Clinical outcomes of different implant types in mandibular bar-retained overdentures: a retrospective analysis with up to 20 years follow-up.

PURPOSE: To determine the clinical and radiological outcomes of hybrid-design- (HD) and bone-level (BL) implants for bar-retained mandibular implant-overdentures (IODs). METHODS: For this retrospective study, edentulous patients who had received maxillary complete dentures and mandibular bar-retained IODs were invited for a follow-up assessment. Implant survival, implant success and health of peri-implant tissues were assessed on an implant level-based analysis. Patient-based parameters served to identify risk factors for peri-implant bone loss, presence of peri-implantitis and success. RESULTS: Eighty patients (median age 72.72 [67.03; 78.81] years, 46 females) with 180 implants (median follow-up 12.01 [10.82; 21.04] years) were assessed. There was no difference concerning the rate of implant failure (p = 0.26), or peri-implantitis (p = 0.97) between HD and BL implants. Solely in one study group, there was the presence of peri-implant pus. Implant success was higher in BL implants with one group being notably higher than the comparing groups (p = 0.045). For bone loss, a width of keratinized mucosa (KM) ≤ 1 mm (p = 0.0006) and the presence of xerostomia (p = 0.09) were identified as risk factors. Smoking (p = 0.013) and a higher body mass index (BMI) (p = 0.03) were a risk factor for peri-implantitis. As risk factors for reduced implant success, a small width of KM (p = 0.003) and the presence of xerostomia (p = 0.007) were identified. CONCLUSIONS: For mandibular bar-retained IODs, both BL and HD implants are mostly successful. A minimum of 1 mm KM around implants and normal salivary flow are relevant factors for implant success and stable peri-implant bone levels. Smoking and a high BMI are potential risk factors for peri-implantitis.

Determination of the occlusal vertical dimension in edentulous patients using lateral cephalograms.

The determination of the occlusal vertical dimension (OVD) in edentulous patients is based on clinical assessment with high variability. This study tested the hypothesis: The average OVD in edentulous patients with conventional dentures is too low compared to orthodontic norms, when only clinical parameters are used for the determination of the OVD. Edentulous patients with conventional full dentures were enrolled. Clinical parameters were judged by two senior prosthodontists. Digital lateral cephalograms were taken and served to calculate the OVD according to the lower face height angle (ANS-Xi-D) taking tooth-independent facial growth patterns into account. The ANS-Xi-D angle was compared with reference values by applying one-sample mean comparison tests. Thirty-six participants (17 female, 19 male; mean age 65.3 ± 10.6 years) were enrolled in this study. Clinically, the OVD of four dentures was judged too low, in one case too high, and in the other 31 cases as correct. The mean ANS-Xi-D angle was 48.28°±4.86 and statistically not different to the norm value of 49°±4 (n.s.). There was a tendency that the ANS-Xi-D angle was different between participants with different tooth-independent facial growth patterns (ANOVA, P = .0548). Predominantly, clinically sufficient prostheses show adequate ANS-Xi-D angles. Short-face type denture patients are often restored to comply with mesiofacial norms. The determination of the OVD based on lateral cephalography is not recommendable to be a standard diagnostic parameter. Orthodontic norms are derived from dentate cohorts and might not take the continuing facial growth and other confounding factors of edentulous subjects into account.

Influence of platform switching on bone-level alterations: a three-year randomized clinical trial.

The concept of platform switching has been introduced to implant dentistry based on clinical observations of reduced peri-implant crestal bone loss. However, published data are controversial, and most studies are limited to 12 months. The aim of the present randomized clinical trial was to test the hypothesis that platform switching has a positive impact on crestal bone-level changes after 3 years. Two implants with a diameter of 4 mm were inserted crestally in the posterior mandible of 25 patients. The intraindividual allocation of platform switching (3.3-mm platform) and the standard implant (4-mm platform) was randomized. After 3 months of submerged healing, single-tooth crowns were cemented. Patients were followed up at short intervals for monitoring of healing and oral hygiene. Statistical analysis for the influence of time and platform type on bone levels employed the Brunner-Langer model. At 3 years, the mean radiographic peri-implant bone loss was 0.69 ± 0.43 mm (platform switching) and 0.74 ± 0.57 mm (standard platform). The mean intraindividual difference was 0.05 ± 0.58 mm (95% confidence interval: -0.19, 0.29). Crestal bone-level alteration depended on time (p < .001) but not on platform type (p = .363). The present randomized clinical trial could not confirm the hypothesis of a reduced peri-implant crestal bone loss, when implants had been restored according to the concept of platform switching.

[On quality of life after surgical therapy of oral cancer - a retrospective multi-center study: the connection between dedentition, denture, quality of life, and dysphagia, and the resulting rehabilitation schemes]. / Zur Lebensqualität nach chirurgischer Therapie von Mundhöhlenkarzinomen - eine retrospektive Multicenterstudie: Der Zusammenhang zwischen Zahnverlust, Zahnersatz, Lebensqualität und Dysphagie sowie die daraus resultierenden Massnahmen bei der Rehabilitation.

PURPOSE: The surgical treatment of oral cancer results in functional and aesthetical impairments. Patients' quality of life is considerably impaired by oral symptoms resulting from therapy of oral cancer. In many cases the inevitable resection of the tumor, as well as the adjuvant radiochemotherapy will cause the destruction of physiologically and anatomically important structures. One focus of research was the specific rehabilitation of dental loss by functional dentures. Another was the course of 19 impairments (comprehension of speech for unknown others, comprehension of speech for familiar others, eating/swallowing, mobility of the tongue, opening range of the mouth, mobility of lower jaw, mobility of neck, mobility of arms and shoulders, sense of taste, sense of smell, appearance, strength, appetite, respiration, pain, swelling, xerostomia, halitosis). METHODS: Commissioned by the German, Austrian and Swiss cooperative group on tumors of the maxillofacial region (DOSAK), data were collected in 3.894 questionnaires at 43 hospitals in Germany, Austria and Switzerland. The catalogue comprised 147 items in 9 chapters. At the end of the enquiry, 1.761 anonymous questionnaires were returned by 38 hospitals. 1.652 of these could be evaluated regarding the question. RESULTS: The sum score of the 19 impairments was highly increased immediately after the operation and recovered over the next 6 months, without, however, reaching the pre-surgery level. Of 1.652 patients, only 35% did not lose any teeth during therapy. 23% lost up to 5, 17% up to 10 teeth. A quarter of the patients lost more than 10 teeth. The more teeth were lost, the greater the decline of quality of life (p < or = 0.001), although this could be allayed by the functionality of the dentures (p < or = 0.001). There is a reciprocal dependence between the functionality of dental prosthetics and impairment by eating/swallowing (p < or = 0.001). CONCLUSIONS: Patients' quality of life after radical surgery of a carcinoma of the oral cavity depends not only on the functionality of dentures and the specificity of rehabilitation, but also from the initial findings, the extent and location of the resection, the chosen therapy, the general circumstances of the patient's life as well as their strategies of coping. These factors, however, unlike those of functionality of dental prosthesis and rehabilitation, are not modifiable.