ObjectivesThe purpose of this study was to evaluate the oral health-related quality of life of patients treated with implant-supported mandibular overdentures and to compare the attachment systems used.Material and MethodsAltogether 112 patients treated with implant-supported mandibular overdentures in 1985 - 2004 were invited to the follow-up; 58 of them attended and replied to the Oral Health Impact Profile (OHIP-14) -questionnaire. There were 48 overdentures with a bar connection and 10 with a ball connection, the total number of implants installed and still in use was 197. The mean follow-up time was 13.7 years. The associations between the OHIP-14 variables and the patient's age, gender as well as the number of implants supporting the overdenture and the type of attachment used were assessed.ResultsThe results showed that patients with implant-supported mandibular overdentures were satisfied with their oral health-related quality of life (OHRQoL). Older patients were more satisfied than younger ones in both genders. Neither the implant connection type nor the number of supporting implants seemed to have a significant influence on the OHRQoL.ConclusionsEspecially older patients with mandibular implant-supported overdentures were satisfied with their oral health-related quality of life. Attachment type or the number of supporting implants did not have a significant influence on the oral health-related quality of life.

ObjectivesTo systematically review risks of mechanical impact on peri-implant strain and prosthetic influence on stability across finite element studies.Material and MethodsAn online literature search was performed on MEDLINE and EMBASE databases published between 2011 and 2016. Following keywords tiered screening and selection of the title, abstract and full-text were performed. Studies of finite element analysis (FEA) were considered for inclusion that were written in English and revealed stress concentrations or strain at peri-implant bone level.ResultsThere were included 20 FEA studies in total. Data were organized according to the following topics: bone layers, type of bone, osseointegration level, bone level, design of implant, diameter and length of implant, implant-abutment connection, type of supra-construction, loading axis, measurement units. The stress or strain at implant-bone contact was measured over all studies and numerical values estimated. Risks of overloading were accented as non-axial loading, misfits, cantilevers and the stability of peri-implant bone was related with the usage of platform switch connection of abutment.ConclusionsPeri-implant area could be affected by non-axial loading, cantilever prosthetic elements, crown/implant ratio, type of implant-abutment connection, misfits, properties of restoration materials and antagonistic tooth. The heterogeneity of finite element analysis studies limits systematization of data. Results of these studies are comparable with other findings of in vitro, in vivo, prospective and retrospective studies.

Outcome of implant-supported overdenture treatment -a survey of 58 patientsObjective: The aim of this follow-up study was to evaluate the long-term outcome of implant-supported or implant-retained mandibular overdenture treatment. Material and methods: Altogether 112 patients treated with implant-supported overdentures between 1985 and 2004 were invited to the follow-up and 58 attended the clinical examination. The total amount of implants examined and still in use was 197. The average number of implants installed was three (range 2-4), and the mean length of the implants was 12 mm (range 8-21 mm). There were altogether 48 overdentures with a bar connection and 10 with a ball connection. Results: The most frequent prosthetic complications were technical: loosening of the retentive mechanism (39.7%) and breakage of the matrices (5.2%). The most common peri-implant soft-tissue findings were bleeding and slight hyperplasia. The implant-supported overdentures of 19 patients (32.8%) had been renewed, while 39 patients (67.2%) still used their original overdentures, of which the oldest was 20 years old. Conclusion:The results of this long-term follow-up study show that the outcome of implant-supported mandibular overdenture treatment was excellent. The patients were satisfied with the treatment, regardless of the attachment type used. Removable overdentures are more easy to clean and can be cleaned outside the patient's mouth, whereas fixed-implant full-arch dentures in the edentulous mandible require much more time-consuming hygiene. This kind of overdenture treatment is suitable also in the elderly, even though their ability to practice appropriate oral hygiene might be decreased.

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