Dentin tubule occlusion by a 38% silver diamine fluoride gel: an in vitro investigation

Objective Silver diamine fluoride (SDF) is effective in treatment of dentin hypersensitivity and caries lesions. However, the non-viscous solution does not easily allow clinicians to control the application area. A 38% SDF experiment gel was compared in vitro to commercial SDF for its ability to penetrate and occlude dentinal tubules. Materials and methods Human root surface dentin specimens were treated with gelled or standard 38% SDF or negative control. Penetration behavior was established by Drop Shape Analysis. Precipitates at the surface and within tubules were analyzed by SEM and EDX after treatment; Results: penetration depths up to 500 µm were observed for both SDF formulations. Both formulations occluded dentinal tubules similarly. Precipitates on the dentin surface and within dentinal tubules were found for both SDF formulations, with a slight tendency for the experimental gel SDF product to be more abundant than the commercially available one. Discussion: behavior of the experimental 38% SDF gel formulation appeared indistinguishable from the commercial 38% SDF product with respect to dentinal tubule penetration and occlusion. Conclusions The experimental 38% SDF gel may be a suitable intervention for the prevention of dentin hypersensitivity.

Electrophoresis-Aided Biomimetic Mineralization System Using Graphene Oxide for Regeneration of Hydroxyapatite on Dentin

Graphene oxide (GO) is an emerging luminescent carbon nanomaterial with the ability to foster hydroxyapatite (HA). A specially designed electrophoresis system can be used to accelerate the mineralization process. The aim of this study was to promote HA crystal growth on demineralized dentin using a GO incorporated electrophoresis system. GO was successfully synthesized by carbonization of citric acid and its presence was confirmed by Fourier transform infrared and UV-visible spectrophotometry evaluation. Dentin slices were placed in demineralized solution and divided into control (without the electrophoresis system) and experimental group. Demineralized dentin slices in the experimental group were remineralized using the electrophoresis system for 8 h/1.0 mA, with one subgroup treated without GO and the other with GO. Energy dispersive spectroscopy evaluation showed that the calcium/phosphate ratio of the crystal formed in control and experimental group with addition of GO was close to natural hydroxyapatite. However, scanning electron microscopy evaluation showed that the exposed dentinal tubules were occluded with rod-like crystals, which is similar to native enamel morphology, in the experimental group with addition of GO compared to the flake-like crystal in the control group. Mechanical evaluation revealed that the nanohardness and modulus of remineralized dentin were significantly higher in the experimental group. In conclusion, GO is a promising material to remineralize dentin and the introduction of an electrophoresis system can accelerate its process.

Evaluation of a Hypersensitivity Inhibitor Containing a Novel Monomer That Induces Remineralization—A Case Series in Pediatric Patients

Background: Recently, tooth deformities have been frequently encountered by pediatric dentists. Severe enamel hypomineralization sometimes induces pain such as hyperesthesia, but composite resin restoration is difficult because it often detaches without any cavity preparation. Resin-based hypersensitivity inhibitors for tooth physically seal the dentinal tubules. It was reported that hypersensitivity inhibitor containing novel adhesive monomers forms apatite and induces remineralization in vitro. Therefore, these clinical trials assessed the clinical effects of remineralization and the suppression of hypersensitivity by the new agent. Methods: After mechanical tooth cleaning was performed, the hypersensitivity inhibitors were applied and cured by light exposure. Changes in hypersensitivity were determined by visual analog scale (VAS). The improvement of hypomineralization was evaluated by the change in color tone based on the digital images of intraoral photographs. Results: After repeated monthly treatments, these cases showed decreased hypersensitivity after the fourth application, while the opaque white and brownish color improved on the seventh application. Conclusion: This novel hypersensitivity inhibitor with C-MET and MDCP not only suppressed hypersensitivity but also improved cloudiness and brown spots in immature permanent teeth in presented cases.

Effect of Aluminum Chloride Hemostatic Agent on Bonding Strength of RMGIC in Primary Tooth

The purpose of this study was to evaluate the effect of a hemostatic agent containing aluminum chloride on the shear bond strength of resin-modified glass ionomer cement (RMGIC) to the dentin of primary teeth. Thirty-six extracted non-carious human primary teeth were collected in this study. Dentin surfaces were cut and polished. The specimens were randomly divided into 4 groups; group I: RMGIC without conditioning; group II: polyacrylic acid (PAA), RMGIC; group III: aluminum chloride, RMGIC; group IV: aluminum chloride, PAA, RMGIC. All teeth were thermocycled between 5.0℃ and 55.0℃ for 5000 cycles. Fifteen specimens from each group were subjected to shear bond strength test and 3 specimens from each group were inspected using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. The mean shear bond strength of each group was as follows: 4.04 ± 0.88 MPa in group I, 8.29 ± 1.40 MPa in group II, 1.39 ± 0.47 MPa in group III, 6.24 ± 2.76 MPa in group IV. There were significant differences among all groups (p < 0.001). SEM image of the dentinal tubules were partially exposed in group III and group IV. Fully exposed dentinal tubules were found in group II. In conclusion, aluminum chloride decreased the shear bond strength of RMGIC to dentin, regardless of PAA conditioning.

Histological Evaluation of Multisonic Technology for Debridement of Vital and Necrotic Pulp Tissues from Human Molar Teeth. An Observational Study

Background: This study evaluated the efficacy of a multisonic technology for the debridement of vital and necrotic pulp tissues in freshly extracted human mandibular molar teeth. Methods: Twelve teeth with a diagnosis of symptomatic irreversible pulpitis (SIP) and twelve teeth with a diagnosis of pulp necrosis with symptomatic apical periodontitis (SAP) were extracted. The GentleWave® procedure was performed on 10 teeth from each group. Four non-treated teeth served as histologic controls. Histological consecutive 5 µm sections were obtained from the apical, middle, and coronal portion of the canals. The canals were evaluated for the presence of pulpal debris and bacteria. Results: In nine out of the ten specimens with SIP, no pulpal debris was detected in any portion of the canals. In the necrotic pulp group, eight out of the ten specimens had no detectable pulpal debris in any portion of the canal spaces. No bacteria were detected in the main canals, isthmuses, or lateral canals, but were detected deep within the dentinal tubules in 10 specimens. Conclusions: This study demonstrated that the multisonic technology was effective at removing vital and necrotic pulp tissue as well as bacteria from the root canal system, including inaccessible areas.

“COMPARATIVE EVALUATION OF EFFECT ON DENTINAL TUBULE OCCLUSION BY THREE DIFFERENT DESENSITIZING DENTIFICES: A SEM STUDY”

Introduction: Dentine hypersensitivity (DH) occurs on exposed dentine and is dependent on the patency of dentinal tubules. This study compared the effectiveness of toothpaste containing Strontium Chloride, Novamine, Pro-Arginine in occluding dentine tubules along with comparision of those. Materials and Method: 45 freshly extracted teeth were randomly divided (15 each) into 3 groups: Group 1 15 Teeth treated with toothpaste containing Strontium Chloride. Group 2 15 Teeth treated with toothpaste containing Novamine Group 3 15 Teeth treated with toothpaste containing Pro-Arginine. Each specimen was brushed with the dentifrice slurries and examined under SCM. Result: The mean of occluded dentinal tubules on the dentin surface after brushing with three dentifrices were significant among them Pro-arginine group showed maximum occlusion. Conclusion: The present in vitro SEM study results revealed that: All the experimental agents– Strontium chloride, novamin, Pro- Argenine were effective in occluding dentinal tubules & the percentage (%) of occluded tubules was found to be highest for Pro- Argenine as compared to the other groups. Keywords: SCM, DH

Enamel Remineralization and Dentine Tubules Occlusion by Bioactive Formulations Based on Ion-Doped Nanohydroxyapatite and Precursor Nanoparticles.

Recent health care products are based on formulations claimed to provide enamel remineralization and dentinal tubules occlusion through calcium-phosphate bioactive nanocompounds ( ion-doped hydroxyapatite and precursor nanoparticles). This study aimed to test and characterize for the first time the structure and composition of a representative sample of remineralizing toothpastes and topical mousses available on the market. The enamel remineralization and dentinal tubules occlusion efficacy of tested formulations were investigated in vitro. Formulations were characterized in terms of water- and acid-insoluble fractions, and PXRD, FTIR, and EDS analyses were performed to determine their composition and investigate the presence of bioactive compounds and doping elements. All formulations containing Ca-P bioactive nanocompounds showed remineralizing ability, notably when hydroxyapatite and amorphous calcium phosphate compounds were doped with small amounts of CO3-, F, Mg, and Sr. Topical mousse formulations showed a higher tubules occlusion capability than toothpastes, independently from their composition. In conclusion, all tested formulations could express remineralizing potential both on enamel and dentin thanks to the presence of biomimetic Ca-P compounds. The presence of doping elements or CPP-ACP seems essential to allow such performances.

The Antibacterial and Remineralization Effect of Silver-Containing Mesoporous Bioactive Glass Sealing and Er-YAG Laser on Dentinal Tubules Treated in a Streptococcus mutans Cultivated Environment

The aim of this study was to evaluate the remineralization and antibacterial effect of silver-containing mesoporous bioactive glass (MBG-Ag) sealing combined with Er:YAG laser irradiation on human demineralized dentin specimens in a Streptococcus mutans cultivated environment. A total of 48 human dentin specimens were randomly divided into four groups. The characteristics of MBG-Ag and the occlusion efficiency of the dentinal tubules were analyzed using X-ray diffraction patterns, Fourier-transform infrared spectroscopy, scanning electron microscope images and energy dispersive X-ray spectroscopy. Moreover, the antibacterial activity against Streptococcus mutans was evaluated by colony formation assay. The results showed that the dentin specimens with Er:YAG laser irradiation can form a melted occlusion with a size of 3–4 µm. MBG-Ag promoted the deposition of numerous crystal particles on the dentinal surface, reaching the deepest penetration depth of 70 μm. The results suggested that both MBG-Ag and laser have the ability to enhance the remineralization and precipitation of hydroxyapatite crystals. While the results showed that MBG-Ag sealing combined with the thermomechanical subablation mode of Er:YAG laser irradiation-induced dense crystalline deposition, reaching a penetration depth of more than 300 µm, silver nanoparticles without good absorption of the Er:YAG laser resulted in a heterogeneous radiated surface. Er:YAG laser irradiation with a low energy and pulse rate cannot completely inhibit the growth of S. mutans, but MBG-Ag sealing reached the bactericidal concentration. It was concluded that the simultaneous application of MBG-Ag sealing and Er:YAG laser treatment can prevent the drawbacks of their independent uses, resulting in a superior form of treatment for dentin hypersensitivity.

Mouse Dspp frameshift model of human dentinogenesis imperfecta

Non-syndromic inherited defects of tooth dentin are caused by two classes of dominant negative/gain-of-function mutations in dentin sialophosphoprotein (DSPP): 5′ mutations affecting an N-terminal targeting sequence and 3′ mutations that shift translation into the − 1 reading frame. DSPP defects cause an overlapping spectrum of phenotypes classified as dentin dysplasia type II and dentinogenesis imperfecta types II and III. Using CRISPR/Cas9, we generated a Dspp−1fs mouse model by introducing a FLAG-tag followed by a single nucleotide deletion that translated 493 extraneous amino acids before termination. Developing incisors and/or molars from this mouse and a DsppP19L mouse were characterized by morphological assessment, bSEM, nanohardness testing, histological analysis, in situ hybridization and immunohistochemistry. DsppP19L dentin contained dentinal tubules but grew slowly and was softer and less mineralized than the wild-type. DsppP19L incisor enamel was softer than normal, while molar enamel showed reduced rod/interrod definition. Dspp−1fs dentin formation was analogous to reparative dentin: it lacked dentinal tubules, contained cellular debris, and was significantly softer and thinner than Dspp+/+ and DsppP19L dentin. The Dspp−1fs incisor enamel appeared normal and was comparable to the wild-type in hardness. We conclude that 5′ and 3′ Dspp mutations cause dental malformations through different pathological mechanisms and can be regarded as distinct disorders.