Performance evaluation of carbon quantum dots impregnated glass ionomer cement to avoid peri-implant disease.

Dental cement residues exacerbate peri-implant tissue irritation and peri-implantitis. The present study aims to evaluate the cytotoxicity, physiochemical, optical, and rheological properties of carbon quantum dots (CQDs) impregnated glass ionomer cement (GIC). Surface passivated fluorescent CQDs were synthesized using citric acid via thermal decomposition and blended with GIC. Characterization studies and rheological measurements were made to evaluate their performance. 3D-printed dental implant models cemented with GIC and GIC-CQD were compared to analyze excess cement residues. MTT assay was performed with human dental pulp stem cells (hDPSCs) and statistically analyzed using ANOVA and Tukey's test. CQDs with a particle dimension of ∼2 nm were synthesized. The amorphous property of GIC-CQD was confirmed through XRD. The fluorescence properties of GIC-CQD showed three times higher emission intensity than conventional GIC. GIC-CQD attained maturation with a setting time extended by 64 s than GIC. Cement residue of size 2 mm was detected with a UV light excitation at a distance between 5 to 10 cm. Biocompatibility at 0.125 mg ml-1dilution concentrations of GIC-CQD showed viability greater than 80% to hDPSCs. For the first time, we report that CQDs-impregnated GIC is a unique and cost-effective strategy for in-situ detection of excess cement rapidly using a hand-held device. A novel in-situ rapid detection method enables the dentist to identify residual cement of size less than 2 mm during the implantation. Therefore, GIC-CQD would replace conventional GIC and help in the prevention of peri-implant diseases.

Dimensional Stability and Retention Strength of Impressions to Custom Impression Trays Fabricated Using Conventional Method and Additive Technology - An In-vitro Study.

BACKGROUND: 3D printing technology is replacing manual fabrication in all fields. 3D-printed impression trays should be assessed as they could replace conventional impression trays in the future. AIM: In-vitro comparison and evaluation of the dimensional stability and retention strength of impressions to custom impression trays fabricated using conventional method and additive technology. MATERIALS AND METHODS: A maxillary edentulous auto-polymerizing acrylic resin model served as the master model. Two moulds were prepared from the master model in order to obtain 12 casts. One cast was scanned for 3D printing digital light processing (DLP) and fused deposition modelling (FDM) 24 impression trays using polylactic acid (PLA). Twelve casts were used to fabricate light cure impression trays. Polyvinyl-siloxane impressions were made on the master model using 36 impression trays and 18 trays each were used to assess dimensional stability and retention strength. RESULTS: In dimensional stability analysis, one sample t-test revealed a statistically significant difference between each group and the master model followed by a one-way ANOVA. There were significant differences, but the difference was less with FDM trays (P < 0.05). In retention strength analysis, one-way Analysis of variance (ANOVA) revealed statistically significant difference between each group and post-hoc test revealed specific difference, the highest with FDM trays (P < 0.05). CONCLUSION: Dimensional changes were observed at 30 minutes and 72 hours. Lesser dimensional changes were observed when impressions were made using FDM trays followed by DLP and light cure trays. The mean retention strength seen in descending order was FDM, followed by DLP and light cure trays. The best retention strength was noticed when impressions were made using FDM trays.

Preliminary impressions in microstomia patients: an innovative technique.

Microstomia has been defined as an abnormally small oral orifice associated with various etiopathologic factors. Management of these patients poses extreme difficulties in every procedure during prosthesis fabrication. Restricted mouth opening of the patient makes the insertion and the removal of the tray extremely difficult. So sectioning of the existing stock tray is necessary, so that the trays can be inserted and removed in sections. The main problem encountered during this procedure is the reorientation of the tray back in position. This article presents an innovative technique for the easy handling of the sectioned stock impression trays.

Direct metal laser sintering: a digitised metal casting technology.

Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons.

Periapical radiolucency not requiring endodontic therapy: an unusual case.

The article is a case report of an unusual manifestation of primary hyperparathyroidism seen in the mandible. Primary hyperparathyroidism is a rare disorder that can present its first symptoms in the jaws. The pre- and post-treatment radiographic features of such cases have only rarely been reported in dental literature. This case report highlights the importance of careful clinical and radiographic examination before commencing root canal treatment.

Alginate impressions: A practical perspective.

The choice of an impression material for a particular situation depends on the treatment being provided, operator preference, and so on. Even with the introduction of more advanced and more accurate rubber base impression materials, irreversible hydrocolloid impression materials have stood the test of time. This article gives a detailed perspective of how best to make alginate impressions.