Implant Placement under Existing Removable Dental Prostheses and the Effect on Follow-Up and Prosthetic Maintenance.

PURPOSE: The aim of this prospective clinical study was to compare the maintenance interventions required for solely implant-retained overdentures (I-OD) with that of overdentures retained by a combination of telescopic crowns and implants (T/I-OD). MATERIALS AND METHODS: The participants in this study were 22 patients who initially presented either with a removable complete denture (n = 11) or with an overdenture retained by 1 to 2 telescopic crowns on natural teeth (n = 11). Subsequently, the total number of abutments was increased to 5 to 6 (maxilla) or 4 to 5 (mandible) by placing implants in strategically advantageous regions, generating two distinct groups: I-OD and T/I-OD. Ball attachments were connected to the implants and integrated into the existing denture. The maintenance aspects were analyzed according to the type of treatment (preventive, biological, and technical) and to the severity of treatment (minimal, moderate, and extensive). RESULTS: During a mean observation time of 6.5 years, the tooth survival rate was 89% (T/I-OD) and the implant survival rate 100% (both groups). The survival rates of the overdentures ranged from 90.9% (I-OD) to 100% (T/I-OD). A mean number of 0.6 (I-ODs) and 2.0 (T/I-OD) treatments were performed for biological reasons; and 8.2 (I-ODs) and 9.6 (T/I-OD) for technical reasons, per patient, during the observation time. From biological aspects, significantly more extensive maintenance was found to be necessary in the T/I-OD group than in the I-OD group. CONCLUSIONS: The therapeutic concept of implant placement under existing prostheses was promising when performed in indicated cases.

Implant placement under existing removable dental prostheses and its effect on oral health-related quality of life.

OBJECTIVE: One aim of this prospective clinical study was to measure the effects of strategicimplant placement under removable partial dental prostheses (RPDPs) and among removable complete dental prostheses (RCDPs) on oral health-related quality of life (OHRQoL). MATERIALS AND METHODS: Twenty-three patients participated in this study restored with RCDPs (n = 12) or RPDPs retained by telescopic crowns with 1-2 abutment teeth (n = 11). The total number of abutments was increased to 5-6 (maxilla) or to 4 (mandible) by placing implants in strategically advantageous regions. Ball attachments were attached to the implants and integrated in the existing denture. The Oral Health Impact Profile (49 questions) was completed by patients before implant placement, at baseline (integration of ball attachments), and during 12- and 24-month follow-up visits. RESULTS: There were marked reductions of impacts in both groups when comparing pre-treatment scores and scores at baseline (P < 0.0001), 12-month (P < 0.0001), and 24-month follow-up visits (P < 0.0001), respectively. For none of the visits, a significant difference between the two groups was detected (P > 0.05). CONCLUSION: It can be concluded that a strategic placement of implants under the existing dental prostheses improves OHRQoL in both treatment groups.

Does the Oral Health Impact Profile questionnaire measure dental appearance?

PURPOSE: The aim of this study was to evaluate whether there is a need to develop a new questionnaire measuring dental appearance or if this is already covered by the Oral Health Impact Profile (OHIP-49). MATERIALS AND METHODS: Based on internationally accepted guidelines about dental esthetics, a questionnaire was developed to measure dental appearance (QDA). Eleven items defined a QDA sum score (0 = absolutely satisfied, 44 = absolutely dissatisfied). Furthermore, oral health-related quality of life was evaluated using the German version of the OHIP-49 and the OHIP-esthetic. Thirty patients (14 women, 16 men; mean age 59 +/- 10 years) were included in the study. All patients received a complete oral rehabilitation including the anterior teeth of the maxilla. Questionnaires were completed before and after treatment. RESULTS: The median values were 16 and 1.5 for the QDA sum score, 46 and 16 for the OHIP sum score, and 14.5 and 2 for the OHIP-esthetic before and after rehabilitation, respectively. The improvement after treatment was significant for all questionnaires (P < or = .0001). Between the QDA sum score and the OHIP sum score or any of the OHIP subscales (the only exception being "psychological discomfort"), no significant correlation could be found (P > .05). Between the QDA sum score and the OHIP-esthetic, a significant correlation could be found before treatment (r = 0.505, P = .004) but not after treatment (P > .05). CONCLUSIONS: If the OHIP-49 is used in clinical studies and a profound evaluation of dental appearance is desired, it is reasonable to use an additional esthetic modulus.

Psoriasis of the tongue.

INTRODUCTION: Psoriasis is a common, chronic dermatologic disease. Cases affecting the oral mucous membranes are rarely reported in the international literature, in particular tongue lesions are hardly ever documented. MATERIAL AND METHODS: This article presents a 61 year old patient with persistent whitish lesion on his tongue. Biopsy specimens from mid surface and tip of the tongue were taken. Histopathologic sections were stained with haematoxylin-eosin (H-E) as well as with Periodic acid-Schiff (PAS) and examined by light microscopy. RESULTS: Tongue lesions showing epithelial hyperplasia, parakeratosis, long papillae, neutrophils and microabscesses of Munro. CONCLUSIONS: The reported case suggests that the clinical and histological appearances of the lesions are consistent with mucosal psoriasis.

Retrievability of implant-retained crowns following cementation.

OBJECTIVES: The purpose of this study was to assess the retrievability of cemented implant crowns using two different removal devices. The influence of five cement types and two cement application techniques was evaluated. METHODS: Forty copings were cast from a CoCr alloy for 40 tapered titanium abutments (5 degrees taper, 4.3 mm diameter, 6 mm height, Camlog, Germany). Twenty copings were modeled as single crowns, whereas 20 copings were modeled with an extension to simulate fixed partial dentures (FPDs). Before cementation, the inner surfaces of the copings were air-abraded (50 mum Al(2)O(3) particles at 2.5 bars), while the abutments were used as delivered with machined surfaces. Copings were cemented with eugenol-free zinc oxide (Freegenol), zinc phosphate (Harvard), glass ionomer (Ketac Cem), polycarboxylate (Durelon) and so-called self-adhesive resin (RelyX Unicem) cement. Cement was applied in a thin film band of 1 or 3 mm to the cervical margin of the inner surface of the copings, respectively. After cementation, specimens were stored in saline solution for 24 h. The Coronaflex and a standardized custom-made removal device were used to remove the copings from the abutments. RESULTS: Using the same cement, no statistically significant influence with regard to the type of restoration (crown/FDP), cement application mode and device was detected (P>0.05). Therefore, data of specimens cemented with the same cement were pooled. Median attempts to remove the copings were: zinc oxide: 3, self-adhesive resin: 3, zinc phosphate: 5, glass ionomer: 16 and polycarboxylate: 58. Four levels of significance (P<0.0001) were found: (1) zinc oxide/self-adhesive resin; (2) zinc phosphate; (3) glass ionomer; and (4) polycarboxylate. CONCLUSIONS: Zinc phosphate and glass ionomer cement might be suitable for a so-called 'semipermanent' (=retrievable) cementation, while polycarboxylate seems to provide the most durable cementation.

Durability of the resin bond strength to zirconia ceramic after using different surface conditioning methods.

OBJECTIVES: The purpose of this in vitro study was the evaluation of the bond strength and its durability of two composite resins to zirconia ceramic after using different surface conditioning methods. METHODS: Plexiglas tubes filled with composite resin were bonded to zirconia ceramic discs (Cercon) which were either in their original state as supplied by the manufacturer only cleaned in isopropanol or were cleaned with an air-powder-water spray with sodium hydrocarbonate solution or were air abraded (50 microm Al(2)O(3)). Groups of 20 specimens each were bonded either with a conventional composite resin (Variolink II) or with a phosphate monomer (MDP)-containing resin (Panavia F) to the ceramic discs. Subgroups of 10 bonded specimens were stored in distilled water (37 degrees C) for either 3 days or for 150 days. Additionally, the 150 days specimens were thermal cycled 37,500 times. Statistical analyses were conducted with the Wilcoxon rank sum test adjusted by Bonferroni-Holm. RESULTS: The initial tensile bond strength (TBS) for Variolink II ranged from 9.0 to 16.6 MPa and were significantly lower (p< or =0.05) than for Panavia F ranging from 18.7 to 45.0 MPa. Air abrasion resulted in significantly higher TBS (p< or =0.01) than the two other surface conditioning methods. After 150 days storage, only the air abraded specimens bonded with Panavia F showed high bond strengths of 39.2 MPa, whereas most other specimens debonded spontaneously or showed very low bond strengths. SIGNIFICANCE: The use of the MDP-containing composite resin Panavia F on air abraded zirconia ceramic can be recommended as promising bonding method.

Retention forces and seating discrepancies of implant-retained castings after cementation.

PURPOSE: The purpose of this in vitro study was to evaluate the influence of cement type and application technique on seating discrepancies and retention forces of noble alloy castings cemented on titanium abutments. MATERIALS AND METHODS: Eugenol-free zinc oxide (Freegenol), zinc phosphate (Harvard), glass ionomer (KetacCem), polycarboxylate (Durelon), and self-adhesive resin (RelyX Unicem) cements were used. The inner surfaces of the castings were either completely coated or half-coated with cement. Abutments were used as delivered with a machined surface for the first part of the study. Groups of 8 castings were cemented in both ways. For the second part of the study, the abutments were air-abraded (aluminum oxide, 50 microm particle size), and groups of 8 completely coated castings were cemented with all cements. Marginal discrepancies were measured before and immediately after cementation. Tensile tests were conducted to measure the retention forces. Statistical analysis was performed with pair-wise comparison using the Wilcoxon rank sum test modified by Bonferroni-Holm. RESULTS: Change in seating discrepancies did not differ significantly among the different application techniques. The median retention forces for completely-coated castings were 177 N for eugenol-free zinc oxide, 346 N for zinc phosphate, 469 N for glass ionomer, 813 N for polycarboxylate, and 653 N for self-adhesive resin. With respect to retention force, 3 significantly different groups (P < .05) were identified: (1) zinc oxide, (2) zinc phosphate/glass ionomer, and (3) polycarboxylate/self-adhesive resin. No differences in retention between the 2 coating techniques were found for any cement. However, air abrading the abutments resulted in increased retention of the castings for some of the cements. CONCLUSIONS: Half-coating of the restorations with cements did not result in reduced retention values compared to the complete coating technique, but air abrasion resulted in increased retention with some cements.