Implementation of a laboratory quality assurance program: the Louisville experience

Remakes, or the refabrication of dental prostheses, can occur as a result of inherent inaccuracies in both clinical and laboratory procedures. Because dental schools manage large numbers of predoctoral dental students with limited familiarity and expertise as related to clinical prosthodontic techniques, it is likely these schools will experience an elevated incidence of laboratory remakes and their ramifications. The University of Louisville School of Dentistry, not unlike other dental schools, has experienced remakes associated with both fixed and removable prosthodontic procedures. Limitations in faculty standardization and variable enforcement of established preclinical protocols have been identified as variables associated with the high percentage of remakes documented. The purpose of this study was to introduce the implementation of a new multidepartmental quality assurance program designed to increase consistency and quality in both information provided to commercial dental laboratories and the prostheses returned. The program has shown to be advantageous in terms of cost-effectiveness and treatment outcomes. A statistically significant decrease in remake percentages has been recorded from inception of this program in December 2010 until December 2012. Furthermore, this program has resulted in more consistent communication between the dental school and commercial dental laboratories, among faculty members, and between faculty and students.

The importance of correct diagnosis in complete dentures treatment

A 68 years edentulous female, wearing unsuccessful complete dentures, was treated by making a new set of dentures. The main initial complains were unaesthetic teeth, excessive gums display, speech impairment and severe difficulties in mastication. With the patient's full collaboration and following sound established prosthodontics principles, a successful set of full dentures was provided. The main changes performed with the new set of dentures were: A. Provision of three millimeters interocclusal rest space between the vertical dimension while in occlusion and the vertical dimension of rest. B. The full anterior and premolars maxillary teeth and the incisal's third of the mandibular anterior teeth were displayed when patient was speaking, smiling and laughing. No artificial gums were displayed during any normal facial or oral activities. C. The occlusal plane was established after the selection of the anterior teeth. The plane was made parallel to the ala tragus (Camper's) line.

[The registration of false teeth and the others]

The quality control of false teeth should include the control for designing and processing. The registration of false teeth should emphasize particularly on the qualification of the makers, technology management, quality control and the labeling.

The effect of denture quality attributes on satisfaction and eating difficulties

OBJECTIVES

The development of a measure, with complimentary normative and perceived needs, for the investigation of functional impairment of individual patients and the investigation of the physical causative bases of impairment.

SUBJECTS

A consecutive sample of 119 complete denture (CD) wearers attending a Greek department of prosthetic dentistry took part in the study. All subjects presented with some complaint(s) of their dentures.

METHOD

Functional assessment of dentures (FAD) criteria and structured questionnaires were used covering denture satisfaction (DS) and food difficulties with CDs. The questions used a five-point Likert scale.

RESULTS

The results showed that there were statistically significant associations between satisfaction from dentures and eating specified foods. Statistically significant associations were also found between denture qualities and movement of upper dentures and difficulty eating specified foods, but not with an open question on the difficulty of eating unspecified foods.

CONCLUSIONS

This study successfully validated a suitable model for the combined evaluation of denture quality with clear diagnostic criteria and closed questions on DS and perceived difficulties when eating specified foods. This could predict the need for treatment, monitor the impact of care and provide a feasible measure to meet the need of everyday clinical situations.

Low dietary quality among older adults with self-perceived ill-fitting dentures

OBJECTIVE

To examine dietary quality and nutrient intakes of participants wearing dentures with and without poor fit as determined by questionnaire and dental exam.

DESIGN

Nutrient intakes, Healthy Eating Index (HEI) score, and serum nutrient values were examined among individuals wearing either adequate- or poor-fitting dentures and individuals who had at least 18 teeth.

SUBJECTS/SETTING

Data was collected from 4,820 participants in the Third National Health and Nutrition Examination Survey ages 50 years and older with at least 18 teeth (n=3,207) or those wearing dentures (n=1,613), who responded to a questionnaire about denture fit and had their dentures evaluated by a dentist.

STATISTICAL ANALYSES PERFORMED

Analysis of covariance and multivariate linear regression analyses were used to examine associations between individuals fully dentate, wearing good-or ill-fitting dentures, and nutritional status indicators.

RESULTS

The group with self-perceived ill-fitting dentures compared with the group with natural teeth had significantly lower total HEI (66.5 vs 68.5 P<.002), vegetables (6.3 vs 6.8 P<.01), and variety scores (7.8 vs 8.2 P<.02); lower ascorbic acid (P<.009) and carotene intakes (P<.004). The group with self-perceived good-fitting dentures did not differ significantly from the dentate group. However, both groups wearing dentures had significantly lower serum levels of vitamins C and E, beta carotene, folate, lutein, and lycopene/zeaxanthin compared with the dentate group.

APPLICATIONS/CONCLUSIONS

Dietary quality and intake of certain nutrients was poorer among the group with self-perceived ill-fitting dentures than among those wearing adequate dentures or those with natural teeth. Administering a simple questionnaire to patients about their perceptions of denture fit may be useful in identifying denture wearers at increased risk of dietary inadequacy.

[Simulation of pigmented mucosa in complete dentures: development of an oral pigment index]

In the non-Caucasian population the skin and oral tissues show pigmentation to a variable degree, but much more than in Caucasian. When a person becomes edentulous, the tissues containing oral pigmentation disappear. The patient's ethnic background gives no information to predict the characteristics of individual oral pigmentation; other sources have to be found. The mucosal pigmentation of 106 non-Caucasian, dentate people in Amsterdam and Los Angeles was investigated; a classification-chart of oral pigmentation with six types was designed. This tool makes it possible to help patient, dentist and dental technician to choose an accurate simulation of the contour of oral pigmentation in a denture. It is recommended to document the individual pigmentation before extractions are performed.

Provision of removable denture prosthesis at a university teaching hospital in Kenya

OBJECTIVE

To compile an audit of removable denture prosthesis fabricated for patients attending a teaching clinic.

DESIGN

A retrospective analysis.

SETTING

Division of Prosthetic Dentistry, Faculty of Dental Sciences, University of Nairobi, Nairobi, Kenya.

METHOD

Clinical records of the patients attended to in the prosthetic teaching clinic from 1993 to 1997 inclusive were analysed to extract information regarding the quality of clinical notes and the pattern of provision of prostheses.

RESULTS

A total of 817 patients were provided with dentures of whom 602 were provided with complete upper and lower dentures. Single complete dentures were fabricated for 18 patients and 197 patients had partial dentures fabricated.

CONCLUSION

While the number of prostheses provided may be in conformity with the unit resources, clinical notes were found to have significant omissions for which recommendations have been suggested.

Patient satisfaction and dentist evaluation of dentures in South Africa

Denture satisfaction of 100 indigent South Africans, with a mean age of 70.36 years was assessed. Patient satisfaction was compared with measures of occlusion and stability as determined by a dentist. The mean age of the upper and lower dentures was 20 and 21 years respectively. The quality and function of most of the dentures were regarded by the dentists as poor. Of the 59 per cent upper and 49 per cent lower dentures regarded as satisfactory by the elderly, only 17.5 per cent and 5 per cent respectively were evaluated as having good stability. Sixty-nine per cent of those with complete upper and lower dentures said they could eat with their dentures, while only 11 per cent of this group were rated by the dentist as having good occlusion. There existed a big discrepancy between determinants of patient satisfaction and the dentist's evaluation of good stability and occlusion, indicating that patient satisfaction encompasses qualities other than the measures used by the dentist. Once the threshold of satisfaction was achieved, ill-fitting and looseness of dentures took on lesser importance.

[Prosthesis treatment of nursing home residents. New prosthesis preparation or improvement of existing one?]

From a clinical point of view one should show restraint in preparing new dentures for elderly people. It is advised to improve existing dentures. This research project shows that both treatments in elderly, somatically handicapped, nursing home residents do not diminish their complaints and dissatisfaction. Obviously, they are best served by a problem-centred treatment.

Repeatability of a specially designed intraoral colorimeter

A specially modified Minolta CS-100 colorimeter with a DP-101 data processor was designed for intraoral use. To test the repeatability of the results obtained with this specially modified unit, five porcelain and five acrylic resin denture teeth were mounted in a fixed position in front of a fixed mounted meter. Three L*a*b* readings were taken per tooth and mean values were obtained after calibration as a baseline measurement. The readings were repeated on day 3 without recalibration and on day 8 after recalibration. The same-day repeatability showed delta E values < 0.4 in nine of the 10 samples. The day 3 repeatability showed delta E values < 0.4 in only 2 of the 10 samples. The day 8 results, after recalibration, showed delta E values > 0.4 in all of the samples, with a range of 0.57 to 2.75. In vivo testing was performed on five patients with delta E values that ranged from 1.1 to 32.1.

Impact resistance of highly crosslinked plastic denture teeth

The impact resistance of highly cross-linked plastic denture teeth materials such as SR-Orthosit (R), Crystal-ND (R), and Mitel-OM (R) was investigated and compared to that of conventional denture teeth materials. Dentures with upper second molars were placed on a metal model. The thicknesses of the denture teeth were 1.4, 1.0, and 0.4 mm. An impact force was repeatedly applied to the central fossae of the denture teeth with an impact test machine. Impact resistance was defined as the number of impacts sustained by the tooth material prior to fracture. The results showed that the impact resistance of highly crosslinked plastic teeth decreased with decreasing thickness, but was comparable to that of conventional plastic teeth when the teeth were 1.4 mm thick and supported by denture base resin. It is hypothesized that the layer of PMMA denture base resin beneath the denture teeth functions as a shock absorber during impact.

[The stomatologic polishing machine ShM-03]

Herein is introduced a new machine dedicated to the treatment of the metal dentures, ceramics and hard alloys, which allows the patient's treatment in Stomatological Polyclinics. The design of the major parts of the machine--treatment unit and electronic control unit are described. Herein are described in details operation instructions, interlocks information of the unit that allows to extend the life of the motor and of some other electric circuit devices. The advantages of this new machine compared to the alternative Soviet manufactured unit are marked here. Introduction of this machine into production will help to introduce chromium-Cobalt alloys, ceramics and other materials of the heightened hardness into dental prostheses practice.

Reproducibility of an assessment scale of denture quality

Assessment of denture quality is important in prosthetic research. The aim of this investigation was to determine the intra- and interexaminer reliability of denture quality assessment. Three groups of patients with full maxillary and mandibular dentures and two dentists participated. The patients in group 1 (n = 195) were examined by the two dentists independently, in group 2 (n = 35) twice by one of the dentists and in group 3 (n = 20) twice by the other dentist. A denture quality scale was constructed containing nine variables. The internal consistency (coefficient alpha) of this scale was 0.60. The intra- and interexaminer reliability was between 0.59 and 0.86. For individual items of this scale these values were between 0.22 and 1.00.

[Dental prostheses and dental impressions from a hygienic viewpoint]

Dentures, dental impressions, removable orthodontic appliances and all dental technical devices, which are part of any dental treatment are parts as well of a potential crosscontamination chain in dental treatment. Most of those items do not tolerate heat as a sure sterilization medium. For disinfection, chemical disinfectant solutions may be used as far as they work properly and as they are tolerated by the materials in question. Though, one can report some progress in disinfection of dentures and impressions, there are still questions open depending on safety and/or compatibility of the particular materials. For disinfection of removable dentures chlorine-yielding preparations such as Maranon can be recommended. Peracid preparations, such as Sekusept, Sekusept steril and Dentavon may be useful for disinfection of dental impressions. To do the possible means to reduce the infection risk for all persons involved in the dental treatment, patient, dentist, dental technician and all auxiliary persons. This includes both, active hygiene provisions as sterilization and disinfection, as well as possible passive self protection.

Alloys for crown and bridgework

The requirements of alloys for metal-ceramic crowns and bridgework are examined. The functional requirements and manipulative behaviour and cost of cheaper alternatives to high gold alloys are discussed. All types use--high gold, reduced gold, silver palladium and base metal--appear to function satisfactorily in the mouth. Nickel and beryllium do not appear to be health hazards. Dental laboratory procedures and materials must be chosen to suit the type of alloy employed, although all alloy types appear suitable for crown and bridgework. The cost of alloy must be carefully examined in the context of total cost to the patient, and the use of alternatives to gold alloys in many cases may not warrant the required changes to laboratory procedures, but the saving is real, and can make permanent restorations available to greater proportion of the community.

[Retention of a plastic incisor crown by means of acid etching or by parapulpal screw-retained pins]

According to our in vitro experiments, a combination of caustic acid and the brush technique with peripulpar screw dowels appears to be the method to be recommended for the optimal plastic build up of anterior teeth.

[Liability claims for prosthetic treatment]

Liability claims of 153 patients receiving prosthetic treatment were organized according to damage and were discussed on the basis of the known decisions and judgements of the courts.

[Evaluation and habits of wearing model cast prostheses--results of an inquiry among patients]

An evaluation was made of 1246 questionnaires. A difference could be established between patients wearing prostheses for the first time and patients wearing prostheses over a long period of time. No differences were demonstrable between men and women. Age-related differences could not be determined, the treated jaw did not influence the evaluation, and there was no relationship between the type of prosthesis and the subjective statements given by the patients.

[Preparation and impression in crown and bridge prostheses]

The dental profession is asked to increase its efficiency in fighting oral disease. The means to this end are: Improve working quality in every sector and with many small improvements over the minimal effort. Furthermore the service practice, which means an office which offers thorough prophylaxis, teaches oral hygiene to the patients. This is the other efficient means to reduce disease at its root.

The integration of technical services into dental restorative procedures

A protocol for improved dentist-laboratory relations is presented. The mutual responsibilities and obligations of dentist and technician are outlined. Each step of the procedure is developed and projected at the level of case planning and diagnostic wax-up.

[Geometric-mathematical study on the occlusal interference in calotte articulation]

Calculations of occlusal interferences in calotte articulation are reported. It is shown that magnitudes of error due to the different radii of the given calotte and mounting template utp to +/- 20 mm amount to 0.1 mm at most. On the other hand the occlusal errors due to different angles of incidence of the mounting template may attain a magnitude which prevents incorporation of total prostheses.