Efficacy of Proximal Resin Infiltration on Caries Inhibition: Results from a 3-Year Randomized Controlled Clinical Trial.

This study reports 3-y outcomes of a split-mouth randomized clinical trial. Resin infiltration's capacity to arrest caries lesion progression in noncavitated proximal lesions is affirmed. Forty-two consented young adults, blinded to tooth surface allocation, were treated with resin infiltration on 1 randomly selected surface and concurrently experienced a mock infiltration procedure on another. Both treatments were provided as an adjunct to the currently accepted standard-of-care regimen (periodic prophylaxis and serial fluoride varnish applications) appropriate for the management of high caries risk. Challenging periods of low oral hygiene compliance were expected. The primary outcome measure was 3-y radiographic lesion progression. Blinded investigators evaluated each study surface for lesion progression with a series of images obtained at intervals over the 3-y course of study. Proportions of progressing lesions were compared with McNemar's test. Twenty-nine noncavitated lesion pairs in permanent posterior teeth demonstrating caries penetrating into inner enamel or outer dentin were included in the analyses. No adverse events were reported. Radiographic progression was recorded in 4 of 29 infiltrated lesions (14%) and 14 of 29 control lesions (48%, P < .003). Adjunct resin infiltration demonstrated a high 3-y efficacy of 71% (relative risk reduction). The prevented fraction was 86% for infiltration versus 52% for controls. Resin infiltration was 100% successful in arresting caries progression in inner enamel lesions (E2) and 64% in outer dentin lesions (D1). Supplementary microinvasive resin infiltration is significantly more efficacious in reducing proximal lesion progression than management by standard noninvasive therapy alone. Long-term results may shed light on whether this represents the arrest or delay of the caries disease process (ClinicalTrials.gov NCT01584024).

Primary stability in reversed-anatomy glenoid components.

Reversed-anatomy shoulder replacement is advocated for patients with poor rotator cuff condition, for whom an anatomical reconstruction would provide little or no stability. Modern generations of this concept appear to be performing well in the short-term to midterm clinical follow-up. These designs are almost always non-cemented, requiring a high degree of primary stability to encourage bone on-growth and so to establish long-term fixation. Six different inverse-anatomy glenoid implants, currently on the market and encompassing a broad range of geometrical differences, were compared on the basis of their ability to impart primary stability through the minimization of interface micromotions. Fixing screws were only included in the supero-inferior direction in appropriate implants and were always inclined at the steepest available angle possible during surgery (up to a maximum of 30 degrees). The extent of predicted bony on-growth was, of course, highly dependent on the threshold for interface micromotion. In some instances an additional 30 per cent of the interface was predicted to promote bone on-growth when the threshold was raised from 20 microm to 50 microm. With maximum thresholds of micromotion for bone on-growth set to 30 microm, the Zimmer Anatomical device was found to be the most stable of the series of the six designs tested herein, achieving an additional 3 per cent (by surface area) of bone on-growth above the closest peer product (Biomet Verso). When this threshold was raised to 50 microm, the Biomet Verso design was most stable (3 per cent above the second-most stable design, the Zimmer Anatomical). Peak micromotions were not a good indicator of the predicted area of bone on-growth and could lead to some misinterpretation of the implant's overall performance. All but one of the implants tested herein provided primary stability sufficient to resist motions in excess of 150 microm at the interface.

Minimal-resection arthroplasty to treat meniscal tears with associated condyle lesions: finite element analysis.

An early intervention prosthesis which minimizes the extent of resected healthy bone would be advantageous to patients for whom a total or unicompartmental replacement would sacrifice extensive healthy tissue. In this study the use of a device to treat osteoarthritis localized upon a single condyle of the femur with an associated irreparable meniscal tear is considered. The effects of implant alignment are considered from the standpoint of kinematics and potential for cartilage damage. The results suggest that alterations in implant position influence joint kinematics during stance. Anteroposterior (AP) adjustment of the medial prosthesis minimizes the capability of the knee to rotate internally, placing higher demands on the cruciate ligaments. AP adjustments of the lateral prosthesis induces greater posterior drawback, reducing internal-external rotation. Natural knee kinematics are best reproduced by the medial condyle rather than the lateral condyle. Stress exposure of the cartilage increased with the introduction of the femoral condyle prosthesis, which may progress eventually to osteoarthritis, although the results indicate that the medial condyle device is less likely to lead to cartilage damage than is lateral condyle replacement. This study demonstrates that a minimal-resection femoral condyle device may provide sufficient knee joint function to serve as an interim treatment prior to total or unicompartmental knee arthroplasty.

Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants dimethylmethylphosphonate and diisopropylmethylphosponate.

Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black/ organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m(-3). These values are lower than the EC50 value (where EC50 is the airborne concentration sufficient to induce severe effects in 50% of those exposed for 30 min) for the nerve agents sarin (methylphosphonofluoridic acid, 1-methylethyl ester) and soman (methylphosphonofluoridic acid, 1,2,2-trimethylpropyl ester), which has been established as approximately 0.8 mg m(-3). Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes (including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran) in a laboratory air background. In addition, DMMP at 27 mg m(-3) could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferences, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected.

The use of ceramic orthodontic brackets as rest seats for removable partial dentures.

Ceramic orthodontic brackets were developed for the purpose of esthetics and increased tooth-to-bracket strength. An alternative method of preparing a rest seat on the lingual surface of lower canine teeth without violating the enamel integrity is offered. Ceramic orthodontic brackets were bonded to the lingual surfaces of mandibular canines and shaped into rest seats using diamond burs. Because the rest seats are not cut into the tooth structure, sensitivity and potential caries complications are avoided. The bracket is adhered to the tooth surface with a dimethacrylate bonding material. The brackets are bonded with either a no-mix or a two-part adhesive system. The strength of this bond will easily support the forces of a partial denture framework. The advantage over metal acid-etched retained rests is that this method avoids a time-consuming laboratory step. The greatest advantage over the use of composite resins that are shaped into rest seats is the much higher bond strength. After ceramic brackets were bonded to the lingual surfaces of mandibular canines and shaped into rest seats, an impression was obtained for the fabrication of a conventional partial denture framework.

Mutagenic properties of N-nitrosopeptides in mammalian cell culture assays.

Two N-nitrosopeptides, N-(N-acetyl-L-prolyl)-N-nitrosoglycine and N-(N-acetylvalyl)-N-nitrosoglycine, were investigated for genetic toxicity towards mammalian cells using an established line of Chinese hamster ovary cells (CHO-K1-BH4). Observations were made on three indices of genetic damage, namely chromosome aberrations, sister chromatid exchange and induction of thioguanine-resistant variants. Treatment of cells with either compound resulted in dose-dependent increases in all indices, indicating that both compounds are direct-acting mutagens.

The mutagenic properties of N-nitrosopeptides in the Ames test.

N-(N-Acetyl-L-prolyl)-N-nitrosoglycine (APNG) and N-(N-acetylvalyl)-N-nitrosoglycine (AVNG) are shown to exert mutagenic activity in the Salmonella/mammalian microsome mutagenicity (Ames) test. Positive responses are apparent for base-pair substitution mutation-detecting strains (TA1535, TA100 and TA102) both with and without the addition of S9-mix. It is concluded that both APNG and AVNG are direct-acting mutagens.

Nitrosation of peptides.

The synthesis and characterization of N-(N-acetylprolyl)-N-nitroso-glycine, the first authentic N-nitrosopeptide, is described, and its stability under various conditions is reported. In acidic media, denitrosation and deamination (hydrolysis) occur concurrently, whereas in neutral and alkaline solutions, only deamination occurs. The rates of formation and decomposition of some unprotected N-nitrosopeptides in strong acid are also reported. Conditions for the formation of such compounds in the gastric tract are discussed, together with their potential involvement in human cancer.