How improving access times had unforeseen consequences: a case study in a Dutch hospital.

OBJECTIVES: To investigate the consequences of increasing capacity to reduce access times, and to explore how patient waiting times and use of physical capacity were influenced by variability. DESIGN: A retrospective case study that combines both primary and secondary data. Secondary data were retrieved from a hospital database to establish inflow and outflow of patients, utilisation of resources and available capacity, realised access times and the weekly number of new patients seen over 1 year. Primary data consisted of field notes, onsite visits and observations, and semistructured interviews. SETTING: A secondary care facility, that is, a rheumatology department, in a large Dutch hospital. PARTICIPANTS: Analyses are based on secondary patient data from the hospital database, and the responses of the interviews with physicians, nurses and Lean Six Sigma project leaders. RESULTS: The study shows that artificial variability was increased by managerial decisions to add capacity and to allow an increased inflow of new patients. This, in turn, resulted in undesirable and significant fluctuations in access times. We argue that we witnessed a new multiplier effect that typifies the fluctuations. CONCLUSIONS: Adding capacity resources to reduce access times might appear an obvious and effective solution. However, the outcomes were less straightforward than expected, and even led to new artificial variability. The study reveals a phenomenon that is specific to service environments, and especially healthcare, and has detrimental consequences for access times.

Progression of diabetes retinal status within community screening programs and potential implications for screening intervals.

OBJECTIVE: This study aimed to follow the natural progression of retinal changes in patients with diabetes. Such information should inform decisions with regard to the screening intervals for such patients. RESEARCH DESIGN AND METHODS: An observational study was undertaken linking the data from seven diabetes retinal screening programs across the U.K. for retinal grading results between 2005 and 2012. Patients with absent or background retinopathy were followed up for progression to the end points referable retinopathy and treatable retinopathy (proliferative retinopathy). RESULTS: In total, 354,549 patients were observed for up to 4 years during which 16,196 patients progressed to referable retinopathy. Of patients with no retinopathy in either eye for two successive screening episodes at least 12 months apart, the conditions of between 0.3% (95% CI 0.3-0.8%) and 1.3% (1.0-1.6%) of patients progressed to referable retinopathy, and rates of treatable eye disease were <0.3% at 2 years. The corresponding progression rates for patients with bilateral background retinopathy in successive screening episodes were 13-29% and up to 4%, respectively, in the different programs. CONCLUSIONS: It may be possible to stratify patients for risk, according to baseline retinal criteria, into groups with low and high risk of their conditions progressing to proliferative retinopathy. Screening intervals for such diverse groups of patients could safely be modified according to their risk.

Retrofitting a crown to a sleep apnea device by using computer-aided design and computer-aided milling technology.

Retrofitting a new crown to an existing dental device is challenging. The continued evolution of computer-aided design and computer-aided manufacturing (CAD/CAM) significantly simplifies the process. This article demonstrates retrofitting a gold crown to an existing sleep apnea device.

Considerations for ceramic inlays in posterior teeth: a review.

This review of ceramic inlays in posterior teeth includes a review of the history of ceramic restorations, followed by common indications and contraindications for their use. A discussion on the potential for tooth wear is followed by a review of recommended preparation design considerations, fabrication methods, and material choices. Despite the improved materials available for fabrication of porcelain inlays, fracture remains a primary mode of inlay failure. Therefore, a brief discussion on strengthening methods for ceramics is included. The review concludes with a section on luting considerations, and offers the clinician specific recommendations for luting procedures. In conclusion, inlay success rates and longevity, as reported in the literature, are summarized.

Survival rates of all-ceramic systems differ by clinical indication and fabrication method.

SELECTION CRITERIA: Approximately 50 articles were included in this review based on a MEDLINE and PubMed search of English-language peer-reviewed literature focused on research published between 1993 and 2008. The authors also hand searched relevant dental journals. Randomized controlled trials, nonrandomized controlled trials, longitudinal experimental clinical studies, longitudinal prospective studies, and longitudinal retrospective studies were all eligible for inclusion in this review. KEY STUDY FACTOR: Treatment of teeth with an all-ceramic restoration in the form of a veneer, inlay, onlay, crown, or fixed dental prosthesis, and the subsequent clinical success or failure of these restorations. MAIN OUTCOME MEASURE: Restoration survival rate (in percent) as a function of observation period and fabrication method, reported by restoration type. Specific fabrication methods for single-tooth restorations included InCeram Alumina, InCeram Spinell, Procera, IPS Empress, IPS Empress 2, and Dicor crowns. Fabrication methods for fixed partial dentures included InCeram, InCeram Zr, IPS Empress 2, and Cercon Zr, respectively. The reported Kaplan-Meier survival rates were grouped by restoration type rather than by ceramic system. MAIN RESULTS: For porcelain veneers, less than 5% failure was reported at 5 years and less than 10% failure rate at 10 years (n ranging from 83 to 3047). For ceramic inlay and onlay restorations, 10-year failure rates were found to be less than 10% (n ranging from 200 to 1588). Greater success rates were reported for anterior crowns. Kaplan-Meier survival rates were calculated for end points ranging in duration from 1 to 4 years (6 studies), 5 to 6 years (12 studies), 7 to 8 years (5 studies), and 10 years or more (2 studies). The results for multiunit prostheses included 11 studies, fewer prostheses, and generally higher failure rates. As with single crowns, failure rates for multiunit prostheses were reported to be consistently higher in the posterior region than anteriorly. Kaplan-Meier survival rates were reported for 3-unit fixed partial dentures for end points ranging from 1 to 10 years, with a mean end point of approximately 5.6 years. CONCLUSIONS: The authors suggest that many all-ceramic restorations were found to demonstrate acceptable longevity compared with conventional restorations (eg, metal-ceramic crowns). For single-rooted anterior teeth, broad support was found for the premise that clinicians may select from any all-ceramic system for laminate veneers, intracoronal restorations such as inlays and onlays, and for full-coverage restorations. For restoration of molar teeth, the review suggests that relatively few all-ceramic systems will provide predictable long-term success. The number of clinical complications with all-ceramic fixed dental prostheses (multiunit) remains high, even with increased connector size. Although zirconium systems offer the advantage of favorable material characteristics for substructures, the clinical problem of chipping of the weaker esthetic veneer persists.

Dentists' molar restoration choices and longevity: a web-based survey.

STATEMENT OF PROBLEM: The increasing trend toward esthetics has led to controversy as to the longevity of esthetic restorations and the wisdom of having traditional restorations replaced for esthetic reasons. With the assumption that the way dentists treat their own teeth may be a good indication of the accumulated wisdom of the profession, knowledge of dentists' own restorative choices may provide guidance in selecting the most appropriate restorations. PURPOSE: The purpose of this article was to determine restorative choices of dentists for personal molars and estimate restoration longevity. MATERIAL AND METHODS: Information about dentists' molars was obtained from a Web-based survey designed to receive dentists' demographic data and charting of 8 molar teeth with estimated longevity. Approximately 12,000 e-mails asking to access the website were sent to dentists' addresses randomly selected from a commercial database. Nonrespondents received 1 reminder. The responses were statistically analyzed with a chi-square analysis (alpha=.05). RESULTS: Seven hundred fifty-seven valid replies provided information for 6,034 teeth (22% unrestored, 75% restored, 2% missing). Restorations reported included amalgam (36%), gold inlay/onlay (13%), complete veneer crown (CVC) (10%), metal-ceramic crown (MCC) (8%), and composite (7%). Other esthetic options accounted for less than 3%. Restorations with more than 20 years longevity included amalgam restorations (58%), gold inlays/onlays (48%) and crowns (23%). Fifty-six percent of esthetic restorations and 5% of amalgams were placed in the last 5 years. The following restorations were placed in the last year (n=186): 38% esthetic, 29% crowns (18% MCC; 11% CVC), and 17% gold inlay/onlay or amalgam. Significant differences (P<.001) were identified for dentist's gender, year of graduation and practice location. CONCLUSIONS: Most dentists have not replaced traditional metallic restorations with esthetic alternatives. Dentists still choose nonesthetic options for significant numbers of their own restorations.

Anterior deprogramming device fabrication using a thermoplastic material.

This article presents a simple and efficient technique to fabricate an anterior deprogramming device using a thermoplastic material. The material, softened by heating, is adapted to the maxillary incisors while moldable. The operator guides the mandible into closure as the material stiffens. The device is then trimmed, and a posterior centric relation record is made using the recording material of choice.

Effect of two types of latex gloves and surfactants on polymerization inhibition of three polyvinylsiloxane impression materials.

STATEMENT OF PROBLEM: Polymerization inhibition of polyvinylsiloxane impression materials has been reported when in sustained contact with some types of latex gloves. PURPOSE: This study examined the polymerization inhibition of 3 polyvinylsiloxane impression materials placed in contact with surfaces subjected to prior contact with gloves or commonly used surfactants. MATERIAL AND METHODS: A 2 x 3 x 4 x 2 design was used (n = 20), with 2 types of gloves (powdered and unpowdered), 3 types of polyvinylsiloxane impression materials (Aquasil, Extrude, and Affinis), 4 surfactant conditions (water, soap/water-rinse, alcohol, and unexposed), and 2 ambient temperatures of 22 degrees C and 36 degrees C. After glove exposure to surfactants, a glass surface was subjected to rubbing contact with the treated glove for a standardized time. After drying, automixed polyvinylsiloxane impression materials were dispensed onto the treated surface. Specimens were removed and evaluated for polymerization inhibition at the manufacturer's recommended polymerization time (36 degrees C), or after 15 minutes at 22 degrees C. Specimens were rated as polymerized, or as inhibited if any polyvinylsiloxane residue remained on the slab. A chi-square analysis was used to evaluate the results (alpha=.05). RESULTS: Setting inhibition was found only with one of the polyvinylsiloxane materials when alcohol was used as a surfactant. At 22 degrees C, the inhibition rate ranged from 95% to 100% for both glove types; at 36 degrees C inhibition ranged from 40% (unpowdered gloves) to 75% (powdered gloves), respectively. CONCLUSION: Under these in vitro conditions, glove exposure to alcohol resulted in polymerization inhibition of 1 of 3 tested polyvinylsiloxane impression materials (Extrude).

Antidepressant use in psychiatry and medicine: importance for dental practice.

BACKGROUND: Many dental patients receive antidepressant therapy. However, antidepressants taken with other drugs may increase the risk of complications that require special dental precautions and care. METHODS: The authors conducted a retrospective study of 1,800 randomly selected patient records and evaluated the prevalence of using antidepressants and other medications concurrently. They analyzed antidepressant intake relative to drug classification and mechanism of action, age, sex and associated potential for clinical complications such as xerostomia, orthostatic hypotension and interaction with vasoconstrictors. The potential for additive adverse effects between antidepressants and other medications also was analyzed. RESULTS: Three hundred eighty-one (21 percent) of the 1,800 patient records indicated that patients were being treated with 412 antidepressants. Female subjects out-numbered male subjects by an approximate 2.3:1 ratio. Selective serotonin reuptake inhibitors were most commonly prescribed, followed by tricyclic antidepressants, atypical and third-generation antidepressants, and monoamine oxidase inhibitors. Based on reported medication intake, almost 58 percent of subjects in the antidepressant group were receiving treatment with two or more medications that had the potential for producing xerostomia. Two hundred fifty-seven (67 percent) of the 381 records documented intake of an antidepressant or other medication with orthostatic hypotension potential. CONCLUSIONS: Three hundred eighty-one patients reported that they were receiving antidepressant therapy for psychiatric and other medical reasons. Potential adverse effects and interactions with other medications have direct implications for dental treatment. CLINICAL IMPLICATIONS: Patients receiving antidepressant therapy are at risk of developing xerostomia and orthostatic hypotension, as well as experiencing the adverse effects of interaction with vasoconstrictors. Dentists must take appropriate precautions in treating these patients.