the fracture resistance and fracture mode. The location of residual axial walls of the incomplete ferrule may affect the fracture resistance but not the fracture mode. CLINICAL IMPLICATIONS: Limited data suggest that the presence of incomplete ferrule has a positive effect on the fracture resistance of restored ETT. An incomplete ferrule can be an alternative for restoring ETT when a complete ferrule is not present. Nevertheless, further high-quality studies are still needed to offer more robust evidence and to take potential confounding factors into account.