Dosimetric parameters and radiotherapy simulation methods used in preclinical studies of radiation damage to the dentition: a systematic review.

Objective: This systematic review investigated the dosimetric parameters used in preclinical studies.

Study Design: Searches were performed in 3 databases (PubMed, Scopus, and Embase) and gray literature to identify studies for review. In vitro and ex vivo studies that examined the effect of radiation on human permanent teeth were included.

Acid dissolution of ultrathin glass-ceramic and its correlation with flexural strength.

Statement Of Problem: When glass-ceramics are treated with hydrofluoric acid (HF), not only the area of application is affected but also other surfaces. Information regarding the correlation of the dissolution caused by HF and the flexural strength of the ceramic is lacking.

Purpose: The purpose of this in vitro study was to investigate the effect of HF etching protocols on the flexural strength of 2 glass-ceramics, the correlation of their flexural strength with the internal and lateral dissolution, and the differences in Weibull characteristics concerning the etching protocols.

Over 300 Radiation Caries Papers: Reflections From the Rearview Mirror.

Radiation caries (RC) is an aggressive oral toxicity in head and neck cancer survivors, which develops 6 to 12 months after head and neck radiotherapy. It initially affects the tooth cervical/incisal surfaces, and if not promptly diagnosed/managed, progresses to dental crown amputation and risk of osteoradionecrosis. It results from a multidimensional cluster of treatment-induced oral symptoms, including hyposalivation, dietary changes, and oral hygiene impairment.

Dissolution Depth and Surface Morphological Alterations in Ultrathin Glass Ceramic Etched with Different Hydrofluoric Acid-etching Protocols.

Purpose: To evaluate the effect of different HF-etching protocols on the dissolution depth and micromorphology of the etched and adjacent surfaces of ultrathin glass-ceramic specimens.

Materials And Methods: One hundred twenty specimens (6 x 6 x 0.3 mm) of leucite-reinforced glass-ceramic (LEU, IPS Empress, Ivoclar Vivadent) and lithium-disilicate-reinforced glass-ceramic (LD, IPS e.

Awareness of the risk of radiation-related caries in patients with head and neck cancer: A survey of physicians, dentists, and patients.

Objectives: Radiation-related caries (RRC) is one of the most aggressive complications of radiotherapy (RT) in survivors of head and neck cancer (HNC). Lack of RRC awareness may contribute to the occurrence of this oral cavity complication. RRC may be considered a "forgotten oral complication" by patients with HNC, oncologists, and dentists.

Impact of head and neck radiotherapy on the longevity of dental adhesive restorations: A systematic review and meta-analysis.

Statement Of Problem: Established restorative protocols for patients after head and neck radiotherapy are lacking, increasing the failure rates of dental adhesive restorations.

Purpose: The purpose of this systematic review and meta-analysis was to analyze the evidence regarding the impact of head and neck radiotherapy on the longevity of dental adhesive restorations.

Material And Methods: A search was performed using PubMed, Scopus, and Embase in May 2018 (updated in November 2020).

Impact of dietary acids on the surface roughness and morphology of composite resins.

This in vitro study was performed to evaluate the surface roughness (Ra) and morphology by scanning electron microscopy (SEM) of composite resins that had been stored in acidic solutions typical of those present in the diet. Three composite resins (4 Seasons, Z250, and P90) were selected and divided into three groups (n = 7) according to the solutions tested: G1: distilled water; G2, Coca-cola, and G3: orange juice. The Ra test was repeated after immersion periods of 15, 90, and 180 days.

Radiation-related caries: current diagnostic, prognostic, and management paradigms.

Objective And Study Design: This narrative review summarizes the current state of art of radiation-related caries (RC), an aggressive disease that affects approximately 30% of post-head and neck radiotherapy (HNRT) patients.

Results: RC mainly affects the tooth cervical areas and incisal/cuspal tips and develops 6 to 12 months after HNRT. Early RC signs include black/brownish tooth discoloration and enamel cracks, which progress to enamel delamination, exposing underlying dentin to a highly cariogenic oral environment and rapid tooth destruction/dental crown amputation.

Massive extrusion of calcium hydroxide paste containing barium sulphate during endodontic treatment.

A 31-year-old woman was referred for the evaluation of persistent lower lip numbness following endodontic treatment of tooth #36. Imaging examinations showed a large amount of radiopaque/hyperdense material spread in an angiographic distribution in the left mandibular body region. Laboratory analyses of tooth #36 and adjacent periapical tissue, surgically extracted in an external Service due to acute pain following endodontic treatment, identified chronic inflammatory reaction and birefringent crystalloid foreign bodies rich in barium and sulphur, leading to the diagnosis of alveolar nerve injury due to accidental extrusion of intracanal dressing material composed of calcium hydroxide [Ca(OH) ] paste incorporated with barium sulphate.

Effect of cleaning protocol on silica deposition and silica-mediated bonding to Y-TZP.

Objectives: To evaluate the effect of cleaning methods on the deposition of silica on yttria-stabilized zirconium dioxide (Y-TZP) surface and on the silane-silica mediated bond strength between Y-TZP and resin cement.

Methods: Y-TZP slabs were air-abraded with 30μm silica-coated alumina particles and distributed in three groups: no cleaning, cleaning with a stream of oil-free air/water spray for 5s and cleaning with an ultrasonic bath in water for 10min. The distribution of Si on the Y-TZP surfaces was recorded using energy dispersive spectroscopy (EDS).

Bond Strength of CAD/CAM Restorative Materials Treated with Different Surface Etching Protocols.

Purpose: To evaluate the effect of different surface treatments on the surface morphology of CAD/CAM ceramics and on their bond strength to cement.

Materials And Methods: Sixty cubic sections were cut from each of three materials (lithium disilicate glass-ceramic [DL], leucite-based glass-ceramic [LC], resin-matrix ceramic composite [RMCC]) and were treated as follows (n = 10): 1. no treatment (C); 2.

Effect of silane and MDP-based primers on physico-chemical properties of zirconia and its bond strength to resin cement.

Objective: To evaluate the effect of surface treatments on yttria-tetragonal zirconia polycrystal (Y-TZP) characteristics and on resin-mediated zirconia bond.

Methods: Y-TZP slabs were grit blasted with 45μm alumina or with 30μm silica-coated alumina particles. The chemical treatments were: no-chemical treatment (NC), silane-containing primer (SP), MDP (10-Methacryloyloxydecyl dihydrogen phosphate) and silane-containing primer (MPS), MDP-containing primer (MP) and MDP and silane-containing adhesive (MPA).

In Vivo Measurement of Root Canal Wall Temperature at Different Stages Prior to Fiber Post Cementation.

Objective: This study measured the in vivo temperature of prepared root canal walls during various stages of treatment prior to endodontic postcementation.

Materials And Methods: One tooth each from five patients requiring endodontic treatment received conventional gutta-percha obturation. The coronal 4 mm of gutta-percha was removed by drilling and the canal wall temperature was measured.

Comparison of in vivo and in vitro models to evaluate pulp temperature rise during exposure to a Polywave® LED light curing unit.

Objectives: To measure and compare in vivo and in vitro pulp temperature (PT) increase (ΔTEMP) over baseline, physiologic temperature using the same intact upper premolars exposed to the same Polywave® LED curing light.

Methodology: After local Ethics Committee approval (#255,945), local anesthesia, rubber dam isolation, small occlusal preparations/minute pulp exposure (n=15) were performed in teeth requiring extraction for orthodontic reasons. A sterile probe of a temperature measurement system (Temperature Data Acquisition, Physitemp) was placed within the pulp chamber and the buccal surface was sequentially exposed to a LED LCU (Bluephase 20i, Ivoclar Vivadent) using the following exposure modes: 10-s low or high, 5-s Turbo, and 60-s high.

Physicochemical and morphological characterization of a glass ceramic treated with different ceramic primers and post-silanization protocols.

Objective: Evaluate the effect of different ceramic primers and post-silanization protocols on physicochemical and morphological characteristics of a lithium disilicate glass ceramic.

Methods: Lithium disilicate ceramic (IPS e-max CAD) plaques (6 × 10 × 2 mm) were divided into 3 groups according to the ceramic primer used: (1) Silane (RelyX Ceramic Primer-RL); (2) Silane + MDP (Clearfil Ceramic Primer Plus-CP); (3) Self-etching ceramic primer (Monobond Etch and Prime-MB). Specimens from each group were distributed into 5 sub-groups according to post-silanization protocols: (a) Treated as recommended by the manufacturer (MR), (b) MR + Additional drying with air at room temperature for 30 s (RTA), (c) MR + additional drying with hot air for 30 s (HT), (d) MR + Surface rinsing with water at room temperature for 10 s and drying with air at room temperature for 30 s (WT), and (e) Specimens were not silanized (NS).

Bonding effectiveness of tooth-colored materials to resin cement provided by self-etching silane primer after short- and long-term storage.

Statement Of Problem: Glass-ceramic materials are typically treated with hydrofluoric acid (HF) and silane to improve their bond to composite resin; however, HF may be harmful to human tissues and the integrity of the material, and its application is a technique-sensitive procedure. A novel self-etching ceramic primer has been introduced with the claim that it can solve those problems. However, independent scientific evidence regarding its performance is scarce.

Effect of light absence or attenuation on biaxial flexural strength of dual-polymerized resin cements after short- and long-term storage.

Objective: To evaluate whether biaxial flexural strength (BFS) of dual resin cements is affected by light absence or attenuation, storage time, or cements' chemical nature.

Materials And Methods: One hundred and twenty disk-shaped specimens were made from each cement (non-self-adhesive cement and self-adhesive cement) using Teflon molds on a controlled temperature surface (35°C). Specimens were polymerized as follows (N = 30): self-cured, directly light-cured, light-cured at a distance of 6 mm between the light tip and the specimen, and through a 6-mm thick composite resin barrier (indirectly light-cured).

Depth of cure of bulk fill resin composites: A systematic review.

Objective: To evaluate scientific evidence regarding depth of cure of bulk-fill resin composites (BFRCs) and related factors.

Material And Methods: PubMed/Medline, Embase, Scopus, and ISI Web of Science databases were accessed from October 2016 to May 2017. Investigations published in English language, assessing depth of cure of BFRCs by microhardness test and/or degree of conversion (DC) were included.

Cracked tooth syndrome in irradiated patients with head and neck cancer.

Objectives: The aim of this study was to assess the presence of enamel craze lines (ECLs), part of the spectrum of the so-called cracked tooth syndrome, on the surface of teeth irradiated in vivo.

Study Design: Forty teeth extracted from patients with head and neck cancer were paired, matched, and equally divided into 4 groups: noncarious irradiated (G1); noncarious control (G2); radiation-related caries (RRC) (G3), and carious control (G4). Samples were examined for ECL detection with a fiberoptic transillumination device and photographed, and ECL mean size, number, and patterns of topographic distribution in tooth crown were determined.

Effect of acid etching on tridimensional microstructure of etchable CAD/CAM materials.

Objective: Evaluate if etching protocols affect superficial/internal microstructural integrity of CAD/CAM ceramic materials.

Methods: Sixty blocks (3×3×3mm) of IPS/Empress-LEU, IPS/e.max-LDC (Ivoclar-Vivadent) and Enamic-PIC (VITA) were used.

Impact of head and neck radiotherapy on the mechanical behavior of composite resins and adhesive systems: A systematic review.

Objectives: To analyze the evidence regarding the impact of head and neck radiotherapy (HNRT) on the mechanical behavior of composite resins and adhesive systems.

Methods: Searches were conducted on PubMed, Embase, Scopus and ISI Web of Science databases using "Radiotherapy", "Composite resins" and "Adhesive systems" as keywords. Selected studies were written in English and assessed the mechanical behavior of composite resins and/or adhesive systems when bonding procedure was conducted before and/or after a maximum radiation dose ≥50Gy, applied under in vitro or in vivo conditions.

Head and neck radiotherapy does not increase gelatinase (metalloproteinase-2 and -9) expression or activity in teeth irradiated in vivo.

Objective: Recent studies suggested that head and neck radiotherapy increases active forms of matrix metalloproteinases (MMPs) in the dentin-enamel junction (DEJ), leading to enamel delamination and radiation-related caries. This study aimed to assess the expression and activity of the gelatinases MMP-2 and MMP-9 in the DEJ and dentin-pulp complex tissues of teeth irradiated in vivo.

Study Design: Thirty-six teeth were studied, including 19 irradiated and 17 non-irradiated controls.

Postradiation Matrix Metalloproteinase-20 Expression and Its Impact on Dental Micromorphology and Radiation-Related Caries.

Recent evidence suggests that head-and-neck radiotherapy (HNRT) increases active forms of matrix metalloproteinase-20 (MMP-20) in human tooth crowns, degrading the dentin-enamel junction (DEJ) and leading to enamel delamination, which is a pivotal step in the formation of radiation-related caries (RRC). Additional participation of enzymatic degradation of organic matrix components in caries progression was attributed to MMP-20 in dentin. Therefore, the current study tested the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes to the enamel and dentin.

Structural Analysis of Enamel in Teeth from Head-and-Neck Cancer Patients Who Underwent Radiotherapy.

Objective: To analyze macroscopic, microscopic, and ultrastructural aspects of enamel from head-and-neck cancer patients submitted to radiotherapy.

Materials And Methods: Twenty sound extracted permanent molars were used and divided into 2 groups. The experimental group consisted of 10 molars from head-and-neck cancer patients submitted to radiotherapy with total doses that ranged from 50 to 70 Gy.