Bisphosphonate treatment and dental implants: A systematic review.

BACKGROUND: To analyze articles that studied patients submitted to diphosphonates therapy and who received dental implants before, during or after bisphosphonate (BP) treatment, compared to healthy patients, analyzing the increase of failure and loss of implants or bisphosphonate related osteonecrosis of the jaw (BRONJ) incidence. MATERIAL AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used in this study. The clinical question in "PICO" format was: In patients under bisphosphonate therapy, do dental implants placement, compared to healthy patients, increase the failure and loss of implants or bisphosphonate related osteonecrosis of the jaw incidence? PubMed/MEDLINE was searched for articles published up until April 15, 2015 using a combination of MeSH terms and their Entry terms. RESULTS: The search resulted in 375 articles. After selection according to the eligibility criteria, 15 studies fulfilled were included (eight retrospective, one prospective and six case series), with a total of 1339 patients analyzed, 3748 implants placed, 152 loss of implants and 78 cases of BRONJ. CONCLUSIONS: Due to the lack of randomized clinical trials looking at this theme, further studies with longer follow-up are needed to elucidate the remaining questions. Thus, it is wise to be careful when planning dental implant surgery in patients undergoing bisphosphonate therapy because of the risk of developing BRONJ as well as occurring failure of implant. Moreover, complete systemic condition of the patient must be also taking into considering when such procedures are performed.

Influence of post system and remaining coronal tooth tissue on biomechanical behaviour of root filled molar teeth.

AIM: To investigate ex vivo the influence of post system and amount of remaining coronal tooth tissue on the fracture resistance, fracture mode and strain of root filled molar teeth. METHODOLOGY: Seventy mandibular human molar teeth were divided into seven groups (n = 10), one control (sound teeth) and six experimental groups resulting from the interaction between the two study factors: post system (Pa, post absence; Gfp, glass fibre post; Cmp, cast Ni-Cr alloy post and core) and amount of remaining coronal tooth tissue (Fe, 2 mm of ferrule; NFe, no ferrule). Teeth in the experimental groups were restored with metal crowns. For the strain gauge test, two strain gauges per sample were attached on the buccal and proximal root surfaces, and the samples of each group (n = 5) were submitted to a load of 0-100N. Fracture resistance (N) was assessed in a mechanical testing device (n = 10). Strain gauge and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's HSD and Duncan's test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: The absence of ferrule was associated with lower fracture resistance regardless of the post system. Groups restored with glass fibre post and cast Ni-Cr alloy post and core had similar fracture resistance and higher values than groups without posts, regardless of the remaining coronal tooth tissue. Teeth with no ferrule and cast Ni-Cr alloy post and core resulted in catastrophic fractures and those with no ferrule and glass fibre post or no ferrule and post absence resulted in restorable failures. Buccal strain was higher in sound teeth and lower in teeth without posts. Glass fibre post insertion decreased the buccal strain compared to the teeth with ferrule and absence of post. CONCLUSIONS: Two millimetre of ferrule had a significant influence on cusp strain, fracture resistance and failure mode. The glass fibre post was as effective as the cast Ni-Cr alloy post and core in the restoration of root filled molars regardless of the remaining tooth tissue. Absence of a post decreased the fracture resistance and increased the cusp strain.

Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores.

AIM: To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns. METHODOLOGY: Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 x 10(5) 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0-100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were analysed by one-way anova and Tukey Honestly Significant Difference (HSD) test (alpha = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the von Mises criteria. RESULTS: No significant difference in fracture resistance values and fracture modes occurred between the four groups. The BLd group had higher stress concentrations in the buccal dentine and higher strain values on the proximal surfaces. CONCLUSIONS: The anti-rotation devices did not influence significantly the fracture resistance and fracture mode. However, the stress-strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly.