Home-Based Respiratory Physiotherapy and Telephone-Based Psychological Support for COVID-19 Survivors in Peru: Protocol for a Randomized Controlled Trial.

BACKGROUND: Both pulmonary and mental health are affected following hospitalization for COVID-19 pneumonia. Pulmonary rehabilitation therapy has demonstrated benefits in improving mental health, but no validated combined programs that include mental health have been proposed. OBJECTIVE: This article presents the design of a trial that aimed to assess whether the participation in a combined rehabilitation program that includes home-based respiratory physiotherapy and telephone-based psychological support is associated with a greater improvement of pulmonary and mental health outcomes 7-12 weeks after COVID-19 hospitalization discharge compared with posthospital usual care provided by a public Peruvian hospital. METHODS: WAYRA (the word for air in the Quechua language) was an open-label, unblinded, two-arm randomized controlled trial. We recruited 108 participants aged 18-75 years who were discharged from the hospital after COVID-19 pneumonia that required >6 liters/minute of supplemental oxygen during treatment. Participants were randomly assigned at a 1:1 ratio to receive the combined rehabilitation program or usual posthospital care provided by a public Peruvian hospital. The intervention consisted of 12 at-home respiratory rehabilitation sessions and 6 telephone-based psychological sessions. The primary outcome was the 6-minute walk distance. Secondary outcomes included lung function, mental health status (depression, anxiety, and trauma), and quality of life. Outcomes were assessed at baseline (before randomization) and at 7 and 12 weeks after hospital discharge to assess the difference between arms. RESULTS: This study was funded by the Peruvian National Council of Science Technology and Technology Innovation in July 2020. Ethics approval was obtained on September 2, 2020. Recruitment and data collection occurred between October 2020 and June 2021. Results are expected to be published by the end of 2022. CONCLUSIONS: WAYRA was the first randomized controlled trial evaluating combined pulmonary-mental health rehabilitation for hospitalized COVID-19 survivors in resource-limited settings, potentially providing a foundation for the cost-effective scale-up of similar multidisciplinary rehabilitation programs. TRIAL REGISTRATION: ClinicalTrials.gov NCT04649736; https://clinicaltrials.gov/ct2/show/NCT04649736. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/36001.

Shear bond strengths of 2 intraoral porcelain repair systems to porcelain or metal substrates.

STATEMENT OF PROBLEM: When clinical fractures of the ceramic veneer on ceramometal can be repaired, the need for remake can be eliminated or postponed. A number of ceramic repair materials are available; bond strength data would be useful for predicting the success of a given repair system. PURPOSE: This in vitro study evaluated shear bond strengths of 2 porcelain repair systems intended for intraoral bonding of resin to porcelain and metal. MATERIAL AND METHODS: Sixty cylindrical specimens were fabricated with feldspathic porcelain and/or a high noble alloy: 20 porcelain (P), 20 porcelain and metal (PM), and 20 metal (M). Specimens were divided into subgroups of 10, and resin composite cylinders were bonded with 1 of 2 systems: CoJet-System (CJ) or Ceramic Repair (CR). Bonded specimens were stored in 37 degrees C distilled water for 24 hours before being thermocycled at 5 degrees C to 55 degrees C for 300 cycles with a 30-second dwell time. The specimens then were stored for an additional 8 days before being subjected to shear force in a universal testing machine at a crosshead speed of 5 mm/min. Stress at failure was calculated in MPa, and mode of failure was recorded. Analysis of variance (ANOVA) was applied to the data. Comparisons between substrates were made with the Duncan multiple range test (P <.05), and differences between the 2 repair systems within like substrate groups were examined with the Student t test. RESULTS: Bonding groups exhibited the following values in megapascals: PM-CR = 19.3 +/- 4.1; PM-CJ = 25.0 +/- 3.1; M-CR = 14.3 +/- 4.9; M-CJ = 23.0 +/- 2.3; P-CR = 18.3 +/- 4.2; P-CJ = 22.4 +/- 5.6. The ANOVA results showed significant differences between the CJ and CR groups. The Student t test revealed that the mean data for the CJ groups were significantly higher than for the CR groups (P <.05). The Duncan multiple range test demonstrated significant differences between the PM and M groups (P <.05) for the CR system only. CONCLUSION: Under the conditions of this study, CJ achieved significantly higher bond strengths to PM and M substrates. Significant differences in strength were found between PM and M, but only within the CR system.

Clinical assessment of high-strength all-ceramic crowns.

STATEMENT OF PROBLEM: All-ceramic crowns are being used extensively. Little data are available on their clinical performance. PURPOSE: This study evaluated the clinical performance of In-Ceram (Vita Zahnfabrik) crowns. MATERIAL AND METHODS: Forty-one patients (16 men, 25 women; mean age 47.3 years, range 18 to 77 years) were examined with a total of 80 In-Ceram all-ceramic crowns fabricated at the University of Iowa College of Dentistry from 1994 to 1997. The percentage distribution for crowns included: 67% anterior single crowns, 26% posterior single crowns, 6% anterior implant crowns, and 1% posterior implant crowns. This study documented the integrity of the junction between crown and tooth, color match to adjacent teeth, secondary dental caries, wear of crown and opposing dentition, and visible cracks in the crown. Alpha, Bravo, and Charlie ratings were assigned with a modified USPHS criteria. The patients were also surveyed with respect to oral hygiene and satisfaction of treatment. Estimations of 4-year success rates and corresponding confidence intervals were calculated by fitting a constant hazard function model with the SAS procedure GENMOD. RESULTS: Marginal integrity for 88% of artificial crowns was rated Alpha or Bravo. Shade match for 99% was Bravo or better. Only 1% of the crowns were carious, and 1 crown exhibited occlusal wear. One premolar crown had a small fracture of veneering porcelain. One molar crown was remade after core fracture. All patients (100%) expressed satisfaction with their crowns. The estimated 4-year success rates (Alpha or Bravo), with 95% confidence intervals in parentheses were calculated as: 83.5% (65.7%-94.6%) for marginal integrity, 95.8% (82.9%-99.8%) for shade match, and 95.5% (81.6%-99.7%) for secondary caries, 100% (88%-100%) for wear, and 100% (88%-100%) for cracks.

Microhardness of provisional fixed prosthodontic materials.

STATEMENT OF PROBLEM: Provisional restorations play a critical role in the success of restorative treatment. Thus, the provisional restoration must maintain its surface integrity throughout the restorative process. PURPOSE: This study evaluated the microhardness of 5 prosthodontic provisional materials. MATERIAL AND METHODS: Cylindrical samples of 3 bis-acryl resin composites (Integrity, Protemp Garant, Temphase) and 2 methyl methacrylate acrylic resins (Jet, Temporary Bridge) were fabricated (n = 5 per material). Specimens were wet-sanded through 600 grit abrasive and stored in artificial saliva at 37 degrees C for a total of 14 days. Baseline Knoop hardness (KHN) was measured 24 hours after specimen fabrication. Three microhardness measurements were obtained from each specimen. Knoop hardness was again recorded after 14 days of storage. RESULTS: ANOVA and Duncan's tests (P<.05) indicated a significant difference between the methyl methacrylate type resins and the bis-acryl resin composites at both time intervals. CONCLUSION: The hardness of most materials (Integrity, Protemp Garant, Jet) decreased over time. All of the bis-acryl resin composite materials exhibited superior microhardness over traditional methyl methacrylate (Jet, Temporary Bridge) resins.

Colorimetric assessment of laser and home bleaching techniques.

PURPOSE: This study recorded in vitro color change of three tooth bleaching techniques that included laser-activated hydrogen peroxide and two concentrations of carbamide peroxide. MATERIALS AND METHODS: Forty extracted human central incisors were exposed to argon laser-activated 35% H2O2, 10% carbamide peroxide, or 20% carbamide peroxide. A fourth group (control) did not receive any bleach treatment (n = 10/group). Commission International de l'Eclariage (CIE) L*a*b* coordinates were recorded prior to bleaching (baseline), at 1 week, and at 2 weeks. The color difference (delta E*ab) between baseline and subsequent measurements was calculated. RESULTS: The control group did not demonstrate significant color difference over time (p > .05). The laser group was not statistically different from the control group (p > .01). The color difference of the 10% and 20% carbamide peroxide groups was statistically different from the control group (p < .01). CLINICAL SIGNIFICANCE: Exposure to 20% carbamide peroxide produced the greatest perceivable change in color. The recommended one-time application of laser-activated hydrogen peroxide did not demonstrate any perceivable color change. The clinician should be aware that additional or longer applications may be required.

Current status of luting agents for fixed prosthodontics.

STATEMENT OF THE PROBLEM: The long-term clinical outcome of fixed prosthodontic treatment depends, in part, on the use of adhesives that can provide an impervious seal between the restoration and the tooth. There are several types of available luting agents, each possessing unique properties and handling characteristics. No one product is ideal for every type of restoration. PURPOSE: The purpose of this article is to review available dental luting agents, discuss improvements and drawbacks in newly formulated adhesives, and present the indications for their use. RESULTS: Each cement type is physically and chemically unique. A single adhesive will not suffice in modern day clinical practice.

Alumni self-perception of competence at time of dental school graduation.

A survey instrument was administered to recent alumni to evaluate self-perceived competency in twenty-one selected areas at the time of graduation. The questionnaire was completed by 439 (62.8 percent) alumni who graduated between the years 1985 and 1994, inclusive. Graduates generally felt most competent in their ability to treat dental caries and its sequelae and least competent in their ability to recognize myofascial pain and temporomandibular joint disorders. Very little association was demonstrated between demographic characteristics of the respondents and their competency self-ratings. The survey identified areas of strengths and weakness within the present comprehensive care curriculum as perceived by the graduating dentists.

Deflection and stress distribution in three different IMZ abutment designs.

PURPOSE: The purpose of this study was to compare the stress distribution in the resin element and the retaining screw for three different IMZ prosthetic systems: 1) original threaded Intra-Mobile Element (IME); 2) Abutment Complete (ABC); and 3) Intra-Mobile Connector (IMC). This stress distribution comparison was then related to variations in deflection of the prosthetic superstructure. MATERIALS AND METHODS: Employing the finite element method, a three-dimensional model simulating a cast gold restoration attached to an osseointegrated IMZ implant fixture was generated for each system. The representation of the implant fixture, the supporting structures, and the external contours of the crown were identical in the three models, while the configuration of the abutment varied to characterize the individual systems. Each model was discretized into axisymmetric finite elements representing the crown, the various implant system components, and supporting structures. A series of harmonic functions was written to define non-axisymmetric loads of 100 N and 500 N evenly distributed over the entire occlusal surface of the crown. Each load was applied individually to the models, first in a vertical direction, and then at a 45 degree angle to the median plane. Predicted deflection and stress distributions were computed and plotted for each loading condition of each model. RESULTS: Deflections measured at the buccal cusp tip ranged from 0.002 mm (100-N load applied vertically to the ABC model) to 0.802 mm (500-N load applied at 45 degrees to the IME model). Maximum effective stresses in the retaining screw ranged from 129 MPa (100-N load applied vertically to the ABC model) to 1,315 MPa (500-N load applied at 45 degrees C to the IMC model). A correlation was observed between the peak stresses in the screw and the deflection of the superstructure. CONCLUSIONS: Deflections and stress concentrations with the IMC were predicted to be in the same range as with the IME, but much greater than with the ABC.

Finite element stress analysis of IMZ abutment designs: development of a model.

PURPOSE: This article describes the development of a model system for use in finite element stress analysis of three different IMZ abutment designs: original threaded Intra-Mobile Element (IME), Abutment Complete (ABC), and Intra-Mobile Connector (IMC). MATERIALS AND METHODS: A three-dimensional model simulating a cast gold crown restoration attached to an osseointegrated IMZ implant fixture was generated for each abutment design. Each model was discretized into axisymmetric finite elements representing the crown, the various implant system components, and supporting structures. A convergence test was performed to optimize the mesh. Convergence test mesh refinement for the IME, the IMC, and the ABC abutment models resulted in 818 elements, 2,566 nodes; 738 elements, 2,362 nodes; and 663 elements, 2,051 nodes, respectively. Progressive tightening of the retaining screw (preload) was simulated; the degree of screw tightening necessary to prevent opening of the crown-abutment interface in extreme loading (500-N occlusal load at 45 degrees) was determined individually for each system. CONCLUSIONS: Models of three IMZ abutment designs have been refined and the appropriate relative screw preloads determined. This model system is to be used subsequently in stress analysis comparison for the three systems.

Panavia/sandblasted resin bonded prostheses: a five year retrospective study.

The authors feel that this study suggests that the Panavia/sandblasted retention method, with its low debond rate, is a viable method for luting resin bonded prostheses. The authors wish to acknowledge the services of Ms. Jane Jakobsen (statistician) and Ms. Connie Norton (secretary) who made significant contributions to the completion of this article. Their help was much appreciated.

Influence of post dimension on stress distribution in dentin.

Stress distribution studies can be helpful in determining the appropriate diameter and length of endodontic posts for specific teeth in select occlusal relationships. This study selected the finite element method to predict distribution of stresses in dentin of an endodontically treated tooth restored with cast post and cores with various post dimensions. Peak dentinal shear stresses occurred adjacent to the post at mid-root. Peak shear stresses were elevated as the length of the post decreased. Peak dentinal tensile stresses occurred in the gingival third of the facial root surface, whereas peak dentinal compressive stresses were evident in the gingival third of the lingual root surface. The distribution of tensile and compressive stresses was not affected with variation in the dimensions of the posts.

Detection of pulpal circulation in vitro by pulse oximetry.

Evaluation of pulse oximetry as a potential method of determining pulp vitality was the subject of this research. An in vitro model of pulpal circulation was fabricated to test the design for a dental pulse oximetry sensor. Blood samples equilibrated with hypoxic gas mixtures were circulated through the model by a peristaltic pump. A pulse was simulated by introduction of gas bubbles into the blood circulation. Pulse oximeter readings for saturation were recorded and compared with blood gas analysis results. Statistical analysis revealed no difference between pulse oximetry and blood gas analysis with a highly significant correlation coefficient. Clinical evaluation of this application is currently in progress.

Optical detection of hemoglobin in pulpal blood.

An in vitro, flow-through optical system was designed to measure hemoglobin (Hb) concentrations in the pulp space. The system included light-emitting diodes and a silicon photodetector positioned on opposing surfaces of human teeth. A syringe pump allowed a controlled flow of blood through the pulp chamber. The Hb concentration was computed as a nonlinear function of transmitted light intensity. Transmitted light intensities were also used as indicators of oxygenation level. Optical measurements correlated with Hb values measured by the conventional cyanmethemoglobin method (r=0.993). The mean percentage error was 5.8%, and the standard error of prediction was 0.77 g/dl for Hb concentrations ranging from 4 to 20 g/dl. Deoxygenated blood exhibited up to 31% lower transmitted intensity. Light transmission through teeth may be useful in the assessment of total Hb and blood oxygenation within the pulp chamber.

Bond strength and surface characterization of a Ni-Cr-Be alloy.

OBJECTIVES: Since resin composite cements adhere directly to base metal surfaces, the composition and integrity of the surface oxide layer is considered critical for adequate bonding. The aims of this study were to determine the tensile bond strength, and assess predominant surface oxides and oxide layer depth on the surface of a Ni-Cr-Be alloy after subjecting the alloy to various surface treatments. METHODS: Cylinders of Ni-Cr-Be (Rexillium III, Jeneric/Pentron) were cast and the following test groups were investigated: Group 0: no furnace oxidation, no air abrasion; Group 1: air fired, starting temperature 650 degrees C, ending temperature 1000 degrees C (1 min hold); Group 2: same firing sequence under vacuum; Group 3: same air firing sequence followed by air abrasion with 50 micrometers Al2O3; Group 4: vacuum fired, air abraded with 50 micrometers Al2O3; Group 5: air fired, air abraded with 280 micrometers Al2O3; Group 6: vacuum fired, air abraded with 280 micrometers Al2O3; Group 7: no furnace oxidation, air abraded with 50 micrometers Al2O3; and Group 8: no furnace oxidation, air abraded with 280 micrometers Al2O3. The oxide composition of three cylinders per group was analyzed with x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Twenty cylinders from each group were bonded together with Panavia 21 (Kuraray), stored in water for 30 d, and tensile tested. Data were analyzed using one-way ANOVA and Duncan's Multiple-Range test (p=0.05). RESULTS: Furnace oxidation brought Be to the surface and increased the oxide thickness. Air abrasion removed the oxide layer and resulted in surfaces containing significant amounts of Al2O3. Bond strengths for Group 0 were significantly lower than bond strengths for Groups 1, 3, 4, 5, 6, 8, but not significantly different from bond strengths for Groups 2 and 7 (p<0.05). SIGNIFICANCE: Results of this study suggest differences in oxide composition and thickness due to various surface treatments. Furnace oxidation did not significantly affect bond strength and may not be required as a separate step for metal preparation if a resin adhesive is used.

Topical fluoride and glass ionomer microhardness.

PURPOSE: To evaluate the effect of topical fluoride gels on the microhardness of three glass ionomer cements. MATERIALS AND METHODS: Cylinders of Ketac-Silver, Photac-Fil, and Fuji II LC were fabricated, stored in distilled water at 37 degrees C for 48 hours, and exposed to a neutral sodium fluoride gel (Karigel-N), and acidulated orthophosphoric acid gel (Karigel), and a stannous fluoride gel (Omni) at 37 degrees C for 36 hours. Knoop hardness was then recorded. RESULTS: Statistical analysis showed significant differences (P<0.01) between groups related to material and treatment Ketac-Silver did not demonstrate significant differences in hardness, whereas exposure to APF decreased the Knoop hardness of Fuji II LC and Photac-Fil.

Short-term fluoride release/uptake of glass ionomer restoratives.

OBJECTIVES: The short-term fluoride release/uptake of four glass ionomer restoratives was measured and compared to the fluoride release after exposure to three commercial fluoride gels. METHODS: Materials tested were: 1) Ketac-Fil (ESPE GmbH); 2) Ketac-Silver (ESPE GmbH); 3) Photac-Fil (ESPE GmbH); and 4) Fuji II LC (GC Corp.). Twenty discs of each material were fabricated and stored in deionized water at 37 degrees C. Initial fluoride release was measured at 24 h intervals for 7 d, and 24 h intervals at the end of each week for 5 wk. After 6 wk, samples were divided into groups and each group was treated for 6 min with one of the following commercial fluoride gels: acidulated phosphate fluoride (APF), neutral sodium fluoride (NaF), and stannous fluoride (SnF2). Control specimens were placed in deionized water. After exposure, fluoride measurements were carried out at 24 h intervals for 7 d, and 24 h intervals at the end of 2 wk. Fluoride exposure was repeated, and measurements were again recorded over 3 wk. RESULTS: Initial fluoride release by all materials was highest during the first 24 h and decreased sharply over the first week. After exposure to APF, fluoride release increased significantly for all materials. Exposure to NaF also resulted in increased fluoride release for all materials although it was not as high as the increase recorded after exposure to APF. Exposure to SnF2 did not result in significant fluoride release by any material. SIGNIFICANCE: The results of this study suggest that certain fluoride gels may replenish fluoride within some glass ionomers and thus prolong their cariostatic potential.

Disinfectant storage media and composite/metal bond strength.

PURPOSE: To evaluate the effect of three disinfection procedures on the tensile bond strength of Panavia resin composite cement. MATERIALS AND METHODS: Alloy cylinders were bonded and stored in: (1) 0.2% chlorhexidine; (2) 2% activated glutaraldehyde; (3) distilled water and sterilized with ethylene oxide; and (4) distilled water. Solutions were monitored for bacterial cultures and pH changes regularly for 90 days after which all samples were tested to tensile failure. RESULTS: ANOVA showed no significant difference between mean group bond strengths. A direct positive correlation was demonstrated between solution pH and bond strengths (r = 0.98). All groups were found to represent effective methods for preventing bacterial growth in storage solutions during long term cement bonding studies.

Optical detection of pulpal blood.

An optical system to assess blood within the pulpal cavity was developed. The system included a light-emitting diode source, human incisor teeth, and a silicon photodiode detector. An automated syringe pump was used to flow bovine blood lengthwise through the teeth. Transmitted light intensities were recorded at a collection frequency of 20 reading/min and apparent absorbance units were calculated. The effects of blood concentration, blood flow rate, and pulp chamber size were investigated. It was found that changes in blood flow rate did not cause significant changes in transmitted light intensity. Increases in blood concentration and pulp chamber size resulted in larger absorbance values. These results suggest that photoplethysmography measurements may be sensitive to the amount of blood in the pulp chamber as it reflects the pulsatile-related expansion and contraction of capillaries within the pulp tissue.

A comparison of the tensile strength of four prosthodontic adhesives.

PURPOSE: This study compared the in vitro tensile bond strength of four prosthodontic adhesives to sandblasted base-metal alloy. MATERIALS AND METHODS: Alloy cylinders were bonded end-to-end with the various adhesives, thermocycled, stored for 28 days, and subjected to a tensile load. RESULTS: Mean tensile bond strengths obtained were: Panvia = 42.3 MPa, Metabond = 31.1 MPa, All-Bond = 28.06 MPa, and F21 = 18.5 MPa. Statistical analysis showed significant differences (P < .05) in mean bond strengths between the adhesive systems. CONCLUSION: Under the conditions of this study, the Panavia system showed the strongest mean tensile bond strengths.