Bone resorption in different parts of the mandible in patients restored with an implant overdenture. A retrospective radiographic analysis.

AIM: This study investigated the pattern of resorption of the mandibular ridge under implant-supported overdentures. MATERIAL AND METHODS: Files of 60 patients were available for analysis (45 women and 15 men, mean age at the time of the follow-up 76.5 ± 8.5 years, 54 patients restored with bars, 6 with ball anchors). A baseline was defined by different stable landmarks and quartered. Linear measurements from this baseline at different clinical relevant sites approximately at: (i) the area close to the mental foramen/close to the implant, (ii) the chewing center, and (iii) the distal edge of the denture flange were carried out on rotational tomograms (OPTs). The OPTs were taken after prosthetic restoration and at an individual follow-up time (mean 11 ± 4.75 years). The known implant length served to scale each measurement to avoid any distortion errors. RESULTS: The resorption rate showed a high individual variation, but among the three sites, the difference was highly significant. Median values of site (i) left = -0.07 mm/right = +0.05 mm, site (ii) left = -0.60 mm/right = -0.55 mm, and site (iii) left = -1.58 mm/right = -2.01 mm. CONCLUSIONS: The load of the distal flange of a mandibular implant overdenture increases bone resorption as a local factor, whereas implants may help to prevent resorption in the neighboring bone. An individual-adapted follow-up protocol should be established for each patient restored with an implant overdenture.

Space requirement of a prefabricated bar on two interforaminal implants: a prospective clinical study.

OBJECTIVES: This clinical study measured the dimensional changes of existing lower complete dentures due to the integration of a prefabricated implant bar. Additionally, the impact of this dimensional change on patient satisfaction and oral function was analyzed. METHODS: Twenty edentulous patients (10 men/10 women; aged 65.9 ± 11.8 years) received two interforaminal implants. Subsequent to surgery, a chair side adapted, prefabricated bar (SFI Bar(®), C+M, Biel, Switzerland) was inserted, and the matrix was polymerized into the existing lower denture. The change of the denture's lingual dimension was recorded by means of a bicolored, silicone denture duplicate that was sectioned in the oro-vestibular direction in the regions of the symphysis (S) and the implants (I-left, I-right). On the sections, the dimensional increase was measured using a light microscope. Six months after bar insertion, patients answered a standardized questionnaire. RESULTS: All dentures exhibited increased lingual volume, more extensively at S than at I (P = 0.001). At S, the median diagonal size of the denture was doubled (+4.33 mm), and at I, the median increase was 50% (I-left/-right = +2.66/+2.62 mm). The original denture size influenced the volume increase (P = 0.024): smaller dentures led to a larger increase. The amount of denture increase did not have negative impact on either self-perceived oral function or patient satisfaction. Approximately, 95% of the patients were satisfied with the treatment results. CONCLUSIONS: The lingual size of a lower denture was enlarged by the integration of a prefabricated bar without any negative side effects. Thus, this attachment system is suitable to convert an existing full denture into an implant-supported overdenture.

Long-term results of mandibular implants supporting an overdenture: implant survival, failures, and crestal bone level changes.

PURPOSE: The present study summarizes the long-term clinical observations of edentulous patients treated with mandibular implant-supported overdentures. MATERIALS AND METHODS: From 1984 to 1997, edentulous patients were consecutively admitted to treatment with mandibular implant overdentures. The treatment plan was to connect the dentures to only two implants by means of single ball anchors or bars; in patients with special oral conditions, three implants would be placed. Regular maintenance care was provided at least one time per year. The cumulative implant survival rate was calculated. Implant failures were described according to clinical signs at the time of removal and related to the patient's specific history. Crestal bone measurements were performed using computer software. RESULTS: In all, 147 patients with 314 implants were evaluated for 10 to 24 years. Of these, 101 patients were still available; of the 46 patients who were not evaluated, 26 had died or were not ambulatory. Thirteen implants failed during the observation period, resulting in a cumulative survival rate of 85.9% after 24 years. The reasons for removal of implants were peri-implantitis (two implants) and mobility (11 implants). Mean crestal bone loss was 0.54 ± 0.7 mm per implant site after an average observation time of 16.5 ± 3.9 years. The duration of loading had a statistically significant effect on bone loss. CONCLUSIONS: The present data exhibit a satisfactory survival rate of implants. An individual analysis of implants with late failures did not reveal a typical failure pattern, but loss of implants without signs of infection was more frequent than loss of implants with signs of peri-implantitis.

[Does the combination syndrome exist? A case report]. / Existiert das Kombinationssyndrom? Ein Fallbericht.

This case report documents the prosthetic rehabilitation of a patient showing the typical features of combination syndrome. This case documentation gives a general overview of the suspected development and the prevalence of this "syndrome". A treatment option should be shown by the example of a patient from the starting situation until the prosthetic therapy by means of a complete maxillary denture and an implant-supported mandibular overdenture rigidly retained with a milled bar.