Are mucous retention cysts and pseudocysts in the maxillary sinus a risk factor for dental implants? A systematic review.

BACKGROUND: Mucous retention cysts and pseudocysts of the maxillary sinus are benign lesions present in up to 13% of adult patients. Different surgical approaches for sinus lift and dental implant placement in the presence of these lesions have been proposed. MATERIAL AND METHODS: A systematic review was performed following the PRISMA statement recommendations to answer the PICO question: Does the aspiration or removal of mucous retention cysts/pseudocysts before or during sinus lifting and dental implant placing, affect the survival of the implants? The study was pre-registered in PROSPERO (CRD42020185528). Included articles quality was assessed using the "NIH quality assessment tool" and "The Newcastle-Ottawa scale". RESULTS: Previous literature in this field is scarce and with a low level of evidence. There are no randomized prospective studies. Only 19 studies were identified, being composed of 2 cohort studies and 17 case series/reports. These studies involved 182 patients with a previous history of mucous retention cyst or pseudocyst in 195 maxillary sinuses where 233 implants were placed. The mean age of the patients was 45.5 (range: 12-80 years); 122 (67%) were male patients and 60 (33%) were female patients. The mean follow-up of the patients was 17.6 (range: 4-90 months). Only two fail was reported. No differences were identified in relation to the surgical approach or in relation to the removal/aspiration of the sinus lesion (prior to or simultaneous to sinus grafting) or not. CONCLUSIONS: The level of evidence was grade 4 according to the CEBM and further studies are needed to confirm this observations, but with the available data, dental implants placement after sinus lift procedure in patients with mucous retention cysts and pseudocysts seems to be safe and present high survival regardless on the removal of the lesion or not.

Short dental implants in patients with oral lichen planus: a long-term follow-up.

Oral lichen planus is associated with the Koebner phenomenon, and trauma may exacerbate oral lesions. Short dental implants, as alternatives to bony augmentation, would reduce the number of interventions and their morbidity. However, we know of no studies that have analysed the long-term outcomes of short implants in patients with oral lichen planus. We have therefore designed a retrospective study of such patients treated with short implants (≤8.5mm long), with survival of implants as the main outcome. The secondary outcomes were marginal bone loss and the development of complications. We calculated the implants' survival and compared the outcomes statistically between erosive and reticular oral lichen planus. Sixty-six short implants were placed in 23 patients with a mean (SD) age of 58 (7) years. The mean (SD) peri-implant bone loss was 0.96 (0.89) mm mesially and 0.99 (1.1) mm distally. Sixty-five of the 66 implants survived with a mean (SD) follow-up of 68 (32) months, and there were no significant differences between erosive and reticular disease. Stable long-term outcomes can be expected for short implants placed in patients with oral lichen planus, and graftless rehabilitation of missing teeth could be possible in these patients if short implants were used.

The use of topical corticosteroides in the treatment of oral lichen planus in Spain: A national survey.

BACKGROUND: Explore the treatment of oral lichen planus with topical corticosteroids by the healthcare professionals in Spain. MATERIAL AND METHODS: A questionnaire targeted health professionals who treat OLP, in particular maxillofacial surgeons, dermatologist and dentist. The dissemination of the questionnaires was conducted through professional associations and dental and medical societies. The questionnaire was previously evaluated by means of a cognitive pre-test procedure to ensure that the questions were opportune and appropriate, understandable and accep-table among the professionals. RESULTS: Of the 890 questionnaires sent a total of 190 questionnaires were answered by 90 dentists, 60 dermatologists and 40 by maxillofacial surgeons. The most frequent treatment was 0.1%triamcinolone acetonide in orobase 3 times a day. The effectiveness of the topical corticosteroid treatment was 6.68 (SD= 2.26) in a scale of 1 to 10. The 30% of the dentists and 10.49% of maxillofacial surgeons combined treatment with other drugs. The most frequent one (80%) was nystatin (100,000 IU per millimetre). Dermatologists did not use other treatments in combination with corticosteroids Conclusions: There is a need for national guidelines in treatment for oral lichen planus (treatment criteria, drug, dose, treatment time and method of application of corticosteroid) that can be applied by all professionals who treat this disease.

Silicon calcium phosphate ceramic as novel biomaterial to simulate the bone regenerative properties of autologous bone.

This study was conducted to develop novel ceramic bone substitute that resembles the autologous bone behavior when used as graft material. Solid-state reaction at 1100°C was performed to synthesize ß-tricalcium phosphate (ß-TCP) and biphasic calcium phosphate (BCP). The ceramics were further analyzed to characterize phase composition, microstructural properties, cytocompatability and then challenged to regenerate critical bone defects in the parietal bone of rabbits. X-ray diffraction analysis confirmed the production of ß-TCP and indicated the synthesis of novel BCP composed of ß-TCP and silicocarnotite (calcium phosphate silicate mineral). The cytocompatibility test with human osteoblast cell line revealed enhanced cell proliferation on the BCP ceramic. The novel BCP induced the filling of about 73% of the bone defect with a newly formed bone tissue and an almost complete degradation after 12 weeks of healing. This novel ceramic resembles the autologous bone properties of complete degradation and efficient enhancement of bone formation, making it promising as bone graft material.

Morphogen and proinflammatory cytokine release kinetics from PRGF-Endoret fibrin scaffolds: evaluation of the effect of leukocyte inclusion.

The potential influence of leukocyte incorporation in the kinetic release of growth factors from platelet-rich plasma (PRP) may explain the conflicting efficiency of leukocyte platelet-rich plasma (L-PRP) scaffolds in tissue regeneration. To assess this hypothesis, leukocyte-free (PRGF-Endoret) and L-PRP fibrin scaffolds were prepared, and both morphogen and proinflammatory cytokine release kinetics were analyzed. Clots were incubated with culture medium to monitor protein release over 8 days. Furthermore, the different fibrin scaffolds were morphologically characterized. Results show that leukocyte-free fibrin matrices were homogenous while leukocyte-containing ones were heterogeneous, loose and cellular. Leukocyte incorporation produced a significant increase in the contents of proinflammatory cytokines interleukin (IL)-1ß and IL-16 but not in the platelet-derived growth factors release (<1.5-fold). Surprisingly, the availability of vascular endothelial growth factor suffered an important decrease after 3 days of incubation in the case of L-PRP matrices. While the release of proinflammatory cytokines was almost absent or very low from PRGF-Endoret, the inclusion of leukocytes induced a major increase in these cytokines, which was characterized by the presence of a latent period. The PRGF-Endoret matrices were stable during the 8 days of incubation. The inclusion of leukocytes alters the growth factors release profile and also increased the dose of proinflammatory cytokines.

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.

The effect of hyaluronic acid on brushite cement cohesion.

The improvement of calcium phosphate cement (CPC) cohesion is essential for its application in highly blood perfused regions. This study reports the effectiveness of hyaluronic acids of different molecular weights in the enhancement of brushite cement cohesion. The cement was prepared using a powder phase composed of a mixture of beta-tricalcium phosphate and monocalcium phosphate monohydrate, whereas the liquid phase was formed by 0.5M citric acid solution modified by the addition of hyaluronic acid of different molecular weights. It was found that medium and high molecular weight hyaluronic acid enhances the cement cohesion and scarcely affects the cement mechanical properties. However, concentrations >0.5% (w/v) were less efficient to prevent the cement disintegration. It is concluded that hyaluronic acid could be applied efficiently to reduce brushite cement disintegration.

Combined effect of strontium and pyrophosphate on the properties of brushite cements.

In this study we report the synthesis of strontium-containing brushite cement with good cohesion and a diametral tensile strength (DTS) of 5 MPa. The cement powder, composed of beta-tricalcium phosphate (beta-TCP) and monocalcium phosphate, was adjusted by different concentrations of strontium and pyrophosphate ions. The cement liquid phase was 2M phosphoric acid solution. The cement cohesion and mechanical properties were measured after being aged in water for 24h at 37 degrees C. It was found that at low concentration both strontium and pyrophosphate ions inhibit the cement setting reaction. However, the final setting time was significantly reduced when SrCl2 increased from 5 to 10 wt.% at pyrophosphate concentrations equal to or higher than 2.16 wt.%. The incorporation of strontium ions did not increase the DTS of brushite cements significantly. In contrast, the addition of pyrophosphate ions did increase the DTS of brushite cements significantly. When both ions were added simultaneously, the brushite cement with a Sr2+ content of 5 wt.% had the highest DTS value. Nevertheless, the DTS values of Sr-containing cements were significantly reduced if the pyrophosphate concentration was higher than 2.16 wt.%. The Sr2+ ions had a negative effect on brushite cement cohesion, although the solid weight loss started to decrease at Sr2+ concentrations higher than 5 wt.%.

Beta-tricalcium phosphate release from brushite cement surface.

Different in vivo studies demonstrated that brushite cements are biocompatible, bioresorbable, and osteoconductive. However, the decay of brushite cements has been scarcely studied even though it may be of great concern for clinical applications in highly blood-perfused regions. This work was elaborated to elucidate factors that determine brushite cement surface disintegration. For that, brushite cements were modified using in their preparation different aqueous solutions of phosphoric, glycolic, tartaric, and citric acids in concentrations that were reported to improve the cement properties. Two-viscosity enhancing polysaccharides, chondroitin-4 sulfate and hyaluronic acid, were also assayed. Thereafter, pre- and set cement samples were immersed in distilled water for 24 h. The cement-solid weight loss, microstructure, liquid phase viscosity, mean size of the released particles, and zeta potential were analyzed using X-ray diffraction, FTIR spectroscopy, light scattering, scanning electron microscopy and optical microscopy. It was found that the particles released from the cement surface were beta-TCP, and their amount depends on the carboxylic acid used in the preparation of the cement. The addition of hyaluronic acid and chondroitin-4 sulfate decreased the amount of released particles from the surface of the set brushite cement made with citric acid. Furthermore, the hyaluronic acid increased significantly the viscosity of the citric acid solution and the cement paste prepared with this liquid phase showed a pronounced step down in particle release. In this study, we showed that the water solubility of calcium carboxylate and the viscosity of mixing liquid may dictate the superficial disintegration of brushite cements.