A 5-year longitudinal study of cantilevered fixed partial dentures compared with removable partial dentures in a geriatric population

Prosthesis function and dental conditions were observed for 5 years in 27 elderly patients treated with mandibular cantilevered fixed partial dentures (FPDs) and in 26 elderly patients treated with distal-extension removal partial dentures (RPDs). All patients were treated with a complete upper denture. The patients were assigned randomly into two treatment groups that had the same composition with regard to sex, age, and distribution of teeth. The patients were under supervised oral hygiene and prosthodontic care. Clinical examination of prostheses, masticatory system, periodontal status, and caries was carried out yearly. Oral hygiene was good, and the periodontal status was maintained in both groups. Caries was observed six times more frequently in the RPD group than in the group with fixed restorations, however. Occlusal and functional conditions deteriorated in the RPD group only. Eight of 42 fixed partial dentures (19%) failed; of these, six were recemented with composite resin. Generally the need for dental and prosthetic follow-up treatment was more pronounced in the RPD group than in the FPD group.     

Veterans Administration Cooperative Dental Implant Study--comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part III: Comparisons of masticatory scores between two treatment modalities

Five Veterans Administration Medical Centers participated in a study to determine the comparative influence of fixed partial dentures (FDPs) supported by endosteal blade implants and removable partial dentures (RPDs) on masticatory performance. The study design, methodology, and success rates have been described in Parts I and II. A total of 232 patients received comprehensive dental care, including RPDs for 118 patients and FPDs for 114. Three standardized masticatory tests were made with peanuts and carrots before treatment. These tests were repeated at 16 weeks following RPD or implant insertion and thereafter at 6, 18, 36, and 60 months. At entry, there were no significant differences in performance scores and chewing time and strokes taken to reach the swallowing threshold between the RPD and FPD groups (p greater than 0.05). After treatment completion, FPDs and RPDs significantly improved the masticatory ability of patients with Kennedy class I or class II edentulous conditions (p less than 0.001). The improvements in performance scores for both test foods were slightly better in the RPD group than in the FPD group, although none of the 30 mean differences was significant (p greater than 0.05). After the baseline period to 60 months, only slight changes in performance scores were observed for both groups. RPDs and FPDs were comparable in improving the chewing efficiency of patients with Kennedy class I and class II partially edentulous conditions.     

Veterans Administration Cooperative Dental Implant Study--comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part II: Comparisons of success rates and periodontal health between two treatment modalities

Five Veterans Administration centers have participated in a study to determine whether fixed partial dentures (FPDs) supported by blade implants offer an acceptable substitute for mandibular unilateral or bilateral distal-base extension removable partial dentures (RPDs). The study design and methodology have been described in Part I. A total of 232 patients received comprehensive dental care including RPDs for 118 patients and FPDs for 114. Prespecified criteria determined treatment failures. During the 60-month period, treatment failures occurred in 19 FPD patients and 30 RPD patients. Ten FPD failures occurred before and nine after the FPD insertion. Five RPD failures were caused by abutment tooth loss and 25 for not using the RPD while eating. Life table analysis showed 5-year success rates of 84.2% for the FPD and 74% for the RPD. The 17.9% higher FPD success rate in Kennedy class II patients was both statistically and clinically significant. Excluding the 10 early failures, the 5-year FPD success rate was 91.5%. Of the 170 attempted implants, 26 failed, including 12 before the FPD fabrication. Radiographic assessments by a panel of three judges showed no bone deterioration during baseline to 60 months in 29.6%, slight in 25.4%, moderate in 15.9%, marked in 27%, and severe deterioration in 2.1% of the implant posts.     

Veterans administration cooperative dental impant study—Comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part II: Comparison of success rates and periodontal health between two treatment modalities

Five Veterans Administration centers have participated in a study to determine whether fixed partial dentures (FPDs) supported by blade implants offer an acceptable substitute for mandibular unilateral or bilateral distal-base extension removable partial dentures (RPDs). The study design and methodology have been described in Part I. A total of 232 patients received comprehensive dental care including RPDs for 118 patients and FPDs for 114. Prespecified criteria determined treatment failures. During the 60-month period, treatment failures occurred in 19 FPD patients and 30 RPD patients. Ten FPD failures occurred before and nine after the FPD insertion. Five RPD failures were caused by abutment tooth loss and 25 for not using the RPD while eating. Life table analysis showed 5-year success rates of 84.2% for the FPD and 74% for the RPD. The 17.9% higher FPD success rate in Kennedy class II patients was both statistically and clinically significant. Excluding the 10 early failures, the 5-year FPD success rate war 91.5%. Of the 170 attempted implants, 26 failed, including 12 before the FPD fabrication. Radiographic assessments by a panel of three judges showed no bone deterioration during baseline to 60 months in 29.6%, slight in 25.4%, moderate in 15.9>, marked in 27%, and severe deterioration in 2.1% of the implant posts.     

Masticatory and nutritional aspects on fixed and removable partial dentures

The aim of the present study was to evaluate mastication, food selection and nutritional aspects in two groups of persons restored with fixed (FPD, N=44) and removable (RPD, N=40) partial dentures respectively. The subjects were part of a cohort study of 67–68-year-old men living in Malmö, Sweden. The two groups were very similar regarding social factors and the inclusion criteria were chosen so that the groups were very equal regarding oral factors, apart from the difference in fixed and removable partial dentures. The number of natural teeth, number of replaced teeth and occlusal contacts did not differ significantly between the two groups, nor did the distribution of maxillary and mandibular dentures. A comprehensive examination of several general health factors included a home interview of dietary habits. A clinical examination included a 20-minute oral examination with registration of number of teeth, FPDs, RPDs, and occlusal contacts. It also included masticatory tests: chewing gum colour mixing, chewing gum bolus shaping, and swallowing threshold (number of strokes to the first swallow of an almond). The consumption of hard and soft foods was revealed by the dietary interview as well as the intake of energy and some nutrients. There was a significant difference between the groups regarding the capacity to mix the two-coloured chewing gum, to shape the chewing gum bolus and in the consumption of hard foods. There was no difference in the swallowing threshold and the consumption of soft foods. The intake of energy and nutrients did not differ significantly between the groups. The differences in masticatory capacity found thus seem to have little, if any, effect on the factors of importance for general health. A reasonable explanation for the differences found is that artificial teeth that are well retained, such as FPDs, make more active chewing possible than do removable, and often somewhat loose-fitting partial dentures.     

Long-term analysis of biologic and technical aspects of fixed partial dentures with cantilevers

PURPOSE: The aim of the present clinical study was to analyze the long-term treatment outcome of fixed partial dentures (FPD) with cantilevers. MATERIALS AND METHODS: Ninety-two patients with 115 cantilever FPDs on 239 abutment teeth were examined. Immediately following cementation, radiographs of the abutment teeth were obtained. At the follow-up examination 5 to 16 years after cementation, the abutment teeth were clinically and radiographically evaluated. Besides the assessment of periodontal parameters and vitality testing, the presence of carious lesions of the abutment teeth, loss of retention, fracture of bridgework, and fracture of abutment teeth were also recorded. The Student's t test was used to detect differences between abutment teeth and control teeth with natural crowns as well as over time within the groups. RESULTS: Plaque scores and bleeding on probing were low at both abutment and nonabutment teeth. Mean probing pocket depth and level of the clinical attachment never exceeded 3.0 mm in both groups. The radiographic bone levels at abutments were stable within 3% over the observation period. Of the 120 initially vital abutment teeth, 12 (10%) lost vitality during the observation period; one (1%) of the 119 initially nonvital abutments showed periapical pathology. Development of secondary caries was observed at 8% of the 239 abutment teeth. In total, 8% of the abutment teeth were affected by loss of retention, which made up more than half of all technical problems. Material fractures only occurred occasionally, affecting from 1% to less than 3% of the abutment teeth. Fracture of abutment teeth amounted to 3% and was twice as frequent at abutments adjacent to cantilevers compared to abutments not adjacent to cantilevers. CONCLUSION: The most frequent biologic (caries) and technical complications (loss of retention) made up more than half of all problems recorded. These problems may be at least partially avoided by performing optimal plaque control and by strictly observing the rules for preparation of retentive FPD abutments.     

Precision attachment-retained removable partial dentures. Part 3. General practitioner results up to 2 years

PURPOSE: The aim of this study was to analyze the techniques, production problems, and 2-year results of attachment-retained removable partial denture (RPD) treatment provided by general practitioners in Sweden. MATERIALS AND METHODS: At a major dental laboratory, consecutive cases involving new production of crowns, or of fixed partial dentures (FPDs) and RPDs retained with precision attachments, were studied. Parameters of the dentition, crown or FPD, type and brand of attachment, etc, as well as early satisfaction by dentist and patient, were recorded using specially designed forms at the dental laboratory and questionnaires for the dentists. After 2 years, questionnaires were again sent out to the dentists to record complications and patients' and dentists' opinions of the results. The sample gathered totaled 83 constructions. After 2 years, responses for 57 patients, all of whom had distal-extension RPDs, were received. Most drop-outs in the study were explicable. RESULTS: The most frequently cited reasons for using attachments were esthetics and need for crowning the teeth abutting the RPD. McCollum rigid slide attachment was the predominant brand used (43% of constructions). Dentists and patients were dissatisfied with 6% of the constructions. During the first 2 years, 22 of 57 constructions were complication-free. Seventeen had attachment complications and 9 had serious complications related to the abutment teeth or RPDs. A comparison between these 2 groups revealed that those with complications had every second abutment root-canal treated and a root post, while the group without complications had every fifth abutment root-canal treated. CONCLUSION: There were many technical and biotechnical complications and failures; the exact ratio, however, depended on the definition of "complications" and "failure." The 2-year results also deviated considerably from the dentists' opinions of the early results.     

Veterans Administration Cooperative Dental Implant Study--comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part IV: Comparisons of patient satisfaction between two treatment modalities.

This study compares treatment assessments made by two groups of patients with Kennedy class I or class II mandibular edentulous conditions, who received either a removable partial denture (RPD) (N = 115) or one or two fixed partial dentures (FPDs), each supported distally by a blade implant (N = 113). Two questionnaires were administered, one at 16 weeks after the implant or RPD insertion and at the 6-month interval and the other at 18, 36, and 60 months. Marked functional improvements were perceived by a large majority of patients in both groups after the insertion of prosthesis. At 6 months, a higher percent of patients with RPDs than those with FPDs found it easy to clean their RPDs and experienced chewing discomfort, restriction of food choices, feeling of insecurity with their RPDs, and difficulty with their pronunciation. The exclusion of assessments by 25 RPD patients, whose treatment was judged to be a failure functionally, made the mean differences between the two treatments statistically significant (p less than 0.05) only for ease of cleaning in favor of the RPD and fewer restrictions of food choices in favor of the FPD group. At 60 months, significant differences between the percents of patients with the most favorable responses occurred for perceptions of eating enjoyment, food particles seldom getting under the removable partial denture, and improvement in social life in favor of the FPD treatment and for the ease of cleaning the removable partial denture in favor of the RPD treatment. The results seem to support superiority of the FPD in terms of patient satisfaction, but not enough to favor this type of prosthesis over the RPD without consideration of other pertinent factors.     

Microbiological risk for periodontitis of abutment teeth in patients with removable partial dentures

Summary  Tannerella forsythia , Porphyromonas gingivalis and Treponema denticola are identified as the red complex which exists in high proportions in periodontally diseased patients. The aim of this study was to assess the microbiological risk for periodontitis of abutment teeth in subjects wearing removable partial dentures (RPDs) by measuring the red complex using BANA-ZymeTM test. Thirty-eight subjects (mean age: 62·2 years) with Kennedy Class II partially edentulous arch participated in this study. The red complex and clinical parameters, such as plaque index, gingival index, probing depth and tooth mobility were recorded at abutment teeth in contact with the direct retainer of unilaterally designed RPDs and the corresponding non-abutment teeth on the opposite side. Mean scores for the red complex, plaque index, gingival index and tooth mobility of the abutment teeth were significantly greater than those of the non-abutment teeth ( P  < 0·01). No significant mean difference in pocket depth was found between the abutment and non-abutment teeth. Logistic regression analysis revealed that abutment teeth, high scores of plaque index and a maintenance interval longer than 6 months were significant predictors for positive red complex scores ( P  < 0·05). These results suggest that the microbiological risk for periodontitis of abutment teeth is greater than that for non-abutment teeth in RPD wearers.     

老年人可摘局部义齿修复对基牙的影响

目的:分析研究老年人可摘局部义齿修复后对基牙的影响,探讨其原因及预防措施。方法:对95例牙列缺失后的老年人行冷弯卡环固位式可摘局部义齿修复,记录和比较戴可摘局部义齿后基牙和非基牙的龋坏率和缺失率,用χ2检验分析其结果有无差异,并对影响基牙的原因进行分析。结果:戴用可摘局部义齿5a后,基牙的患龋率(17.38%)显著高于非基牙(7.10%);因牙折、牙周病松动及龋坏无法保留而拔除的基牙缺失率(27.01%)也显著高于非基牙(7.79%)(P<0.01)。结论:冷弯卡环固位可摘局部义齿修复后在一定程度上可增加老年人基牙的患龋率和缺失率。     

Mastication in subjects with extremely shortened dental arches rehabilitated with removable partial dentures

Mastication was evaluated in subjects presenting extremely shortened dental arches (ESDAs) rehabilitated with mandibular free-end removable partial dentures (RPDs). Subjects were divided into four groups (n = 10): those with a complete dentition, those with ESDAs, and those with ESDAs who were rehabilitated with an RPD, who were evaluated both with and without their prostheses. Mastication was measured through masticatory performance, time, and ability. RPD wearers showed higher masticatory performance (P < .01) and ability (P < .001) and lower masticatory time (P < .001) than when not wearing their prostheses as well as ESDA subjects who had not received RPD therapy. Those with a complete dentition showed the best results (P < .001). It can be suggested that RPDs improve mastication in ESDA subjects but without achieving normal mastication levels.     

三种活动义齿基牙及其支持组织表面的应力分析

目的 :比较在局部可摘义齿修复中锻造卡环、铸造卡环和隐形义齿对基牙牙周组织表面应力的差异。方法 :分别用三种不同卡环的固位方式制作双侧游离端局部义齿 ,施加垂直压力 ,测试不同位点牙周组织表面应力。结果 :三种卡环义齿对基牙根尖部牙周组织的作用力无显著差别 ,而对牙颈部牙周组织及支承牙槽嵴的应力差异显著 (P <0 .0 5 ) ,具有统计学意义。结论 :在相同加载条件下 ,铸造卡环对牙颈部牙周组织产生的应力最大 ,隐形义齿对支承牙槽嵴产生的应力最大。     

Patient satisfaction following restoration of shortened mandibular dental arches in a randomized controlled trial

PURPOSE: Removable partial dentures (RPD) used to restore the severely shortened mandible may adversely affect the remaining natural teeth and are associated with a low prevalence of use. This pilot study investigated patient satisfaction following restoration of mandibular shortened dental arches. MATERIALS AND METHODS: Sixty subjects with mandibular shortened dental arches entered a randomized controlled trial comparing two types of mandibular prostheses: bilateral free-end saddle RPDs and distal cantilever resin-bonded fixed partial dentures (FPD). Patient satisfaction was assessed using self-administered questionnaires before (baseline), 3 months after, and 1 year after provision of new prostheses. RESULTS: Improvements in levels of general satisfaction with teeth, appearance of teeth, and perceived masticatory ability were significant for the FPD group. Significant improvements in perceived masticatory ability were noted for both groups. There were also significant improvements in perceived levels of comfort of mandibular prostheses in both groups. Changes in summary satisfaction scores indicated improved satisfaction for both treatment groups but suggested a larger clinical effect for the FPD group. Significant differences between treatment groups were not established. CONCLUSION: Patient-based outcomes reported suggested that resin-bonded cantilever FPDs are an effective means of restoring the shortened mandibular dental arch in terms of patient comfort and acceptance.     

Detection of improvement in the masticatory function from old to new removable partial dentures using mixing ability test

The aim of this study was to determine the sensitivity of the Mixing Ability Test to detect improvement of masticatory function in subjects on transition from old to new removable partial dentures. Thirty-two subjects (seven males, 25 females, mean age 65.0 years) with distal extension partially edentulous area in mandible and/or maxilla participated in the study. The following reasons were presented for replacing the old removable partial dentures with new ones: fracture and/or poor fitness of retainers, extraction of abutment teeth, poor fitness of denture base, severe wear of artificial teeth and request for metal base dentures. Masticatory function with old and new removable partial dentures after an adaptation period (mean 27.4 weeks) was evaluated by the Mixing Ability Test. Subjects were asked to masticate five two-coloured wax cubes with each removable partial denture. Mixing Ability Index was obtained from the colour mixture and shape of the masticated cubes. Wilcoxon signed-rank test was used to test the difference of Mixing Ability Indexes between old and new removable partial dentures. The mixing ability indexes with new removable partial dentures (mean+/- s.d.: 0.70+/- 0.68) was significantly higher (P<0.001) than those with old removable partial dentures (-0.11+/-1.13). The results suggest that the Mixing Ability Test was capable of detecting improvement in masticatory function with new removable partial dentures.     

Finite element stress analysis on the effect of splinting in fixed partial dentures

STATEMENT OF PROBLEM: Long-span fixed partial dentures usually require splinting of multiple abutments to overcome mechanical problems associated with the long edentulous span. Most information and indications for the use of multiple splinted abutments have been empirically derived. PURPOSE: This study analyzed the stress levels in the teeth and supporting structures of a fixed prosthesis and ascertained how the addition of multiple abutments in a fixed prosthesis modifies the stresses and their deflection. MATERIAL AND METHODS: The finite element method was used to analyze mechanical behaviors of a prosthesis and its supporting structures when a fixed prosthesis with several designs replaced a mandibular second premolar and a first molar. Variations of the standard finite element model were made by changing the number of splinted teeth and the level of bone support. RESULTS: A reduction of stress and deflection was observed in the supporting structures when a fixed partial denture was fabricated and teeth were splinted together. Increasing the number of splinted abutments did not reveal a proportional reduction of stress in the periodontium. Stress concentrations were seen in the connectors of prosthesis and in the cervical dentin area near the edentulous ridge. CONCLUSION: Increasing the number of the splinted abutment did not compensate for the mechanical problems of a long-span fixed partial denture sufficiently.     

Comparison of mandibular bone density and radiomorphometric indices in wearers of complete or removable partial dentures

Objectives To examine bone mineral density (BMD) and linear radiomorphometric parameters of the mandible in elderly patients with different types of dentures. Methods Patients had mandibular complete dentures (CDs) or Kennedy Class I removable partial dentures (RPDs) in the mandible; all patients had CDs in the maxilla. The age and sex distributions of patients with CDs and of those with RPDs were not significantly different. Three parameters were measured in dental panoramic radiographs (DPRs) from a total of 136 patients: thicknesses of the mandibular cortex below the mental foramen, the antegonion, and the gonion. Mandibular BMD was measured densitometrically using DPRs and a copper step wedge. All BMD values were expressed relative to the step wedge thickness. Results There was a significant difference between patients with CDs and those with RPDs for all the radiomorphometric indices measured (P < 0.001); specifically, radiomorphometric indices were higher in RPD wearers. Mandibular BMD values in RPD wearers were higher than those of patients with CDs, and BMD was significantly higher under the saddle in RPD wearers (P < 0.05). Conclusions These results support the hypothesis that occlusal forces that are transmitted directly to the mucosa beneath mucosa-borne dentures may cause overloading, which may cause bone resorption; by contrast, under tooth and mucosa-borne dentures, occlusal forces are transmitted not only to mucosa but also to the periodontal ligament of the abutment teeth, thereby reducing the transmission of force to the mucosa, which prevents overload. Greater chewing forces might thus be achieved with tooth and mucosa-borne dentures, which may stimulate bone growth at the mandibular cortex.     

Telescope retainers for removable partial dentures

Telescope crowns used in removable partial dentures reduce the destructive horizontal and rotational occlusal forces by directing them more axially an less traumatically than other retainers. These properties are combined with excellent conditions for cross-arch and multiple abutment splinting. If one of the abutment teeth needs extracting, the denture can be repaired with acrylic resin simply by remaking the secondary crown into a pontic.The single copings can be easily cleaned due to the good accessibility around their gingival margins. They also protect the abutment teeth against caries and thermal irritation.Soldering of the primary copings or their connection with accessory bars is not necessary in rigidly constructed telescope crowns, because the secondary crowns incorporated in the superstructure provide sufficient rigidity. In addition, the splinted copings often cause inflammatory gingival hyperplasia because the solder joints are too close to the gingival margins, preventing proper hygiene maintenance.The taper configuration or vertical height of the coping, which determines the amount of load transferred to each abutment, can be planned to suit each tooth's condition and designated function in the restoration. In a fixed restoration, the load is always evenly distributed among all the abutment teeth regardless of their condition, because the crowns are permanently cemented to them. In the telescope denture, the amount of force can be individually regulated by modifying the form and leverage of the retainers, according to their position, bone support, and occlusal conditions.     

Cantilever bridges or removable partial dentures in geriatric patients: a two-year study

The purpose of this study was to compare prosthetic, functional and occlusal conditions in twenty-seven patients treated with distally extending cantilever bridges and twenty-six patients treated with removable partial dentures (RPD) in the mandible. All patients had a complete upper denture. Mean age of the patients in both groups was about 69 years. The patients were under a supervised oral hygiene care throughout the 2-year study period. There were 6.9 +/- 1.7 mandibular teeth left in the bridge group and 7.5 +/- 1.7 in the RPD group and the mean number of posterior teeth (natural teeth/denture teeth/pontics) in occlusion was 4.1 +/- 1.1 and 7.3 +/- 1.4, respectively. During the study period signs and symptoms of mandibular dysfunction became significantly aggravated in the RPD group, P less than 0.05. A balanced occlusion in the muscular contact position was observed in 90% of the patients in the bridge group and in 76% of the RPD wearers. During the study period the need for dental or prosthetic treatment was negligible in the patients treated with bridges. In the RPD group, twenty-two teeth were restored with fillings due to caries and in eight patients major adjustments of the sublingual bar were necessary due to irritation of the oral mucosa. This study has shown that treatment with distally extending cantilever bridges in the mandible is a favourable alternative to treatment with removable partial dentures in elderly patients with a reduced dentition.     

Clinical examination and interleukin-1beta levels in gingival crevicular fluid in patients treated with removable partial dentures

PURPOSE: The purposes of this study were to investigate the periodontal status and susceptibility to periodontal disease progression of the teeth in contact with removable partial dentures (RPD) and to compare them with control teeth in mouths not restored with a partial denture, by means of both clinical parameters and interleukin (IL)-1beta levels in gingival crevicular fluid. MATERIALS AND METHODS: Twenty-eight periodontally healthy patients were selected for the study; 14 of them were treated with mandibular Kennedy Class I RPDs, and the other 14 patients were not restored for control. Clinical periodontal measurements were assessed, and crevicular fluid samples were collected from both abutment and control teeth to determine IL-1beta levels, which were measured by enzyme-linked immunosorbent assay. These procedures were performed both at baseline and 9 months after the insertion of the dentures. RESULTS: The wearing of RPDs resulted in statistically higher clinical scores and total IL-1beta levels compared to the baseline examination. In contrast, no statistically significant differences were found between baseline and 9-month examinations in the control group. CONCLUSION: RPDs are a risk factor for periodontal disease progression because of increased plaque accumulation associated with increased total IL-1beta levels and impaired clinical periodontal parameters.     

A 20-year retrospective survival study of fixed partial dentures

PURPOSE: This study of fixed partial dentures (FPDs) evaluated the long-term efficacy and determined frequencies and causes of failures. MATERIALS AND METHODS: A total of 322 FPDs in 193 patients, fabricated at an undergraduate university clinic, were evaluated over a 20-year period. All patients were invited to participate in a supportive maintenance program. Failures of the FPDs were divided into irreversible complications (loss of FPD/abutment) and reversible complications (FPD intact after conservative treatment) and into biologic and technical/patient-related failures. RESULTS: The Kaplan-Meier survival rate after 20 years was 66.2%. Statistically significant differences in survival rates were found between FPDs without post-and-core abutment teeth as compared to FPDs with at least one post-and-core abutment tooth (P = .002) and for vital abutments versus post-and-core abutments (P = .001), but significant differences were not found between restorations in the maxilla and mandible (P = .27). Caries and loss of retention were the main reasons for failure and accounted for 61% of the failures. CONCLUSION: The survival of FPDs by undergraduate students at a university clinic during a 20-year period was comparable to the results published by university departments or general practitioners. Occurrence of a previously reversible complication is a predictive factor for an irreversible complication later on. A reversible complication within the first 2 years will probably lead to an early irreversible complication.