Implant overdentures: recommendations and analysis of the clinical benefits.

Due to the progress made in implantology, in recent years the interest in prosthetic rehabilitation in edentulous mouths using overdentures has increased considerably. Indications to the treatment of implant supported overdenture could be classified in three groups: the first group consists of younger members of the elderly population who have an edentulous upper jaw rehabilitated with a conventional complete denture but experience discomfort with it and therefore desire a stable prosthesis and greater comfort in the mouth; the second group, for which the use of implant overdentures is recommended, consists of older patients who require greater stability from a complete mandibular denture; the third group consists of compromised patients and those with acquired or congenital maxillofacial conditions. Moreover, advantages of overdentures supported by implants are analyzed; in fact, they allow a lower bone reabsorption, a better retention and stability of the prosthesis than the traditional complete denture, an increased masticatory effectiveness, a reduction of pain during mastication tanks to the higher stability, a better sensory perception, a considerable patient satisfaction, and the option of making an immediate prosthetic rehabilitation with implants through immediate load.

Diagnosis and treatment of dens invaginatus with open apex in a young adult patient by using cone-beam computed tomography and operative microscope.

BACKGROUND: Dens invaginatus is a developmental anomaly that can affect both deciduous and permanent dentition. The anomaly is caused by the invagination of the enamel organ into the dental papilla prior to the calcification of the dental tissues. The treatment option changes according to the classification, from the simple filling of the invaginated enamel area to root canal treatment with or without retrograde surgery, intentional re-implantation, or the extraction of the affected tooth. CASE REPORT: In this study we report a case of a maxillary lateral incisor invaginatus in a young adult patient. The periapical endoral X-ray showed the presence of a periapical radiolucency in tooth 22, that had a structure similar to a tooth inside it and an immature apex. Cold thermal testing showed that it was not a vital tooth. CBCT confirmed the diagnosis of Oehler Class II dens invaginatus. The treatment plan involved root canal treatment of both the "true" and the "invaginated" canal using calcium hydroxide-based intermediate medication. Then, after removing the hard internal structure with the aid of an operative microscope, MTA was used to close the immature apex. Finally, the large endodontic space was filled with self-etching, self-adhesive, dual curing resin cement. The patient was included in a follow-up programme to monitor and verify the complete healing of the periapical bone of the affected tooth. CONCLUSION: The use of technology and of special materials allowed an adequate management and resolution of the case reported.

Effect of cyclic loading on fracture strength and microleakage of a quartz fiber dowel with different adhesive, cement and resin core material combinations.

AIM: This study evaluated the performance of different adhesive-cement-core combinations coupled with quartz fiber dowels after cyclic loading and fracture strength tests and assessed the microleakage using dye penetration method. METHODS: Forty maxillary canines (N=10 per group) were restored with fiber dowels (Quartz fiber DT Light Post) and four adhesive-cement-core material combinations (Group 1: All-Bond 2+C&B [root]/All-Bond 2+Biscore [core]; Group 2: All-Bond 2+Bisfil 2B [root]/All-Bond 2+Bisfil 2B [core]; Group 3: Scotchbond 1+RelyX ARC [root]/Scotchbond 1+Supreme [core]; Group 4: RelyX Unicem [root]/Scotchbond 1+Filtek Supreme [core]). The specimens were initially cyclic loaded (x2,000,000, 8 Hz, 3 to 100 N at 45 °C under 37±3 °C water irrigation) and then immersed in 0.5% basic fuchsine at 37 °C for 24 hours for dye penetration and interface failure detection. The failure surfaces were observed under the stereomicroscope (x100 magnification). Circumferential and centripetal dye penetration was scored at the buccal and lingual sites. RESULTS: Only three specimens failed macroscopically during cyclic loading. No significant difference was found among the groups for the number of resisted cycles (P=0.9). Mean fracture strength between the groups were also not statistically significant (213±63-245±71 N) (P=0.740) (ANOVA). All four groups showed high values of dye penetration along the restoration interfaces being not significant from each other (P=0.224) (Kruskal-Wallis). The lingual sides of the teeth where the load applied, showed significantly higher incidence of detachment between the core and the dentin (100%, 90%, 100%, 90% for groups 1, 2, 3, 4, respectively) compared to the buccal side (30%, 30%, 60%, 40%) (P=0.032, c2 test). In 13 specimens (32.5%) crack lines at the coronal area were observed. Fracture strength was not significantly correlated with dye penetration (P=0.1803, r=-0.2162, Linear Regression and Correlation test). CONCLUSION: Different combinations of adhesive-cement-composite core materials for the fiber post tested performed similar under cyclic loading and fracture strength tests.

[Edentulousness and prosthetic treatment needs in a sample of the adult inhabitants of Palermo (Italy)]. / Condizioni di edentulismo e necessità di trattamento prote- sico in un campione della popolazione adulta della città di Palermo.

The aim of this study was to evaluate the level of edentulousness and the prosthetic treatment need in a sample of the over 18-year-old inhabitants of Palermo (Italy). A stratified sample of 385 subjects (183 female and 202 male) was taken to represent the population of the city. Each subject included in the study was examined to record the level of edentulousness (complete edentulousness, partial edentulousness, intact dentition) and the level of denture wearing. Requirement for repair of dentures was recorded according to the marginal fitting for fixed dentures, and to the extension, stability and retention for removable dentures. Complete edentulousness of one or both arches was present in 4,6% of the studied population, whereas 184 (34.8%) of the sample population had intact dentition. Partial edentulousness was present in 60.6% of the subjects surveyed, but only the 45.9% of these was wearing dentures. Loss of structural integrity or incongruous marginal fitting was found in the 37.9% of fixed dentures. The majority of partial and complete removable dentures (74.5%) did not ever undergo relining, and the 51.7% of them needed relining or replacement. Statistical analysis (chi-square test) showed that the level of edentulousness was correlated with age; similarly, the frequency of dental visits significantly impacted on the number of missing tooth (P < 0.01). The results of the present study show that the adult inhabitants of Palermo had high level of partial edentulousness and low level of denture wearing. The majority of existing removable dentures required relining or replacement.

Cytotoxicity of four types of resins used for removable denture bases: in vitro comparative analysis.

AIM: The aim of this paper was to compare the cytotoxicity of four types of resins used for manufacturing denture bases. METHODS: Nine disk-shaped samples of four resin (two heat-polymerized, one auto-polymerized, and one light-polymerized), 9 samples of glass (negative control) and 9 samples of lead (positive control) were made according to the manufacturer instructions. The materials were tested by contact with BALB/C 3T3 fibroblast cells. Each sample was tested after 24, 48 and 72 hours. The cellular vitality was verified through spectrophotometric analysis of the solution where the colour is directly related to the amount of metabolically active and living cells. The results were analyzed through the one way variance analysis (ANOVA) in order to evaluate significant differences in the behaviour of the resins at 24, 48 and 72 hours. When a significant difference was present, the Games/Howell test for multiple comparisons was used. The significativity level was fixed at P0.05). The light-polymerized resin and the negative control (glass) were so compatible with the cellular carpet that all their values did not show statistically significant differences in any of the three periods of time considered (p>0.05), and their cellular vitality values almost reached the 100%. CONCLUSIONS: The autopolymerized resin showed the major cytotoxicity; the light-polymerized resin, instead, showed an optimal biocompatibility due to the absence of free monomer from its chemical composition.

[Overdenture supported by natural teeth: analysis of clinical advantages]. / Overdenture su denti naturali. Analisi dei vantaggi clinici.

Hybrid prosthesis supported by natural teeth (overdenture) is widely used in clinical practice and should be executed whenever the clinical conditions suggest it. Through a critical review of the literature, the anatomical, functional, psychological and clinical advantages are emphasized. Among the first ones, the prophylaxis of residual anatomical components, due to the limitation of bone resorption, and the preservation of sensorial proprioception are relevant. Important advantages are also represented by a better crown-root ratio of residual teeth supporting overdenture, with the consequent improvement of the longitudinal prognosis of such teeth. The greater retention and stability of overdenture in comparison with complete denture greatly improve the masticatory efficacy. The psychological advantages resulting from the dental anchorage, which allows the patient to be more confident in social life, are also relevant. Finally, when the dental support is lost, converting overdenture into complete denture is simple and quick, and makes easier the longitudinal clinical maintenance of the denture.