Luca Ramaglia

Profilometric and standard error of the mean analysis of rough implant surfaces treated with different instrumentations.

Purpose:This study evaluated, in vitro, the effects of different instrumentations used in the treatment of peri-implantitis on implant surfaces coated with hydroxyapatite or titanium plasma spray (TPS). Materials and Methods:There were 14 cylindrical rough implants used, including 7 hydroxyapatite and 7 TPS coated. Split in 2 parts for a total of 24 experimental surfaces, implants were treated with a stainless-steel curette, plastic curette, ultrasonic scaler tip, and air-powder-water spray. There was 1 hydroxyapatite and 1 TPS implant used as controls. Profilometry and scanning electron microscopy were used to examine instrumented surfaces for variations in surface topography. Results:All experimental procedures determined changes on tested rough implant surfaces. Such alterations were related to the implant coating material, and the procedure consisting in coating removal and/or leveling of surface roughness. Conclusion:Although a plastic curette and air-powder-water spray induced less implant surface alterations, these instrumentations left deposits on the surface that may affect, in vivo, the tissue healing process.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the osteoblastic differentiation of the human osteosarcoma cell line SaOS-2.

The Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) is a hematopoietic growth factor that regulates the in vitro and in vivo proliferation and differentiation of hematopoietic cells through the interaction with a specific heterodimeric receptor complex (GM-CSFR), consisting of an a and a b chain with molecular weights of 80 and 120 KDa, respectively. We have studied the expression of the GM-CSFR (a chain) on the surface of the human osteosarcoma cell line SaOS-2 and the in vitro effects of different concentrations (10, 100, and 200 ng/ml) of GM-CSF on GM-CSFR expression and the biological activity of SaOS-2 cells. Our data show that SaOS-2 cells express GM-CSFR and that GM-CSF can down-regulate the expression of its own receptor on these cells. Furthermore, to evaluate the biological effects of GM-CSF on SaOS-2 cells, we have investigated cell proliferation and differentiation of these cells treated with different doses of the growth factor through: (1) a morphological analysis of typical osteoblast differentiation markers such as osteopontin and BSP-II; (2) measurement of alkaline phosphatase (ALP) activity; (3) production of bone ECM components (collagen I, fibronectin, tenascin, and laminin); (4) production of interleukin-6 (IL-6) and osteocalcin in the culture medium. The results show that the in vitro treatment of SaOS-2 cells with recombinant human GM-CSF causes a decreased cell proliferation and an increased production of osteopontin, BSP-II, ALP, IL-6, and most but not all ECM components. These findings suggest that GM-CSF can regulate proliferation and differentiation of osteoblast-like SaOS-2 cells and could also play an unexpected role in the maturation of bone tissue.

Different titanium surfaces modulate the bone phenotype of SaOS-2 osteoblast-like cells.

Commercially pure titanium implants presenting a relatively smooth, machined surface or a roughened endosseous surface show a large percentage of clinical success. Surface properties of dental implants seem to affect bone cells response. Implant topography appears to modulate cell growth and differentiation of osteoblasts affecting the bone healing around the titanium implant. The aim of the present study was to examine the effects of 1cm diameter and 1mm thick titanium disks on cellular morphology, adhesion and bone phenotypic expression of human osteoblast-like cells, SaOS-2. SaOS-2 cells were cultured on commercially 1 cm pure titanium disks with three different surface roughness: smooth (S), sandblasted (SB) and titanium plasma sprayed (TPS). Differences in the cellular morphology were found when they were grown on the three different surfaces. An uniform monolayer of cells recovered the S surface, while clusters of multilayered irregularly shaped cells were distributed on the rough SB and TPS surfaces. The adhesion of SaOS-2 cells, as measured after 3h of culture, was not affected by surface roughness. ECM components such as Collagen I (CoI), Fibronectin (FN), Vitronectin (VN) and Tenascin (TN) were secreted and organized only on the SB and TPS surfaces while they remained into the cytoplasm on the S surfaces. Osteopontin and BSP-II were largely detected on the SB and TPS surfaces, while only minimal production was observed on the S ones. These data show that titanium surface roughness affects bone differentiation of osteoblast like-cells, SaOS-2, indicating that surface properties may be able to modulate the osteoblast phenotype. These observations also suggest that the bone healing response around dental implants can be affected by surface topography.

Transglutaminase 2 up-regulation is associated with RANKL/OPG pathway in cultured HPDL cells and THP-1-differentiated macrophages

Recent evidence emphasized that transglutaminase 2 (TG2), a protein cross-linking enzyme, may play a role in the early phase of inflammation. High levels of TG2 have been associated with the constitutive activation of nuclear factor-kappa B (NF-κB) that is considered the main regulator of inflammation. In this context, the receptor activator of NF-kappa B ligand (RANKL) and receptor activator of NF-κB have extensive functions in the regulation of cytokine secretion associated with different pathological conditions. The human periodontal ligament (HPDL) cells, which express and secrete osteoprotegerin (OPG) and RANKL, represent an useful “ex vivo” model for monitoring cell response in inflammatory microenvironments, such as periodontitis-dependent tissue response. Thus, we evaluated TG2 expression and alterations in RANKL/OPG ratio occurring in cultured HPDL cells. The HPDL cells were obtained from patients with chronic periodontitis (CP) and healthy subjects. We observed the up-regulation of some inflammatory markers, such as IL-6, TNF-α, and HMGB-1, and at the same time an increase in TG2 mRNA levels in HPDL cells from CP patients compared with healthy subjects. We found a positive correlation between RANKL/OPG ratio and TG2 mRNA levels in HPDL cells from CP patients. In the parallel experiments, we demonstrated that TG2 inhibition reduced RANKL expression in both HPDL cells from CP patients and monocytes differentiated to macrophages by tetradecanoyl phorbol acetate treatment. Given the RANKL key role in NF-κB pathway and the observed up-regulation of pro-inflammatory cytokines, our data suggest that TG2 may be involved in molecular mechanisms of inflammatory response occurring in periodontal disease.

Five-year outcome of bone remodelling around implants in the maxillary sinus: assessment of differences between implants placed in autogenous inlay bone blocks and in ungrafted maxilla.

The placement of implants in the posterior maxillary area is considered a reliable procedure, offering recognized rehabilitative advantages. The aim of this study was to evaluate the performance of dental implants placed in the sinus floor augmented with a block autograft by comparing the outcomes over 5 years with those of dental implants positioned in non-augmented bone. This retrospective cohort study included 16 patients who had undergone prosthetic rehabilitation supported by dental implants between 2000 and 2006. One implant per patient was included and assigned to one of two predictor groups: grafted versus ungrafted maxillary sinus. Changes in marginal bone level (MBL) and apical bone level (ABL) over time, at 1, 3, and 5 years, were the primary outcome variables. Appropriate pair-wise comparison tests were performed. No significant differences were seen with regard to ABLs and among times between the grafted group (nine implants) and the ungrafted group (seven implants). Significant marginal bone resorption was found over time, primarily at the buccal aspect, in both study groups. The bone surrounding the apex of dental implants appeared stable after sinus augmentation in the grafted area. The behaviour of the two groups with regard to loss of MBLs over time was very similar.

The effect of a functional appliance in the management of temporomandibular joint disorders in patients with juvenile idiopathic arthritis.

BACKGROUND Patients affected by juvenile idiopathic arthritis (JIA) may have several craniofacial growth disturbances and involvements at the temporomandibular joint (TMJ). The objectives of the present study were to evaluate the clinical effectiveness of functional therapy used to reduce asymmetry of mandibular growth and TMJ disorder in patients with JIA. METHODS By a retrospective longitudinal design, a cohort of 54 patients with JIA (mean age, 13.2±3.7 years; range, 5-17.7 years) and with TMJ involvements was enrolled in the study. Each patient, following the collection of clinical parameters, was treated for 24 months with a functional appliance individually customized by acrylic resin and resilient stainless steel with posterior and anterior metallic bite planes preventing the teeth from intercuspal contact. To evaluate differences before (T0) and after therapy (T1) of the clinical TMJ parameters, the statistical analysis by the χ2 Test was performed. RESULTS All the patients completed successfully the study. In patients with JIA, the use of a functional appliance determined a statistically significant difference of the pain during jaw movement, maximal mouth opening, TMJ sounds and crepitations (P<0.001) and TMJ click, significantly reduced at T1 (P<0.05). CONCLUSIONS The use of an orthodontic functional appliance determined a significant improvement, at 24 months, in many TMJ signs and symptoms in patients affected by JIA and with TMJ disorders. This study suggests that children and adolescents with JIA which presented either unilateral or bilateral moderate to severe TMJ involvement, if not treated, should be develop severe disturbances during growing.

Implant angulation: 2-year retrospective analysis on the influence of dental implant angle insertion on marginal bone resorption in maxillary and mandibular osseous onlay grafts.

ObjectivesThe purpose of this study was to determine the existence of correlations between marginal peri-implant linear bone loss and the angulation of implants in maxillary and mandibular augmented areas over the course of a 2-year survey.Materials and methodsDependent variables described the sample of the present retrospective chart review. By using three-dimensional radiographs, input variables, describing the implant angulation (buccal–lingual angle [φ] and mesial–distal angle [θ]) were measured; outcome variables described survival rate and marginal bone resorption (MBR) around dental implants in autogenous grafts (10 maxillae and 14 mandibles). Pairwise comparisons and linear correlation coefficient were computed.ResultsThe peri-implant MBR in maxillary buccal and palatal areas appeared less intensive in the presence of an increased angulation of an implant towards the palatal side. Minor MBR was recorded around mandibular dental implants positioned at a right angle and slightly angulated towards the mesial.ConclusionsResorption in buccal areas may be less intensive as the angulation of placed implants increases towards the palatal area in the maxilla, whereas for the mandible, a greater inclination towards the lingual area could be negative. In the mandibular group, when the implant was slightly angulated in the direction of the distal area, bone resorption seemed to be more marked in the buccal area.Clinical relevanceIn the planning of dental implant placement in reconstructed alveolar bone with autograft, the extremely unfavourable resorption at the buccal aspect should be considered; this marginal bone loss seemed to be very sensitive to the angulation of the dental implant.

Stage-specific therapeutic strategies of medication-related osteonecrosis of the jaws: a systematic review and meta-analysis of the drug suspension protocol

ObjectiveThe most debated topic about medication-related osteonecrosis of the jaws (MRONJ) is its therapy, as there are no definitive guidelines. The aims of this systematic review were (a) to outline the best therapeutic approach according to the stage at diagnosis and (b) to perform a meta-analysis to assess whether the drug-holiday protocol may be or not an effective method in the management of MRONJ patients.Materials and methodsThe systematic review was performed following the PRISMA principles. Results were screened according to inclusion and exclusion criteria regarding staging before/after treatment, follow-up, and information provided by the authors. For statistical analysis, linear variables are reported as means and standard deviations, medians, and inter-quartile range (IQR); normality of data, according to the distribution of complete healing (primary outcome variable), was assessed with the Kolmogorov-Smirnov test. A p value < 0.05 was considered statistically significant for all tests.ResultsThirteen studies were selected out of 1480. None of them was case-controlled or randomized. Conservative approach showed good results at early stages, but heterogeneous result at advanced stages (100% stage 0, stage I range 81–97%, stage II range 63.6–100%, stage III 73%). Surgical approach showed heterogeneous results at all stages (stage I range 0–100%, stage II range 52–100%, stage III range 50–100%). Statistical analysis showed a significantly higher prevalence of completely healed sites in patients who followed the drug-holiday protocol.ConclusionsThe results suggest that the current stage-specific approach for MRONJ therapy is based on a sound clinical rationale. Conservative treatment appears to yield better outcomes at early stages, while further investigations are needed to elucidate the best protocols for the management of advanced stages. The drug-holiday protocol statistically promotes complete healing after oral surgery procedures but the application should be dictated by the condition of each patient.Clinical relevanceAt present, early MRONJ stages should be primarily treated by means of a conservative approach while more advanced stages must be carefully evaluated. Individual decisions should be made for every single case even with respect to the drug-holiday protocol.

A 5-Year Implant Follow-Up in Maxillary and Mandibular Horizontal Osseous Onlay Grafts and Native Bone

The purpose of this study is to analyze marginal bone levels (MBLs) around dental implants positioned in the upper and lower jaw with or without horizontal onlay grafting procedures, and to survey implant survival with a follow-up of 5 years. Seventeen patients were surveyed in the present retrospective chart review. A total of 27 dental implants positioned in pristine bone and 21 in horizontally grafted bone were enrolled. MBLs were recorded for 4 aspects during a radiologic survey of 5 years. Significant differences were searched for among times and surgical procedures with paired and unpaired comparison tests, respectively, and survival rates were calculated for the 2 groups. In the maxilla, no statistically-significant differences between pristine and augmented groups were obtained; the time comparisons for pristine implants showed an affection of palatal, mesial, and distal sides, whereas the resorption around implants placed into horizontally grafted bone of anterior maxilla seemed to be limited just to buccal and distal aspects. Comparisons with the pristine horizontal procedure revealed that just the buccal sides were involved. The analysis of time comparisons attested to a continuous alveolar bone remodeling during the entire time of the survey for the pristine group. Given the extremely unfavorable resorption at the buccal aspect of the augmented areas, clinicians should reserve dental implant positioning into horizontal bone graft to selected patients, in whom it may represent one of the last opportunities of rehabilitation with a fixed prosthesis.

Implantology and Periodontal Disease: The Panacea to Problem Solving?

Introduction: The specialty of periodontology has changed dramatically in recent years. With the long-standing goal of retaining teeth in a functional and esthetical state, the periodontology has developed a high level of expertise in the regeneration of bone and connective tissues that support the teeth. However, periodontists have also joined maxillofacial surgeons as the primary providers of implant surgery. Methods: The tremendous innovations of periodontists induced also by the marketplace resulted in predictable periodontal treatment outcomes for most patients by the implants led to a dramatically different marketplace in which many patients with periodontitis can be treated by the implants rather than the traditional periodontal treatment. Results: The aim of this article is to focus on the innovator’s dilemma for periodontists today is that key elements of our rewarding contributions to dentistry in recent decades are unlikely to be part of a strong and rewarding future for the profession. Conclusions: With the intriguing role of the personalized medicine approach that integrates genomic and clinical information to predict a possible predisposition, we do not suggest a reduced role for periodontists in dental implant surgery but rather a more prominent role in complex cases to achieve surgical implant needs and proper reconstruction and long-term maintenance of the patient’s health.