Dental implant placement through impacted teeth or residual roots as an alternative to invasive extraction surgeries: a systematic literature review.

This work systematically reviews dental implant placement through impacted teeth or residual roots, as an alternative to invasive extraction surgeries, evaluated in terms of survival rates, marginal bone loss, surgical, and prosthetic complications. The authors conducted an electronic search of four databases up to September 2020; also a complementary handsearch was carried out. The quality of the included studies was assessed using a protocol for assessment of risk of bias in exposure studies. Ten studies fulfilled the inclusion criteria and were analysed. A total of 44 patients received 62 dental implants and were monitored for a minimum of 12-months follow-up. An overall mean implant survival rate was 90.32%, reporting 97.56 % for dental implants through impacted teeth and 76.19% through residual roots. No surgical or prosthetic complications were reported. Placing dental implants through impacted teeth may offer a valid therapeutic option for implant-supported restorations in patients for whom surgery and orthodontic traction are not possible, and/or patients who refuse to undergo more invasive extraction surgery. Moreover, additional caution is recommended when placing implants through retained root fragments, as this may involve long-term risk. Further research generating long-term data are needed to confirm these findings.

Loading and release of doxycycline hyclate from strontium-substituted calcium phosphate cement.

Novel Sr-substituted calcium phosphate cement (CPC) loaded with doxycycline hyclate (DOXY-h) was employed to elucidate the effect of strontium substitution on antibiotic delivery. The cement was prepared using as reactants Sr-substituted beta-tricalcium phosphate (Sr-beta-TCP) and acidic monocalcium phosphate monohydrate. Two different methods were used to load DOXY-h: (i) the adsorption on CPC by incubating the set cement in drug-containing solutions; and (ii) the use of antibiotic solution as the cement liquid phase. The results revealed that the Sr-substituted cement efficiently adsorbs the antibiotic, which is attributed to an enhanced accessibility to the drug-binding sites within this CPC. DOXY-h desorption is influenced by the initial adsorbed amount and the cement matrix type. Furthermore, the fraction of drug released from CPCs set with DOXY-h solution was higher, and the release rate was faster for the CPC prepared with 26.7% Sr-beta-TCP. The analysis of releasing profiles points to Fickian diffusion as the mechanism responsible for antibiotic delivery. We can conclude that Sr substitution in secondary calcium phosphate cements improves their efficiency for DOXY-h adsorption and release. The antibiotic loading method provides a way to switch from rapid and complete to slower and prolonged drug release.