Bond Strength and Adhesion Mechanisms of Novel Bone Adhesives.

Bone adhesives offer distinct advantages over the use of screws to attached internal fixation plates (IFPs). As the chemical composition of bone is similar to dentine, it is possible that the types of monomers used to make dentine adhesives could be utilised to affix IFPs to bone. The ability to attach a bio-resorbable IFP to porcine bone was assessed for the monomer 10-methacryloyloxydecyl dihydrogen phosphate (MDP), used either as a homopolymer or a copolymer with urethane dimethacrylate (MDP + U). Additionally, the addition of a priming step (MDP + U + P) was evaluated. The chemical interactions of the monomers with bone were assessed using XRD and imaged using TEM, revealing the formation of nano-layered structures with the MDP primer, something we believe has not been reported on bone. In a 6-week artificial aging study both MDP + U and MDP + U + P demonstrated adequate shear bond strength to affix bio-resorbable IFPs. The cytotoxicity profiles of the adhesive formulations were determined using indirect and direct contact with MC3T3 cells, with indirect conditions suggesting the MDP + U + P is as cytocompatible as the resorbable IFP. The findings of this study suggest our newly developed adhesive has the potential to be used as a bone adhesive to affix bioresorbable IFPs.

Determination of the mental foramen position in dental radiographs in 18-30 year olds.

OBJECTIVES: To determine the radiographic position and reliability of assessing mental foramen (MF) position in relation to premolar crowns in an 18- to 30-year-old UK-based population. METHODS: Following ethical approval and a power calculation, the position of the MF was recorded in relation to premolar crowns and apices in 100 dental panoramic tomographs. Positions were assessed by three senior clinicians independently, then by consensus. Data were analysed using descriptive statistics, χ(2) and Fleiss' and Cohen's kappa. RESULTS: Reliability data showed only fair to moderate agreement on independent scoring. Substantial to almost perfect agreement was achieved by consensus, demonstrating the most common position for the MF to be between the first and second premolar teeth when using both premolar crowns (51%) and apices (76%) as reference points. There was a significant difference in the position of the foramen between the left and right sides (p < 0.05), with only 62% of cases showing symmetry. CONCLUSIONS: The most common position for the MF is between the first and second premolar teeth; however, anatomical variation is seen. Use of pre-operative radiographs to relate the position of the MF to premolar crowns may not be reliable.

Is mandibular molar buccal infiltration a mental and incisive nerve block? A randomized controlled trial.

INTRODUCTION: The aim of this study was to compare the efficacies of buccal local anesthetic infiltrations at various sites of the mandible in order to elucidate the mechanism of action of articaine mandibular infiltrations. METHODS: After a power calculation and ethical approval, 22 volunteers received 1.8 mL 4% articaine hydrochloride with 1:100,000 adrenaline as a buccal infiltration at the canine, first, or second molar in a randomized, double-blind, crossover design. The injections at the canine and first molar were considered equidistant from the mental foramen. Responses of the first and second molars, first premolar, and lateral and central incisors were assessed using an electronic pulp tester over a 47-minute period. Volunteers were asked to rate the discomfort of each injection using a visual analog scale. Data were analyzed using repeated measures analysis, McNemar, and Mann-Whitney U testing. RESULTS: Injections at the canine and first molar teeth produced anesthesia in all teeth tested in some volunteers. There was no significant difference between anesthetic success of the first premolar after infiltration at the canine or the first molar. Injection at the second molar failed to produce anesthesia of the incisor teeth. Anesthesia was significantly more likely after injections at an adjacent site. There was no difference in discomfort associated with injections at different sites of the mandible. CONCLUSIONS: Articaine first mandibular molar infiltrations achieve an effect via a combination of modified mental and incisive nerve block and local infiltration. Infiltration at the second molar produces anesthesia of both molar and premolar teeth, primarily via infiltration.

A comparison of the anterior middle superior alveolar nerve block and infraorbital nerve block for anesthesia of maxillary anterior teeth.

BACKGROUND: The authors conducted a study to compare the efficacy of the anterior middle superior alveolar (AMSA) nerve block with that of the infra-orbital nerve block (IONB) in achieving pulpal anesthesia in the anterior maxilla. METHODS: Twenty-eight healthy adult volunteers received 1.0 milliliter of 2 percent lidocaine with 1:80,000 epinephrine as an AMSA nerve block or IONB via computer-controlled local anesthetic delivery (CCLAD) across two visits. The authors used electronic pulp testing to measure pulpal anesthesia. Participants provided subjective reports of lip numbness and injection discomfort. The authors analyzed the data by using the McNemar, Mann-Whitney and t tests. RESULTS: Anesthetic success, defined as two or more consecutive episodes of no sensation in response to maximal stimulation, was significantly greater with the AMSA nerve block than with the IONB in central (P = .012) and lateral (P < .001) incisors; however, anesthesia was achieved in only 42.9 percent of central incisors with the AMSA nerve block. The authors observed a significantly greater number of episodes of no response in the premolar and canine teeth after IONB. Onset of anesthesia was shorter after IONB in canines (P = .002) and central incisors (P = .022). The incidence of subjective lip numbness was 100 percent after IONB and 14.3 percent after AMSA nerve block (P < .001), with numbness lasting twice as long after IONB (P = .019). The authors noted no significant difference in injection discomfort between the two techniques (P = .768). CONCLUSIONS: The IONB produced anesthetic success in canine and premolar teeth, with a more rapid onset than that for the AMSA nerve block. Although the AMSA technique was significantly more successful than IONB in attaining incisor anesthesia, it was ineffective for central incisors, as assessed according to rigorous electronic pulp testing. The IONB and AMSA nerve block produced similar levels of injection discomfort.

Articaine infiltration for anesthesia of mandibular first molars.

A randomized, controlled trial of 31 healthy volunteers compared 4% articaine with 1:100,000 epinephrine buccal infiltration to buccal plus lingual infiltration of the same dose of drug in achieving pulpal anesthesia of mandibular first molar teeth. Data were compared with efficacy of an inferior alveolar nerve block using 2% lidocaine 1:80,000 epinephrine in a cohort of 27 of the volunteers. Anesthesia was determined using electronic pulp testing. Buccal and buccal plus lingual infiltrations of articaine with epinephrine did not differ in efficacy in obtaining pulpal anesthesia for mandibular permanent first molars (p = 0.17). Efficacy of 4% articaine with epinephrine infiltrations for first molar pulp anesthesia was similar to that of an IANB using lidocaine with epinephrine over a 30-minute study period (96 and 80 episodes of no response to maximal stimulation respectively, p = 0.097). Subjective tooth numbness was more common after IANB than buccal infiltration (p = 0.005). The discomfort of buccal infiltration with articaine was volume dependent (p = 0.017) and similar to that of an IANB.