Is alveolar ridge preservation an overtreatment?

The morphology and dimensions of the postextraction alveolar ridge are important for the surgical and restorative phases of implant treatment. Adequate new bone formation and preservation of alveolar ridge dimensions following extraction will facilitate installation of the implant in a restorative position, while preservation of soft tissue contour and volume is essential for an aesthetic and implant-supported restoration with healthy peri-implant tissues. Alveolar ridge preservation (ARP) refers to any procedure that aims to: (i) limit dimensional changes in the alveolar ridge after extraction facilitating implant placement without additional extensive bone and soft tissue augmentation procedures (ii) promote new bone formation in the healing alveolus, and (iii) promote soft tissue healing at the entrance of the alveolus and preserve the alveolar ridge contour. Although ARP is a clinically validated and safe approach, in certain clinical scenarios, the additional clinical benefit of ARP over unassisted socket healing has been debated and it appears that for some clinicians may represent an overtreatment. The aim of this critical review was to discuss the evidence pertaining to the four key objectives of ARP and to determine where ARP can lead to favorable outcomes when compared to unassisted socket healing.

Alveolar ridge preservation with guided bone regeneration or socket seal technique. A randomised, single-blind controlled clinical trial.

OBJECTIVES: To compare radiographic bone changes, following alveolar ridge preservation (ARP) using Guided Bone Regeneration (GBR), a Socket Seal (SS) technique or unassisted socket healing (Control). MATERIAL AND METHODS: Patients requiring a single rooted tooth extraction in the anterior maxilla, were randomly allocated into: GBR, SS and Control groups (n= 14/). Cone Beam Computed Tomography (CBCT) images were recorded post-extraction and at 4 months, the mid-buccal and mid-palatal alveolar ridge heights (BARH/PARH) were measured. The alveolar ridge width, cross-sectional socket and alveolar-process area changes, implant placement feasibility, requirement for bone augmentation and post-surgical complications were also recorded. RESULTS: BARH and PARH was found to increase with the SS (0.65 mm ± 1.1/0.65 mm ± 1.42) techniques, stabilise with GBR (0.07 mm ± 0.83/0.86 mm ±1.37) and decrease in the Control (-0.52 mm ± 0.8/-0.43 mm ± 0.83). Statistically significance was found when comparing the GBR and SS BARH (p = .04/.005) and GBR PARH (p = .02) against the Control. GBR recorded the smallest reduction in alveolar ridge width (-2.17 mm ± 0.84), when compared to the Control (-2.3 mm ± 1.11) (p = .89). A mid-socket cross-sectional area reduction of 4% (-2.27 mm2  ± 11.89), 1% (-0.88 mm2  ± 15.48) and 13% (-6.93 mm2  ± 8.22) was found with GBR, SS and Control groups (GBR vs. Control p = .01). The equivalent alveolar process area reduction was 8% (-7.36 mm2  ± 10.45), 6% (-7 mm2  ± 18.97) and 11% (-11.32 mm2  ± 10.92). All groups supported implant placement, with bone dehiscence noted in 57% (n = 4), 64%(n = 7) and 85%(n = 12) of GBR, SS and Control cases (GBR vs. Control p = .03). GBR had a higher risk of swelling and mucosal colour change, with SS associated with graft sequestration and matrix breakdown. CONCLUSION: GBR ARP was found to be more effective at reducing radiographic bone dimensional changes following tooth extraction.

Comparison of clinical outcomes of immediate versus delayed placement of dental implants: A systematic review and meta-analysis.

OBJECTIVE: Two focused questions were addressed: Focused question (Q1) 1) Are there any differences between immediate and delayed placement in terms of (i) survival rate, (ii) success rate, (iii) radiographic marginal bone levels, (iv) height/(v)thickness of buccal wall, (vi) peri-implant mucosal margin position, (vii) aesthetics outcomes and (viii) patient reported outcomes? Focused question 2 (Q2) What is the estimated effect size of immediate implant placement for all parameters included in Q1? MATERIALS AND METHODS: An electronic search (MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials and OpenGray) and hand search were conducted up to November 2019. Randomised controlled trials (RCT) with delayed implant placement as controls were eligible in the analysis for Q1. Immediate dental implant arms RCTs, controlled clinical trials (CCTs) and prospective case series of immediate implant placement were eligible in the analysis for Q2. RESULTS: Six papers (RCTs) were included in the analysis for Q1 and 53 papers (22 RCTs, 11 CCTs and 20 case series) for Q2. Q1: Meta-analyses did not show any significant difference in implant survival, but it did for bone levels and PES scores at 1 year post-loading, favouring the immediate group. Q2: Meta-analyses showed that immediate implants had a high survival rate (97%) and presented high PES scores (range 10.36 to 11.25). Information regarding marginal bone loss and gingival/papillary recession varied among all included studies. CONCLUSION: Similar survival rate was found between immediate and delayed implants. Immediate implants presented threefold early complications and twofold delayed complications. Success criteria should be reported more consistently, and the incidence/type of complications associated with immediate implants should be further explored.

The Effect of Microcosm Biofilm Decontamination on Surface Topography, Chemistry, and Biocompatibility Dynamics of Implant Titanium Surfaces.

Since the inception of dental implants, a steadily increasing prevalence of peri-implantitis has been documented. Irrespective of the treatment protocol applied for the management of peri-implantitis, this biofilm-associated pathology, continues to be a clinical challenge yielding unpredictable and variable levels of resolution, and in some cases resulting in implant loss. This paper investigated the effect of microcosm biofilm in vitro decontamination on surface topography, wettability, chemistry, and biocompatibility, following decontamination protocols applied to previously infected implant titanium (Ti) surfaces, both micro-rough -Sandblasted, Large-grit, Acid-etched (SLA)-and smooth surfaces -Machined (M). Microcosm biofilms were grown on SLA and M Ti discs. These were treated with TiBrushes (TiB), combination of TiB and photodynamic therapy (PDT), combination of TiB and 0.2%CHX/1%NaClO, plus or minus Ultraviolet-C (UV-C) radiation. Surface topography was evaluated by Scanning Electron Microscopy (SEM) and Laser Surface Profilometry. Surface function was analysed through wettability analysis. Surface chemistry evaluation of the discs was performed under SEM/Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). Biocompatibility was tested with the cytocompatibility assay using human osteoblast-like osteosarcoma cell line (MG-63) cells. Elemental analysis of the discs disclosed chemical surface alterations resulting from the different treatment modalities. Titanium, carbon, oxygen, sodium, aluminium, silver, were identified by EDX as the main components of all the discs. Based on the data drawn from this study, we have shown that following the decontamination of Ti surfaces the biomaterial surface chemistry and topography was altered. The type of treatment and Ti surface had a significant effect on cytocompatibility (p = 0.0001). Although, no treatment modality hindered the titanium surface biocompatibility, parameters such as the use of chemical agents and micro-rough surfaces had a higher cytotoxic effect in MG-63 cells. The use of smooth surfaces, and photofunctionalisation of the TiO2 layer had a beneficial effect on cytocompatibility following decontamination.

The role of strontium ranelate and guided bone regeneration in osteoporotic and healthy conditions.

BACKGROUND/ OBJECTIVES: SR is a chemical agent developed for the treatment of osteoporosis. In vitro, SR enhanced replication of osteoprogenitor cells and bone formation. In vivo, in ovariectomized rats SR prevented the biomechanical deterioration of bone while in non-ovariectomized rats, enhanced bone architecture and increased trabecular and cortical bone mass. The aim of this study was to evaluate the effect of SR on bone healing of calvarial critical size defects treated with a deproteinized bovine bone mineral (DBBM) and a collagen barrier (CM), in healthy and osteoporotic rats. MATERIAL AND METHODS: Sixty-four, 4-month-old Wistar female rats were used. Osteoporosis was induced by ovariectomy and calcium-deficient diet in half of them. Sixteen ovariectomized (OSR) and 16 healthy (HSR) rats were treated with SR while no medication was administered in the remaining 16 healthy (H) and 16 ovariectomized (O) rats. At 6 weeks after ovariectomy, a 5mm defect was created in each parietal bone of every animal. One defect was treated with DBBM and CM, while the contralateral was left untreated. Qualitative and quantitative histological analysis was performed at 30 and 60 days of healing. A generalized estimating equations test was performed to evaluate the effect of SR and osteoporosis, on new bone formation (NB). RESULTS: After 30 days of healing, NB in the untreated defects was 3.4%±1.7%, 4.3%±6.2%, 3.2±4.5%, 15.9±23.5% in O, OSR, H and HSR groups, respectively; after 60 days, NB was 4.7%±4.3%, 11.3%±7%, 7.1%±13.2, 12.1%±13.5%, respectively. In the GBR-treated defects, after 30 days, NB was 2.6%±1.4%, 2.4%±1.6%, 4.5%±4.1%, 10.3%±14.4% in O, OSR, H and HSR groups, respectively; after 60 days, NB was 2.2%±1.6%, 4.3%±4.2%, 7%±5.1%, 10.8%±17.4%, respectively. Osteoporosis (p=0.008) and the absence of strontium ranelate treatment (p=0.01) had a negative impact on NB. CONCLUSION: SR may promote bone formation in calvarial defects in healthy and osteoporotic rats, albeit in a moderate extent.

Immediate implant placement in fresh alveolar sockets with a minimal split-thickness envelope flap: A randomised controlled clinical trial.

OBJECTIVES: Comparing PES/WES scores, modified success rate, survival, success, buccal bone thickness and patient-reported outcomes of immediate dental implants placed in fresh alveolar sockets using a flap or a minimal split-thickness envelope flap (MSTEF). MATERIALS AND METHODS: Implants following random assignment into a flap or MSTEF group were placed immediately in anterior and premolar areas. Guided bone regeneration and autogenous connective tissue graft were used in all cases. A temporary prosthesis was provided followed by the final prosthesis at 16-18 weeks. Success and survival rates together with radiographic buccal bone thickness and patient satisfaction were evaluated at 12-month post-loading. The aesthetic outcome was evaluated through the Pink (PES) and White (WES) Aesthetic Score by 8 blind clinicians of different training background and incorporated in modified success criteria. RESULTS: 28 implants were placed on 28 patients. No statistically significant differences were noted in PES (10.54 control versus 10.80 test), WES scores (6.97 control versus 6.95 test) or success criteria including aesthetic parameters (modified success criteria) for the different specialty groups (Range 69%-92%). In addition, no statistically significant differences were noted in survival (100%), success (100%), buccal wall thickness between control (0.72 ± 0.22) and test group (0.92 ± 0.31) and patients' reported outcomes. CONCLUSIONS: Immediate dental implant treatment with flap/ MSTEF provided similar mean PES/WES scores, modified success rate, survival, mean buccal bone levels and patients' satisfaction. However, aesthetic failures were common in both groups.

Immediate provisionalization of bone level implants with a hydrophilic surface. A five-year follow-up of a randomized controlled clinical trial.

OBJECTIVES: To follow-up the radiographic bone level changes and the clinical outcomes of immediately provisionalized and conventionally restored implants with a hydrophilic surface following 5 years of function. MATERIALS AND METHODS: This was a 5-year follow-up of a prospective, randomized, single-blind controlled study involving 16 of the 24 originally recruited patients in need of a single-tooth replacement in the esthetic area. Implants were either immediately provisionalized with a non-occluding temporary crown (test group, n = 7), or left without a crown (control group, n = 9). In both groups, the definitive restoration was placed 16 weeks after implant placement. Radiographic and clinical parameters were evaluated at 36, 48, and 60 months post-implant placement, together with implant survival and success rates. The esthetic outcomes were measured with the Papilla Fill Index (PFI) and the Pink Esthetic Score (PES). RESULTS: At 60 months, similar peri-implant bone loss was observed in the test (-0.42 mm ±0.17 mm) and in the control (-0.37 mm ±0.35 mm) groups. A tendency for an improved esthetic outcome from implant loading to the subsequent follow-ups was noticed in both groups. Both groups presented with high levels of long-term implant survival and success. CONCLUSIONS: This study supports non-functional immediate provisionalization as a viable long-term option for the management of single-tooth implants in the esthetic area. However, the small sample size does not allow statistical inference at 60 months of follow-up and future adequately powered studies are warranted.

The role of immediate provisional restorations on implants with a hydrophilic surface: A randomised, single-blind controlled clinical trial.

OBJECTIVES: To compare the radiographic bone changes, clinical parameters and aesthetic outcomes of immediately provisionalised and conventionally restored implants at 12- and 24-months post-implant placement. MATERIAL AND METHODS: In 24 patients, 24 bone level implants with a hydrophilic (SLActive) surface were placed in healed sites and they were either immediately provisionalised with a non-occluding temporary crown (test group) or left without a crown (control group). In both groups, the definitive restoration was placed 16 weeks after implant placement. Clinical and radiographic parameters were calculated at 12- and 24-months post-implant placement, together with implant success/survival rates according to three different sets of criteria. The aesthetic outcome was evaluated through the Papilla Fill Index and the Pink Aesthetic Score. RESULTS: The mean marginal bone loss at 1 year was -0.73 mm (SD 0.83 mm) in the test group and -0.22 mm (SD 0.46 mm) in the control group (p > .05). Whilst 100% survival rate and positive aesthetic outcomes were recorded in both groups, three patients of the test group did not fulfil all success criteria. CONCLUSIONS: Immediate provisionalisation may represent a viable option for the replacement of single missing teeth, with radiographic, clinical and aesthetic results comparable to those of conventionally loaded implants at 2 years of follow-up.

Group 1 ITI Consensus Report: The influence of implant length and design and medications on clinical and patient-reported outcomes.

OBJECTIVES: The aim of Working Group 1 was to address the influence of different local (implant length, diameter, and design) and systemic (medications) factors on clinical, radiographic, and patient-reported outcomes in implant dentistry. Focused questions on (a) short posterior dental implants (≤6 mm), (b) narrow diameter implants, (c) implant design (tapered compared to a non-tapered implant design), and (d) medication-related dental implant failures were addressed. MATERIALS AND METHODS: Four systematic reviews were prepared in advance of the Consensus Conference and were discussed among the participants of Group 1. Consensus statements, clinical recommendations, and recommendations for future research were based on structured group discussions until consensus was reached among the entire expert Group 1. The statements were then presented and accepted following further discussion and modifications as required by the plenary. RESULTS: Short implants (≤6 mm) revealed a survival rate ranging from 86.7% to 100%, whereas standard implant survival rate ranged from 95% to 100% with a follow-up from 1 to 5 years. Short implants demonstrated a higher variability and a higher Risk Ratio [RR: 1.24 (95% CI: 0.63, 2.44, p = 0.54)] for failure compared to standard implants. Narrow diameter implants (NDI) have been classified into three categories: Category 1: Implants with a diameter of <2.5 mm ("Mini-implants"); Category 2: Implants with a diameter of 2.5 mm to <3.3 mm; Category 3: Implants with a diameter of 3.3 mm to 3.5 mm. Mean survival rates were 94.7 ± 5%, 97.3 ± 5% and 97.7 ± 2.3% for category 1, 2 and 3. Tapered versus non-tapered implants demonstrated only insignificant differences regarding clinical, radiographic, and patient-reported outcomes. The intake of certain selective serotonin reuptake inhibitors and proton pump inhibitors is associated with a statistically significant increased implant failure rate. The intake of bisphosphonates related to the treatment of osteoporosis was not associated with an increased implant failure rate. CONCLUSIONS: It is concluded that short implants (≤6 mm) are a valid option in situations of reduced bone height to avoid possible morbidity associated with augmentation procedures; however, they reveal a higher variability and lower predictability in survival rates. Narrow diameter implants with diameters of 2.5 mm and more demonstrated no difference in implant survival rates compared to standard diameter implants. In contrast, it is concluded that narrow diameter implants with diameters of less than 2.5 mm exhibited lower survival rates compared to standard diameter implants. It is further concluded that there are no differences between tapered versus non-tapered dental implants. Certain medications such as selective serotonin reuptake inhibitors and proton pump inhibitors showed an association with a higher implant failure rate.

Hard and soft tissue changes following alveolar ridge preservation: a systematic review.

OBJECTIVE: Two focused questions were addressed within this systematic review. Q1) What is the effect of alveolar ridge preservation on linear and volumetric alveolar site dimensions, keratinised measurements, histological characteristics and patient-based outcomes when compared to unassisted socket healing. Q2) What is the size effect of these outcomes in three different types of intervention (guided bone regeneration, socket grafting and socket seal). MATERIALS AND METHODS: An electronic search (MEDLINE, EMBASE, Cochrane Central Register LILACS, Web of Science) and hand-search was conducted up to June 2015. Randomised controlled trials (RCT) and controlled clinical trials (CCT); with unassisted socket healing as controls: were eligible in the analysis for Q1. RCTs, CCTs and large prospective case series with or without an unassisted socket healing as control group were eligible in the analysis for Q2. RESULTS: Nine papers (8 RCTs and 1 CCTs) were included in the analysis for Q1 and 37 papers (29 RCTs, 7 CCTs and 1 case series) for Q2. The risk for bias was unclear or high in most of the studies. Q1: the standardised mean difference (SMD) in vertical mid-buccal bone height between ARP and a non-treated site was 0.739 mm (95% CI: 0.332 to 1.147). The SMD when proximal vertical bone height and horizontal bone width was compared was 0.796mm (95% CI: -1.228 to 0.364) and 1.198 mm (95% CI: -0.0374 to 2.433). Examination of ARP sites revealed significant variation in vital and trabecular bone percentages and keratinised tissue width and thickness. Adverse events were routinely reported, with three papers reporting a high level of complications in the test and control groups and two papers reporting greater risks associated with ARP. No studies reported on variables associated with the patient experience in either the test or the control group. Q2: A pooled effect reduction (PER) in mid-buccal alveolar ridge height of -0.467 mm (95% CI: -0.866 to -0.069) was recorded for GBR procedures and -0.157 mm (95% CI: -0.554 to 0.239) for socket grafting. A proximal vertical bone height reduction of -0.356 mm (95% CI: -0.490 to -0.222) was recorded for GBR, with a horizontal dimensional reduction of -1.45 mm (95% CI: -1.892 to -1.008) measured following GBR and -1.613 mm (95% CI: -1.989 to -1.238) for socket grafting procedures. Five papers reported on histological findings after ARP. Two papers indicated an increase in the width of the keratinised tissue following GBR, with two papers reporting a reduction in the thickness of the keratinised tissue following GBR. Histological examination revealed extensive variations in the treatment protocols and biomaterials materials used to evaluate extraction socket healing. GBR studies reported a variation in total bone formation of 47.9 ± 9.1% to 24.67 ± 15.92%. Post-operative complications were reported by 29 papers, with the most common findings soft tissue inflammation and infection. CONCLUSION: ARP results in a significant reduction in the vertical bone dimensional change following tooth extraction when compared to unassisted socket healing. The reduction in horizontal alveolar bone dimensional change was found to be variable. No evidence was identified to clearly indicate the superior impact of a type of ARP intervention (GBR, socket filler and socket seal) on bone dimensional preservation, bone formation, keratinised tissue dimensions and patient complications.

Peri-implant and periodontal microbiome diversity in aggressive periodontitis patients: a pilot study.

AIM: To investigate the bacterial microbiome in periodontal and peri-implant biofilms deriving from aggressive periodontitis patients (AgP) in conditions of health and disease. MATERIAL AND METHODS: Ninety-one plaque samples were collected from 18 patients previously diagnosed and treated for AgP. The samples were taken from (i) 24 residual periodontal pockets (TD) (n = 6 patients), (ii) 24 healthy periodontal sites (TH) (n = 6 patients), (iii) 24 dental sites from the same implant patients (TM) (n = 6 patients), (iv) 5 peri-implantitis sites (II) (n = 2 patients), (v) 6 peri-mucositis sites (IM) (n = 2 patients) and (vi) 8 healthy implant sites (IH) (n = 2 patients). All subjects underwent periodontal clinical and radiographic assessments. Bacterial DNA was extracted, PCR amplified using 16S rRNA gene V5-V7 primers (barcoded amplicons 785F;1175R), purified, pooled at equimolar concentrations and sequenced (MiSeq, Illumina) yielding 250 bp paired-end reads. The 16S rRNA reads were filtered, assembled and analysed. RESULTS: The genera Propionibacterium, Paludibacter, Staphylococcus, Filifactor, Mogibacterium, Bradyrhizobium and Acinetobacter were unique to peri-implant sites (P = 0.05). In TM samples, different proportions and bacterial spp. were found when compared with the same patients' samples at implant sites. Specifically, Actinomyces (P = 0.013) and Corynebacterium (P = 0.030) genera showed to be significantly more abundant in the TM group when compared to the II. The highest phylogenetic diversity was observed in residual periodontal pocket sites (TD). Increased annual tooth loss rate and residual pocketing was related to high proportions of the genera Actinomyces, Porphyromonas, Prevotella, Streptococcus, Actinomycetaceae, TM7-3, Selenomonas, and Dialister, Treponema, Parvimonas and Peptostreptococcus in the TD group. CONCLUSION: Within the limitations of this pilot study, the periodontal and peri-implant microbiome presents a dissimilar taxonomic composition across different niches within AgP patients. The host response, the habitat structure and the vast coexistence of strains and species surrounding implants and teeth in health and disease are likely to be shaping the heterogeneous composition of the subgingival biofilms. The TM7 phylum was found only in TD cases. The investigation of the impact of periodontal and peri-implant keystone species on these complex ecosystems in states of health and disease seems to be essential.

The effect of experimental osteoporosis on bone regeneration: Part 1, histology findings.

OBJECTIVES: To histologically define the healing events occurring in calvarial critical size defects (CSDs) following treatment with a collagen barrier for guided bone regeneration (GBR) and a particulate graft in healthy and osteoporotic conditions. MATERIAL AND METHODS: Thirty-six 10-month-old, female, Wistar rats were used in this study. Half of them were ovariectomized (OVX) and fed with a low-calcium diet to induce an osteoporotic-like status. In each animal of both groups, two 5-mm CSDs were created, one in the centre of each parietal bone, and they were treated with a deproteinized bovine bone mineral (DBBM) particulate graft and a bi-layer collagen membrane. Six OVX and six healthy control rats were randomly euthanized at 7, 14 and 30 days. One defect per animal was randomly processed for decalcified histology. Three central sections were used for qualitative histology and histomorphometric analysis. RESULTS: No significant difference in terms of percentage of newly formed bone was detected between the two groups at the different healing periods. However, a trend towards less bone formation and of poorer quality, expressed as reduced bone maturation, was detected in the OVX animals at 30 days. DISCUSSION: According to this study, GBR with a collagen barrier and a DBBM graft can be successfully obtained also in osteoporotic-like conditions. Future studies considering longer healing periods and controlling for the confounding factors arising from the use of a particulate graft are needed to confirm these data.

Guided bone regeneration in osteoporotic conditions following treatment with zoledronic acid.

OBJECTIVES: To evaluate new bone formation in calvarial critical size defects (CSD) under dense polytetrafluoroethylene (d-PTFE), microporous membranes for guided bone regeneration (GBR) in healthy, osteoporotic and osteoporotic treated with zoledronic acid (ZA) rats. METHODS: Forty-eight, female, 6-month old Wistar rats were included in the study. Osteoporosis was induced by ovariectomy (OVX) and calcium-deficient diet in 32 rats. Sixteen OVX rats were treated with a single dose of Zolendronic Acid (ZA) (OZ), while 16 OVX rats received no treatment (O). The remaining 16 rats were sham-operated and used as healthy controls (C). At 6 weeks following osteoporosis induction, two 5 mm CSD were created in the parietal bones and one of them was treated with a double d-PTFE membrane. The healing periods were 30 and 60 days. New bone formation (NB) was assessed by qualitative and quantitative histological analysis. RESULTS: After 30 days of healing, NB (mean% (95% CI)) was 78.9% (21), 93.1% (9.3) and 84.2% (26.9) in the membrane treated defects and 18.8% (24.1), 27.1% (7.9) and 31% (38.8) in the untreated defects of group O, OZ and C, respectively. After 60 days of healing, NB was 78.3% (14.4), 95.8% (9) and 90.1% (26.1) in the membrane treated defects and 10.8% (17.4), 51.6% (39.4) and 15.7% (12.1) in the untreated defects of group O, OZ and C, respectively. Hierarchical analysis of variance showed that treatment with ZA (P = 0.001) and the use of membrane (P = 0.000) significantly increased new bone formation while presence of osteoporosis may have reduced new bone formation (P = 0.028). CONCLUSION: d-PTFE membranes for GBR promote bone healing in osteoporotic and healthy rats. Treatment with ZA may improve new bone formation in osteoporotic rats.

Experimental models for contamination of titanium surfaces and disinfection protocols.

AIM: The aim of this pilot study was to describe an in vitro model of peri-implantitis microcosm for contamination of titanium surfaces and an in vivo model for evaluating different disinfection strategies of titanium surfaces. MATERIALS AND METHODS: Biofilms were grown in vitro for 30 days on sandblasted large-grit acid-etched (SLA) Ti discs (n = 69) in a constant depth film fermentor (CDFF) associated with peri-implantitis conditions. Four Swedish loop rabbits were randomly allocated in three test groups (T1 , T2 , T3 ) and one control group (C). In group C, two sterile SLA Ti discs were implanted/fixed in each tibia. In the test groups (to evaluate the potential of different surface disinfection techniques), one sterile and three previously disinfected SLA Ti discs were placed following different disinfection protocols: group T1 : the discs were treated with a titanium brush - TiB; group T2 : the discs were treated with the combination of TiB and photodynamic therapy; and group T3 : the discs were treated with TiB and 1%NaOCl plus 0.2%CHX. Tensile strength test and qualitative histological analysis were performed on all 16 discs after 4 weeks of healing. RESULTS: Thirty days following CDFF emulating peri-implantitis microcosm, all SLA Ti discs had a mean total viable aerobes and facultative anaerobes count of 8.06 log10  CFU/biofilm and anaerobes 8.32 log10  CFU/biofilm. Before implantation/fixation on the tibia, differences of log10  CFU/biofilm counts between control and test groups after post hoc adjustment were highly significant (P < 0.001). In the in vivo analysis, group C exhibited the highest tensile strength (67.60 N [25.64-127.02]) and the histological sections revealed the presence of dense mature bone in direct contact with the disc surface. The analysis at the test groups showed that T2 presented with the highest tensile strength in comparison with the other two test groups. CONCLUSIONS: The in vitro model used in this study provides a valuable and reproducible tool for evaluating the in vitro dynamics of the peri-implantitis microcosm biofilm and for contaminating in a reproducible manner titanium surfaces. At the same time, the in vivo model used in this study provides a standardised mode of evaluating disinfection modalities of previously infected titanium surfaces.

A systematic review on the correlation between skeletal and jawbone mineral density in osteoporotic subjects.

OBJECTIVES: The aim of this systematic review was to assess whether the systemic skeletal reduction of bone mineral density (BMD) that characterizes osteoporotic subjects is also associated with a reduction of BMD in the jawbones. MATERIAL AND METHODS: Two reviewers searched independently and in duplicate three databases up to May 2014 and assessed the risk of bias using a tailored version of the Newcastle-Ottawa scale (NOS). Only papers reporting either Pearson's correlation coefficient or Spearman's rank correlation coefficient between skeletal and jawbone mineral density in more than five osteoporotic subjects were selected. RESULTS: From 1763 citations, 64 full-text papers were screened and five papers that met the inclusion criteria were included in the final analysis. None of the included studies complied with all NOS criteria, and as only two studies were eligible for meta-analysis, this was not performed. CONCLUSIONS: Only limited conclusions can be drawn from this systematic review, due to the small number of studies included, their heterogeneity, and their high risk of bias. Future studies that take into consideration both upper and lower jaws, that use the same technique to measure skeletal and jaw BMD (ideally dual-energy X-ray absorptiometry, DXA), and that account for confounding variables (such as medications/diseases affecting bone metabolism and demographics) are needed to provide more robust conclusions.

A systematic review of implant outcomes in treated periodontitis patients.

OBJECTIVES: To investigate the effect of treated periodontitis on implant outcomes in partially edentulous individuals compared with periodontally healthy patients. MATERIAL AND METHODS: Longitudinal studies reporting on implant survival, success, incidence of peri-implantitis, bone loss and periodontal status, and on partially dentate patients with a history of treated periodontitis were included. RESULTS: The search yielded 14,917 citations. Twenty-seven publications met the inclusion criteria for qualitative data synthesis. Implant success and survival were higher in periodontally healthy patients, whilst bone loss and incidence of peri-implantitis was increased in patients with history of treated periodontitis. There was a higher tendency for implant loss and biological complications in patients previously presenting with severe forms of periodontitis. The strength of the evidence was limited by the heterogeneity of the included studies in terms of study design, population, therapy, unit of analysis, inconsistent definition of baselines and outcomes, as well as by the inadequate reporting of statistical analysis and accounting for confounding factors; thus, meta-analysis could not be performed. CONCLUSIONS: Implants placed in patients treated for periodontal disease are associated with higher incidence of biological complications and lower success and survival rates than those placed in periodontally healthy patients. Severe forms of periodontal disease are associated with higher rates of implant loss. However, it is critical to develop well-designed, long-term prospective studies to provide further substantive evidence on the association of these outcomes.

Experimental models for guided bone regeneration in healthy and medically compromised conditions.

The increased use of dental implants and related bone-augmentation procedures creates a need for reliable proof-of-principle preclinical models for evaluating different bone-regenerative techniques. The simulation of clinical scenarios by such models is of importance when the experiments are designed in order for the outcomes to provide basic points of clinical relevance. At the same time, the increased proportion of the population with different chronic diseases of ageing necessitates the need to reproduce these conditions in the same proof-of-principle preclinical models to allow evaluation of the effect of the relevant chronic disease on the bone-healing process. This review presents a number of 'proof-of-principle' preclinical models in health and in chronic systemic conditions in which the guided bone regeneration principle was evaluated.

Does ridge preservation following tooth extraction improve implant treatment outcomes: a systematic review: Group 4: Therapeutic concepts & methods.

OBJECTIVE: (1) Primary focused question (Q1): to evaluate the effect of alveolar ridge preservation (ARP) on implant outcomes (implant placement feasibility, need for further augmentation, survival/success rates, marginal bone loss) compared with unassisted socket healing (USH) and (2) secondary focused question (Q2): to estimate the size effects (SE) of these outcomes in three different interventions (GBR, socket filler, socket seal). MATERIAL AND METHODS: Electronic (MEDLINE, EMBASE, Cochrane Central Register LILACS; Web of Science) and hand search was conducted up to July 2014. Randomised controlled trials (RCT), controlled clinical trials (CCT) and prospective cohort studies with USH as controls were eligible in the analysis for Q1. RCTs, CCTs and prospective case series, with or without USH as control, were eligible for Q2. RESULTS: Ten (8 RCTs, 2 CCTs) and 30 studies (21 RCTs, 7 CCTs, 2 case series) were included in the analysis for Q1 and Q2, respectively. The risk for bias was unclear or high in most of them. Q1: Implant placement was feasible in ARP-treated and USH sites. These implants presented similar survival/success rates and marginal bone levels. The need for further augmentation decreased when ARP was performed (Relative risk: 0.15, 95% CI: 0.07-0.3). Q2: The SE for implant placement feasibility was 98.5% (95% CI: 96.4-99.6) in GBR and 96.2 (95% CI: 93.1-98.2) in socket filler group. The SE for need for further augmentation was 11.9 (95% CI: 5.6-19.9) for GBR and 13.7% (95% CI: 5.0-25.6) for socket filler groups. GBR and socket filler presented similar SE for survival/success rates and average marginal bone loss. Limited data were available for implant-related outcomes in sites treated with socket seal. CONCLUSIONS: There is limited evidence to support the clinical benefit of ARP over USH in improving implant-related outcomes despite a decrease in the need for further ridge augmentation during implant placement. Similar implant placement feasibility, survival/success rates and marginal bone loss should be anticipated following ARP or USH. Currently, it is not clear which type of ARP intervention has a superior impact on implant outcomes.

Therapeutic concepts and methods for improving dental implant outcomes. Summary and consensus statements. The 4th EAO Consensus Conference 2015.

BACKGROUND: Different therapeutic concepts and methods have been proposed for improving dental implant outcomes in three specific clinical situations: (i) the fresh extraction socket with alveolar ridge preservation protocols; (ii) the posterior maxilla with limited bone height with either the placement of regular-sized implants after sinus elevation and grafting or short dental implants and; (iii) the posterior mandible with limited bone height with either vertical bone augmentation and placement of implants or short dental implants. MATERIALS AND METHODS: Three systematic reviews, based on randomized and controlled clinical trials have evaluated the efficacy of these different therapeutic modalities in terms of dental implant outcomes. RESULTS AND CONCLUSIONS: Interventions aimed for alveolar ridge preservation have shown efficacy in terms of allowing the placement of dental implants and for reducing the need of further augmentation procedures at implant placement. Both therapeutic options, the placement of implants after sinus elevation and grafting or short dental implants, were valid alternatives in the treatment of the posterior maxilla with deficient bone availability, although short implants resulted in fewer complications. Similarly, the placement of implants in vertically augmented bone rendered comparable outcomes with those of short implants in the treatment of the posterior mandible, but short implants resulted in fewer complications.

A systematic review on the critical size defect model.

OBJECTIVES: To systematically review the literature data regarding the critical size defect (CSD) in adult rat calvaria and to determine which defect dimensions could be considered as being critical size. MATERIAL AND METHODS: A literature search was conducted at Ovid Medline and Embase up to July 2012. Studies presenting with at least one of the primary outcomes of interest (number of defects with complete closure and the percentage of new bone formation (%NBF) in rat calvaria) were included. Screening, data extraction and quality assessment were conducted independently and in duplicate. RESULTS: From 1461 citations, 257 full-text papers were screened and 61 papers were included in the analysis. Fourteen of 937 evaluated defects presented complete closure. Only 7 and 6 untreated sites in 5.0- and 6.0-mm-diameter defects, respectively, showed complete closure. A great variability among the preclinical models was seen, and the meta-analysis result showed a high heterogeneity regarding the mean %NBF. The mean %NBF according to the defect dimension was as follows: 18.29% and 21.44% for 5.0 mm central single defects at 1 and 3 months, respectively; 17.55%, 20.24% and 22.65% for 5.0 mm bilateral defects; 9.81%, 12.56% and 7.96% for 8.0 mm single defect; 11.18%, 9.48% and 26.24% for 9.0 mm single defects at 1, 2 and 3 months, respectively. CONCLUSION: Calvarial defects with a diameter of 5.0 mm could be considered as a CSD. However, there is a necessity for further standardization of the rat calvaria model to enable more accurate comparison among future studies.