The Reproducibility and Applicability of an EFD(®) Dispenser in the Prosthetic Technology of Maxillofacial Prostheses.

A reproducible method of dosing pigments can be beneficial and more efficient in the current colour matching procedure in maxillofacial prosthetics. In this study the reproducibility and applicability for pigment dosing of a commercial available EFD(®) dispenser were tested. The reproducibility of a Performus™ II type EFD(®) dispenser was tested by repeating dosing experiments with a set of eight syringes filled with pigment pastes (Factor 2; Flagstaff, USA). To evaluate conventional colour matching, four conventionally colour matched samples were polymerized and compared to the original ones. To investigate the reproducibility of the dispenser in practice, a fifth recipe was dispensed 10 times and colour differences were evaluated visually and as well calculated from measurements with a colour and translucency meter (CTM, PBSensortechnology bv). All dispensed amounts of pigment pastes showed a coefficient of variation in weight of less than 10 %. Evaluating the reproductions of four skin batches compared to the original batches, a ∆E2000 colour difference of 3-7 was measured. Evaluating ten reproductions of one skin coloured batch made with the dispenser, color difference ∆E2000 values compared to the average L*a*b* values, were less than 2 and no visual colour differences could be estimated. Conform these results, low colour differences could be measured with the CTM, indicating no visually observable consequences. Despite the estimated coefficient of variation, the reproducibility of the EFD(®) dispenser in terms of colour difference ∆E2000 of successive dispensing is applicable for colour reproduction in facial prosthetics. Segregation of the current color pastes in due time needs to be taken into consideration.

Variation in repeated mouth-opening measurements in head and neck cancer patients with and without trismus.

Trismus after head and neck cancer treatment may severely limit mandibular functioning. Interventions aimed at reducing trismus can only be evaluated when the amount of variation associated with these measurements is known. The aim of this study was to analyse the variation in mouth-opening measurements in patients treated for head and neck cancer, with and without trismus. Maximal mouth opening was measured in 120 patients in two sessions of three repeated measurements by one observer. To analyse the influence of interobserver variation on mouth-opening measurements a subgroup of 30 patients was measured by a second observer. The standard deviation of the six measurements per patient was used as the variation in measurements of maximal mouth opening. No significant difference was found in maximal mouth opening in patients with (n=33) or without (n=87) trismus. The interobserver intraclass correlation coefficient (ICC) was 0.98. Intraobserver ICC and intersession ICC reliabilities both were 0.99. The variation in the mean values of the three measurements was only slightly smaller than the variation of the single measurements. Variation in maximal mouth opening in patients with trismus does not differ from variation in maximal mouth opening in patients without trismus. Interobserver variation is limited.

[Dissertations 25 year after date 18. Skin colour and facial prosthesis]. / Proefschriften 25 jaar na dato 18. De kleur van aangezichtsprothesen.

The traditional 'trial and error' methods for skin colour recording are not satisfactory. In 1982 a dissertation was published, titled 'Skin colour and facial prosthetics, a colorimetric study'. The dissertation was concerned with a clinical study of skin colour recording objectively in a random sample of 100 people, using subtraction colorimetry. Subsequently, facial prostheses were fabricated for a group of patients with a facial defect who had to undergo radiotherapy. From the results of the study the 3 following conclusions were drawn. Skin colour recording for producing a facial prosthesis need to be carried as close to the facial defect as possible. Alterations of skin colour are determined by light scattering in the skin as well as skin pigments. In patients with facial defects who have to undergo adjuvant radiotherapy, skin colour alterations are present until on average 13-14 weeks after completion of the radiotherapy and from that time point the skin colour remains rather stable. After publication of the dissertation, other research results demonstrated that light scattering in the skin, a sign of skin translucency, may be determined with a fiberoptic scattering meter (volume reflectometer). Using the fiberoptic scattering meter, a colour formula can be made, which by calculation shows the amount of pigments and scattering objects needed to produce the correct translucency and colour of a facial prosthesis. Currently, a small beam reflectometer is used for this purpose.

Satisfaction with treatment outcome in bilateral cleft lip and palate patients.

The aim of this case-controlled study was to assess satisfaction with facial appearance and function, and health-related quality of life (HRQL) in bilateral cleft lip and palate patients (BCLP). The study sample was composed of adult BCLP subjects and controls matched for age, gender and socioeconomic status. Outcome measures included a self-administered questionnaire evaluating satisfaction with facial appearance, function and HRQL. Bivariate statistics were computed to analyse the association between BCLP status and outcome measures. Forty-three treated adult BCLP patients (mean age 28.2 years, SD 7.8) were compared to 43 controls without clefts (mean age 28.5 years, SD 8.0). Quantitative and qualitative assessment revealed that BCLP patients were significantly less satisfied with the appearance of the upper lip, the nose and nasal breathing. Additionally, satisfaction with facial appearance correlated positively with HRQL. For speech, hearing and drinking, quantitative scores did not differ between BCLP and controls, while qualitative assessment revealed that BCLP patients had considerable problems and concerns with these functions. This study underlines the importance of qualitative assessment of patient satisfaction with treatment outcome to identify individual problems and concerns not revealed by quantitative measures alone.

[Post-academic dental specialties 16. Post-academic specialization in maxillofacial prosthodontics]. / Beroepsdifferentiatie in de tandheelkunde 16. Opleiding tot tandarts-maxillofaciale prothetiek.

Maxillofacial prosthodontics is a specialization in dental health practiced in centers for special dental care in The Netherlands by a limited number of dentists and technicians. The necessary skills, which are largely unique in the field of dentistry, were described in 2001 in a training program by the Dutch Association for Gnathology and Prosthodontics. Multidisciplinary diagnostics, treatment planning, and care delivery are taught in a modular system. A shortage of maxillofacial prosthodontists and maxillofacial technicians calls for a structural training of young colleagues.

[Post-academic dental specialties 17. Implant-retained craniofacial prostheses]. / Beroepsdifferentiatie in de tandheelkunde 17. Implantaatgedragen aangezichtsprothesen.

The surgical and prosthetic aftercare of craniofacial prostheses supported by endosseous implants were registered in patients treated with implant-retained craniofacial prostheses in a university clinic during the last two decades. Aftercare was registered during the period from implant placement until the last follow-up visit. Implant survival rate was 95.2% in non-irradiated and 78.8% in irradiated bone. Discoloration of the silicon material, becoming loose of the acrylic clip carrier from the silicone, rupture of the silicone, and ill-fitting of the prosthesis were main reasons for fabrication of a new craniofacial prosthesis.

[Oligodontia: treatment plan and therapy]. / Oligodontie: Opstelling en uitvoering van behandelplannen.

The aim of this retrospective study was to gain insight in treatment planning and therapy for patients with oligodontia. Records of 58 treated patients with oligodontia were screened using several parameters: gender, year and age of registration, symptoms, case history, treatment plan and therapy. Treatment plans were sorted into the following categories: tooth-supported overdentures, fixed or removable partial dentures and implant-supported restorations. Dependent on the complexity of oligodontia, it is advocated to make a treatment plan before the age of 12 years old and to follow the provided treatment conscientiously until the final prosthetic treatment. After analyzing the 58 treatment plans, the following conclusions could be made: the treatment plan was not in all cases made before the age of 12 years, it was not clear in all cases who was the coordinator of the treatment and dental implants are becoming more and more important in treating patients with oligodontia.

Indications for extra-oral implantology.

In this paper, the general indications for implantology for facial prosthesis in the maxillofacial bones are elaborated. Information from both the literature and our own surgical experience emphasizes that only specific locations of the facial bones and skull are suitable for implant fixtures. Careful indication and surgery are required for patients who were exposed to radiotherapy. The success of maxillofacial rehabilitation depends on multidisciplinary cooperation.

Fixation of auricular prostheses by osseointegrated implants.

Placement of enosseous implants in the temporal bone may overcome the apparent disadvantages of skin adhesives and skinpockets for the fixation of auricular prostheses. The surgical procedure for placement of implants in the temporal bone and the results obtained in eight patients wearing implant-supported auricular prostheses are described. From the results of this study, it is obvious that osseointegrated implants have great advantages compared with skin adhesives and skinpockets to rehabilitate patients suffering from auricular defects. The major achievement of implant-supported auricular prostheses is the patients' increased comfort and confidence wearing these types of prostheses.

Use of the final denture base for the intermaxillary registration in an implant-supported overdenture: technical note.

A method of implant-retained overdenture treatment based on the early use of the final denture base during registration of the maxillomandibular jaw relation is described. Using this stable denture base, an accurate recording of jaw relation and an adequate try-in procedure are facilitated without displacement of the base, especially in the situation of an unfavorable flat edentulous mandibular residual ridge.

Psychosocial effects of implant-retained overdentures.

The aim of this study was to compare implant-retained mandibular overdentures and two conventional treatments for their effects on functional ability (chewing, speaking, etc), patient satisfaction, and quality of life (psychosocial functioning). Assignment of 90 patients was executed by means of a balancing allocation computer program to ensure the pretreatment comparability of the three groups. Twelve months after treatment, the average scores for almost all specific quality-of-life measures had improved significantly in all three groups. On average, all patients experienced fewer restrictions in their social activities and had fewer psychological problems because of their full dentures. No impact on the general quality of life was established. One year after treatment, all three dental treatment modalities had a comparably positive effect on dental health-related quality of life.

The cost of dental implants as compared to that of conventional strategies.

The effectiveness of dental implants is widely studied, especially in terms of their clinical outcomes. However, from the policymaker's point of view, variables other than safety and efficacy, such as the costs and effectiveness of dental implants as compared to other treatment alternatives, are vital in decision making. This paper compares the costs of different treatment strategies in a randomized clinical trial in patients with resorbed mandibles and persistent problems with their conventional dentures: treatment with a mandibular overdenture on permucosal dental implants, an overdenture on a transmandibular implant, new dentures after preprosthetic surgery, and new dentures only. Data were gathered on an individual patient level to gain insight into specific cost episodes. Direct costs were subdivided into labor, material, technique, and overhead. Data concerning these components were gathered during the consecutive treatment phases in the first year. Results show that the resources used to treat a patient with an overdenture supported by a transmandibular implant are seven times those of a complete new set of dentures. Comparison of the cost ratio of an implant-retained overdenture supported by permucosal implants and conventional new prostheses proves less unfavorable: 1:3. New dentures after preprosthetic surgery are almost as expensive as treatment with permucosal implants.

Two-center clinical trial of implant-retained mandibular overdentures versus complete dentures-chewing ability.

This study is a two-center clinical trial with the aim to assess the treatment effects of implant-retained mandibular overdentures versus conventional complete dentures. Treatment had been assigned according to a balanced allocation method. The following criteria were used to enhance the comparability of the treatment groups: age, gender, the edentulous period of the mandible, the number of previously made mandibular dentures, the number of years having worn the present mandibular denture and the symphyseal bone height. 151 patients with severely resorbed mandibles participated in the study, they were treated at two centers. Ninety-one patients received an implant-retained mandibular overdenture (IRO) and 60 patients a conventional complete denture (CD). Since some patients refused the allocated treatment the "Intention To Treat" principle was applied. This implies that patients are evaluated in the originally allocated treatment group regardless of the actual treatment they received. Patient's experiences were evaluated before treatment and 1 yr after insertion of the new dentures. Results before treatment showed that both treatment groups were comparable: they were dissatisfied with their mandibular denture and they could hardly chew tough or hard foods. One year after insertion of the new dentures the IRO-group was satisfied with their mandibular denture, whereas only one third of the CD-group was satisfied. With respect to the chewing ability the IRO-group scored significantly better than the CD-group(P<0.0001).

Mandibular overdentures supported by two or four endosteal implants. A prospective, comparative study.

The aim of this prospective study was to evaluate the effect of the number of implants supporting a mandibular overdenture on the condition of the peri-implant tissues. Sixty edentulous patients (Cawood class V VI) participated in this study. After randomization, thirty patients were treated with an overdenture supported by two IMZ implants (group A) and thirty patients with an overdenture on four IMZ implants (group B). The implants were inserted in the anterior region of the mandible. After three months overdentures were constructed, supported by round bar and clip attachments. A standardized clinical and radiographic evaluation was performed 0, 6 and 12 months after insertion of the denture. One implant was lost (group A) during the healing period. There were no significant differences with regard to any of the studied clinical or radiographic parameters of the peri-implant tissues, neither were significant differences found between the lateral and central implants in group B. None of the patients reported a sensory change in lip or chin region. From this study it is concluded that there seems to be no need to insert more than two endosteal implants to support an overdenture, however, long-term prospective studies are needed to support this notion.

Patient satisfaction with implant-retained mandibular overdentures. A comparison with new complete dentures not retained by implants--a multicentre randomized clinical trial.

OBJECTIVES: The aim of this study was to establish the treatment outcome of full denture treatment with or without implant support, in which the outcome assessment focuses on the patient's subjective evaluation ('denture-satisfaction'). DESIGN: A multicenter randomized clinical trial. SUBJECTS: Thirty-two men and 118 women (mean age 56 +/- 9, range 35-84 years) participated in the study. The mean height of the mandible was 13 +/- 2 mm, measured on a lateral cephalometric radiograph. The patients were randomly assigned to either a group treated with implant-retained mandibular overdentures and a new maxillary denture, or to a control group treated with a new set of complete dentures. MAIN OUTCOME MEASURES: Denture satisfaction was assessed using questionnaires focusing on denture-related complaints and 'a general satisfaction rate'. RESULTS: Based on the baseline data, from the 'denture complaints' questionnaire six interpretable factors could be extracted. One factor did not vary following treatment and was excluded from the outcome analysis. At the 1-year evaluation three out of five factors showed significantly better scores for the group treated with implants than for the control-group. The same was found for the general satisfaction rate. CONCLUSION: For patients with a severely resorbed mandible, overdentures retained by dental implants appear to provide a more satisfactory solution to their denture-related problems.

Dutch consensus on guidelines for superstructures on endosseous implants in the edentulous mandible.

This consensus report has been reached under the authority of the Dutch Society for Oral Implantology and the Dutch Society for Prosthetic Dentistry by a panel of Dutch dentists and prosthodontists (listed above) who are involved in the treatment of patients with oral implants, either via practice or via research. They were commissioned with a task to "formulate guidelines for the prosthetic treatment of edentulous patients receiving oral implants in the mandible".

[Fixation of facial and auricular prosthesis with osseous implants in cranial bone]. / Fixatie van gelaats- en oorschelpprothesen met implantaten in schedelbot.

OBJECTIVE: To evaluate the use of osseointegrated implants to fix facial and auricular prostheses. DESIGN: Retrospective. SETTING: University Hospital Groningen, the Netherlands. METHODS: Thirty patients were treated with Brånemark implants for fixation of auricular (21 patients) and orbital (9 patients) prostheses during May 1988-December 1995. The complications during the procedure, the success rate of the implants, skin reactions around the implants and patient satisfaction were recorded. RESULTS: A total of 97 implants were placed. One implant had to be removed after the healing period because it was loose. No other implants were lost during the follow-up period (mean 36 months; range: 12-91). The skin around the implants sometimes showed a mild reaction which could be adequately treated. In most of the cases no inflammation of the skin was observed. Retention, ease of handling and wearing comfort of the facial prostheses were excellent. CONCLUSION: Fixation of facial and auricular prostheses can be improved by osseointegrated implants resulting in high patient satisfaction.

The incomprehensible success of the implant stabilised overdenture in the edentulous mandible: a literature review on transfer of chewing forces to bone surrounding implants.

The approach of implant stabilised overdentures has become one of the routine treatment modalities for compromised edentulous ridges. The purpose of this literature review is to analyze survival rates of loaded implants, occlusal forces and stress distributions of implant stabilised overdentures in edentulous mandibles and of fixed loaded implants at least over a medium-term period. which is comparable with fixed prostheses. Patients with implant stabilised overdentures and with fixed bridges on implants generate similar occlusal forces. The number of implants under a prosthetic construction seems to have less influence on stress distribution than design of the superstructure and related direction of forces.

Overdentures stabilised by two IMZ implants in the lower jaw--a 5-8 year retrospective study.

Clinical and radiographical parameters were assessed in forty patients with overdentures stabilised by two IMZ implants connected by a bar in the lower jaw in a 5-8 years retrospective study. Results indicated that most patients had healthy peri-implant tissues, the mean pocket probing depth was 3.1 mm and the median periotest value was -4. Three implants were removed after the healing period and replaced by three new implants. One implant was lost after six years. One implant was mobile on palpation. None of the patients showed objective signs of dysaesthesia in the lower lip or chin. The peri-implant bone level of most implants had remained stable after one year of service. The overall success rate was 94% (Albrektsson et al.) and it is therefore concluded that two IMZ implants, connected with a bar in the lower jaw, provide a stable base for long-term support of a mandibular overdenture.

[The making of an overdenture supported by two endosseous implants in the lower jaw]. / Het vervaardigen van een overkappingsprothese op twee permucosale implantaten in de onderkaak.

Due to extreme alveolar resorption many edentulous patients wearing complete dentures suffer from loss of function of the orofacial system. Improvement of oral functions can be obtained by increasing the denture-support, using implants. The construction of a combined implant/mucosal supported lower overdenture will be helpful. A method to construct an overdenture on oral implants is described.