Optical coherence tomography (OCT) is a noninvasive technique providing cross-sectional images of a tooth structure. This review describes the use of OCT for detecting dental caries, tooth fractures, and interfacial gaps in intraoral restorations. OCT can be a reliable and an accurate method and a safer alternative to X-ray radiography.

No abstract

This study evaluated bonding of adhesives to dentin treated with silver diammine fluoride (SDF). Micro-shear bond strength (MSBS) to sound human dentin was investigated for 3 adhesive systems: Clearfil SE bond 2 (CSE), and Scotchbond Universal in self-etching (SBU) and phosphoric acid-etching (SBT) modes, following 4 different SDF application protocols (n=10); Control: treated with deionized water. P1: SDF applied for 10-s, no rinse. P2: SDF applied for 10-s, rinsed off after 1-min. P3: superficial dentin polished off after 24-h following P1. MSBS data were obtained after 24-h water storage at 37°C. SDF significantly affected MSBS to dentin depending on the SDF protocol and adhesive system. Rinsing SDF off improved bond strength but superficial refreshing of SDFtreated dentin prior to bonding showed the highest bond strength. The two-step self-etch adhesive (CSE) and the universal adhesive in acid-etching mode (SBT) showed better performance than universal adhesive (SBU) alone on SDF treated dentin.

SUMMARY This article describes the clinical protocol of using potassium iodide (KI) to reverse staining caused by silver diamine fluoride (SDF). SDF contains silver, fluoride, and ammonia. It has been used to arrest dental caries mainly in pediatric applications. The major drawback of SDF application is the dark staining of both teeth and restorative materials. Hence, its use on adult dentition is limited. Improving the esthetic outcome by stain reduction would greatly enhance the opportunity for SDF's universal use. This case demonstrates how KI can effectively reverse the staining.

No abstract

Background: Since the introduction of resin composites, the staining of resin-based materials by colored solutions such as coffee, tea, chlorhexidine (CHX), and other beverages has become a common concern. Aim: The aim of this study was to evaluate the effect of home and office bleaching as a treatment for discoloration of composite after immersion in coffee or CHX. Materials and Methods: A microhybrid composite (Z250), nanohybrid composite (Z550), and nanofill composite (ultimate, body shade) were selected. Forty disk shape specimens (8 mm diameter and 2 mm thickness) for each composite were prepared then divided into two groups according to staining solutions (25 g of coffee in 250 ml water, 20 min/day or 0.2% CHX, 1 min/day). Following 1 month staining, specimens were divided into two groups again. Half of the specimens was bleached with in office bleaching agent (Opalescence Boost 40% hydrogen peroxide concentration) 3 times in one visit for 15minutes and the others subjected to home bleaching agent(Opalescence 10% carbamide peroxide) 6h/day until 2 weeks both from Ultradent Products, Inc., South Jordan, UT, USA. Color of the specimens was measured with a spectrophotometer using CIELAB color space at baseline, after 1 month staining, and after ending the bleaching process. Statistical Analysis: Analysis of variance was used to analyze the data ( P < 0.05). Results: Coffee and CHX provided significant color changes in all groups ( P < 0.05). Z550 was the material more prone to discoloration in coffee in comparison with Filtek Ultimate ( P = 0.003). After bleaching, materials showed significant reduction except stained Z550 by coffee in home bleaching groups. Both home and office bleaching provided significant color changes in all CHX groups ( P < 0.05). Conclusion: Coffee produced more color changes than CHX. The hydrogen peroxide has the same whitening effect in comparison with carbamide peroxide.

Using micro-computed tomography (micro-CT), this study assessed the inhibitory effect of three different types of restorations on root-caries formation under a cariogenic challenge. Bovine-root dentin blocks with a cylindrical cavity were divided into three restoration groups: a fluoride-free self-etch adhesive and a resin composite (SE-ES); a self-etch adhesive and a resin composite with multi-ion release (FL-BF); and a glass ionomer cement (Fuji-VII). After the restorative procedures, the specimens were stored in artificial saliva for 1 d, then subjected to a demineralization solution for 4 d and a remineralization solution for 28 d. Mineral density and mean mineral loss of dentin around the restorations were measured using micro-CT. The mean mineral loss values of dentin around the restorations were highest among SE-ES restorations and lowest among Fuji-VII restorations. Fuji-VII showed the highest mineral density and the lowest mineral loss after 28 d of remineralization. The observations made by scanning electron microscopy demonstrated that Fuji-VII created the smallest outer lesion followed by FL-BF and SE-ES. Fuji-VII has a larger inhibitory effect on root caries around the restorations and enhances remineralization more effectively than either FL-BF or SE-ES. Multi-ion and fluoride release from the restorative materials may be beneficial for inhibition of root-dentin caries around the restorations.

Gingiva is the soft tissue that surrounds and protects the teeth. Healthy gingiva provides an effective barrier to periodontal insults to deeper tissue, thus is an important indicator to a patient's periodontal health. Current methods in assessing gingival tissue health, including visual observation and physical examination with probing on the gingiva, are qualitative and subjective. They may become cumbersome when more complex cases are involved, such as variations in gingival biotypes where feature and thickness of the gingiva are considered. A noninvasive imaging technique providing depth-resolved structural and vascular information is necessary for an improved assessment of gingival tissue and more accurate diagnosis of periodontal status. We propose a three-dimensional (3D) imaging technique, optical coherence tomography (OCT), to perform in situ imaging on human gingiva. Ten volunteers (five male, five female, age 25-35) were recruited; and the labial gingival tissues of upper incisors were scanned using the combined use of state-of-the-art swept-source OCT and OCT angiography (OCTA). Information was collected describing the 3D tissue microstructure and capillary vasculature of the gingiva within a penetration depth of up to 2 mm. Results indicate significant structural and vascular differences between the two extreme gingival biotypes (ie, thick and thin gingiva), and demonstrate special features of vascular arrangement and characteristics in gingival inflammation. Within the limit of this study, the OCT/OCTA technique is feasible in quantifying different attributes of gingival biotypes and the severity of gingival inflammation.