Search

Objective: Exposure to aerosol spray generated by high-speed handpieces (HSHs) and ultrasonic scalers poses a significant health risk to oral health practitioners from airborne pathogens. Aerosol generation varies with different HSH designs, but to date, no study has measured this. Materials and methods: We measured and compared aerosol generation by (1) dental HSHs with 3 different coolant port designs and (2) ultrasonic scalers with no suction, low-volume evacuation (LVE) or high-volume evacuation (HVE). Measurements used a particle counter placed near the operator’s face in a single-chair, mechanically ventilated dental surgery. Volume concentrations of aerosol, totaled across a 0.3–25-µm size range, were compared for each test condition. Results: HSH drilling and scaling produced significantly high aerosol levels (P < .001) with total volume concentrations 4.73×108µm3/m3 and 4.18×107µm3/m3, respectively. For scaling, mean volume of aerosol was highest with no suction followed by LVE and HVE (P < .001). We detected a negative correlation with both LVE and HVE, indicating that scaling with suction improved operator safety. For drilling, simulated cavity preparation with a 1-port HSH generated the most aerosol (P < .01), followed by a 4-port HSH. Independent of the number of cooling ports, lack of suction caused higher aerosol volume (1.98×107 µm3/m3) whereas HVE significantly reduced volume to −4.47×105 µm3/m3. Conclusions: High concentrations of dental aerosol found during HSH cavity preparation or ultrasonic scaling present a risk of infection, confirming the advice to use respiratory PPE. HVE and LVE both effectively reduced aerosol generation during scaling, whereas the new aerosol-reducing ‘no air’ function was highly effective and can be recommended for HSH drilling.

Resorption of alveolar bone after tooth extraction is a common problem often requiring bone grafting. The success of the grafting procedures is dependent on multiple factors including the presence of growth factors. This is the first in vivo study to investigate the role of the pleiotrophin family of cytokines in alveolar bone regeneration. This research investigated the role of the pleiotrophin-midkine (PTN-MDK) axis during osteogenesis, with and without a grafting material, after tooth extraction in a sheep model.Thirty Romney-cross ewes were anesthetized, and all premolar teeth on the right side were extracted. The sockets were randomized to controls sites with no treatment and test sites with Bio-Oss® graft material and Bio-Gide® membrane. Samples were harvested after sacrificing animals 4, 8, and 16 weeks post-grafting (n = 10 per time-point). Tissue for qRTWithin the healing sockets, high expression of genes for PTN, MDK, NOTCH2, and ALK was found at all time-points and in both grafted and non-grafted sites, while PTPRZ1 was only expressed at low levels. The relative gene expression of the PTN family of cytokines was not statistically different at the three time-points between test and control groups (p .05). Immunohistochemistry found PTN and MDK in association with new bone, NOTCH2 in the connective tissue, and PTPRZ1 and ALK in association with cuboidal osteoblasts involved in bone formation.The PTN-MDK axis was highly expressed in both non-grafted and grafted sockets during osteogenesis in a sheep model of alveolar bone regeneration with no evidence that grafting significantly affected expression. The activation of NOTCH2 and PTPRZ1 receptors may be important during bone regeneration in vivo. The discovery of the PTN-MDK axis as important during alveolar bone regeneration is novel and opens up new avenues of research into these stably expressed highly active cytokines. Growth factor supplementation with PTN and/or MDK during healing may be an approach for enhanced regeneration or to initiate healing where delayed.

Zirconia ceramic (ZC) implants are becoming more common, but comparisons between preclinical histology and long-term clinical trials are rare. This investigation comprised (1) 8-year clinical follow-up of one-piece ZC or titanium (Ti) implants supporting full overdentures and (2) histomorphometric analysis of the same implants in an animal model, comparing implants with various surface treatments. Methods: (1) Clinical trial: 24 completely edentulous participants (2 groups of N = 12) received 7 implants (one-piece ball-abutment ZC or Ti; maxilla N = 4, mandible N = 3) restored with implant overdentures. Outcomes after 8-years included survival, peri-implant bone levels, soft-tissue responses, and prosthodontic issues. (2) Preclinical trial: 10 New Zealand sheep received 4 implants bilaterally in the femoral condyle: Southern Implants ZC or Ti one-piece implants, identical to the clinical trial, and controls: Southern ITC® two-piece implants with the same surface or Nobel (NBC) anodised (TiUnite™) surface. %Bone-implant contact (%BIC) was measured after 12 weeks of unloaded healing. Results: 8 of 24 participants (33%) of an average age of 75 ± 8 years were recalled; 21% of original participants had died, and 46% could not be contacted. 80.4% of implants survived; excluding palatal sites, 87.5% of Ti and 79% of ZC implants survived. All failed implants were in the maxilla. Three ZC implants had fractured. Bone loss was similar for Ti vs. ZC; pocket depths (p = 0.04) and attachment levels (p = 0.02) were greater for Ti than ZC implants. (1.7 ± 1.6 mm vs. 1.6 ± 1.3 mm). All implants in sheep femurs survived. %BIC was not statistically different for one-piece blasted surface Ti (80 ± 19%) versus ZC (76 ± 20%) or ITC® (75 ± 16 mm); NBC had significantly higher %BIC than ITC (84 ± 17%, p = 0.4). Conclusion: Short-term preclinical results for ZC and Ti one-piece implants showed excellent bone-implant contact in unloaded femoral sites. This differed from the long-term clinical results in older-aged, edentulous participants. While ZC and Ti implants showed equivalent performance, the risks of peri-implantitis and implant loss in older, completely edentulous patients remain a significant factor.

Background The Hall Technique (HT) is a method of restoring decayed primary teeth using stainless steel crowns (SSCs) without tooth preparation, caries removal, or local anaesthetic. Aim To investigate the ultrastructural, biomechanical, and chemical characteristics of teeth managed with the Hall Technique in comparison with conventional SSC (controls). Design Twelve HT-treated primary molars and four controls were analysed. Teeth were dehydrated in ethanol, embedded in methylmethacrylate, mesio-distally sectioned, X-rayed, mounted, and polished. Biomechanical, ultrastructural, and chemical characterisation was performed for carious lesion and sound areas of each specimen. Results Pre-treatment and post-treatment X-rays showed evidence of little to no caries progression over time. In carious lesions, mean hardness and elastic modulus values were lower in HT-treated teeth than in controls. In both controls and HT-treated teeth, carious lesions had the lowest %wt of Ca and P of all tissues sampled. Conclusions Although the retained carious tissue was biomechanically more compromised in HT-treated teeth, the Ca and P values were higher than reported elsewhere for carious lesions in primary molars, suggesting remineralisation may have occurred in caries in HT-treated teeth. Future investigations will help elucidate the processes involved with carious lesion arrest under SSC.

PURPOSE This study aimed to determine expressions of hepatocyte growth factor (HGF) and MET proto-oncogene receptor tyrosine kinase (MET) in palatal periosteum (PP) and to examine the effect of HGF/MET on osteogenic differentiation of human palatal periosteum-derived mesenchymal stem cells (PD-MSCs). METHODS HGF/MET proteins in human palatal periosteum (n = 3) were localized using immunohistochemistry. PD-MSCs (n = 3) were cultured in serum-free Essential 8 (E8) medium or osteogenic medium with and without Capmatinib, a selective ATP-inhibitor of MET. HGF concentration in vitro was measured with ELISA. Relative gene expression was quantified from PD-MSCs by quantitative reverse transcription real-time polymerase chain reaction. RESULTS Immunohistochemistry detected co-localization of HGF and MET protein in PP. HGF protein levels were significantly higher (P < 0.05) in osteogenic media (day 21: 12.19 ± 8.36 ng/mL) than in E8 medium (day 21: 0.42 ± 0.72 ng/mL). MET inhibitor had a limited feedback effect on the expression profile of the osteogenic genes tested. Gene expression levels for all but three genes were comparable in serum-free and osteogenic media at all time points. CONCLUSION HGF/MET present in human PP and HGF is upregulated in vitro during osteogenesis; however the targeted pathways controlled by MET may not involve osteoblast maturation.

The South Island of New Zealand saw several major waves of migration in the mid-nineteenth century, predominantly from Europe but also with an ethnically distinct Chinese presence. The rural community of Milton, Otago, was a settler community established primarily by immigrants from the United Kingdom in search of a better quality of life. However, these settlers faced unique challenges related to surviving in an isolated location with very little infrastructure compared to their origin populations. In 2016, excavation was undertaken at St. John’s burial ground, Milton, with the object of using bioarchaeological methods to elucidate the lived experience of the first organized European settlement of this region, particularly in terms of health and disease. Here we present a case study of Burial 21 (B21), a male individual of known identity and a documented cause of death. We use biochemical and paleopathological methods to ground-truth his written history, which includes a period of invalidism due to tuberculosis, and discuss the implications of our findings for the community, provision of care, and quality of life in rural colonial New Zealand. He maha tonu ngā hekenga tāngata ki Te Waka a Māui i ngā tau kei waenga pū o te rau tau 1800, ko te nuinga nō Ūropi, heoi he tokomaha tonu nō Haina. Nā ngā manene nō Peretānia te hapori o Milton i whakatū ki Tokomairaro, i Ōtākou, i tō rātou hiahia ki tētehi oranga kounga ake i tō rātou oranga i Peretānia. Heoi, ko ētehi o ngā wero nui i tau ki ngā manene nei i ahu mai i te noho pūreirei ki tētehi wāhi kāore rawa ngā ratonga i rite ki ngā wāhi i ahu mai ai rātou. I te tau 2016, i hahu kōiwi i te urupā o Hato Hone, i Milton, hei whakamātau i te kaha o te ora me ngā momo mate i pā atu ki ngā tāngata whai i noho i te rohe nei. Nei rā he ripoata mō tētehi kua hahua, kua tapaina ko B21, he tāne ia, ko tōna ingoa kua mōhiotia, ko tōna mate kua āta tuhia. Kua āta whakamātauria ōna kōiwi me ōna toenga kiko mō ngā tohu ora me ngā tohu mate, kia mārama ai mena rānei e hāngai ana ngā tuhinga rongoā mōna, ngā mea i tuhia nōna e takatū ana, tae atu ki te wā i tūroro ia i te mate kohi, ki ngā tohu e puta ana i te mātauranga Rongoā-Koiora ō nāianei. Ka matapakina ngā hīrautanga o ngā kitenga me te māramatanga kua puta i tēnei rangahau e pā ana ki te hapori, ki ngā ratonga hauora, me te kounga o te oranga mō te hunga noho tuawhenua i tērā wā i Aotearoa.

All-ceramic dental restorations are now regularly being used in clinical situations. Forces applied to ceramic dental restorations can result in failure due to cracking. Dental restorations may be ...

Mesenchymal stem cells in dentistry have multiple potential applications including alveolar ridge preservation and repair, cleft palate reconstruction, sinus grafting and ultimately pulp and dentin...

Manuka oil, an essential oil derived from the Leptospermum scoparium, has been traditionally used for wound care and as a topical antibacterial, antifungal, and anti-inflammatory. However, the essential oil is not well retained at mucosal sites, such as the oral cavity, where the benefits of the aforementioned properties could be utilized toward the treatment of persistent biofilms. Within this study, L. scoparium essential oil was incorporated into a semisolid emulsion for improved delivery. The safety profile of L. scoparium essential oil on human gingival fibroblasts was determined via cell viability, cytotoxicity, and caspase activation. The minimal bactericidal concentration of L. scoparium essential oil was determined, and the emulsionʼs antibiofilm effects visualized using confocal laser scanning microscopy. L. scoparium essential oil demonstrated a lower IC50 (0.02% at 48 h) when compared to the clinical control chlorhexidine (0.002% at 48 h) and displayed lower cumulative cytotoxicity. Higher concentrations of L. scoparium essential oil (≥ 0.1%) at 6 h resulted in higher caspase 3/7 activation, suggesting an apoptotic pathway of cell death. A minimal bactericidal concentration of 0.1% w/w was observed for 6 oral bacteria and 0.01% w/v for Porphyromonas gingivalis. Textural and rheometric analysis indicated increased stability of emulsion with a 1 : 3 ratio of L. scoparium essential oil: Oryza sativa carrier oil. The optimized 5% w/w L. scoparium essential oil emulsion showed increased bactericidal penetrative effects on Streptococci gordonii biofilms compared to oil alone and to chlorhexidine controls. This study has demonstrated the safety, formulation, and antimicrobial activity of L. scoparium essential oil emulsion for potential antibacterial applications at mucosal sites.

Introduction: Titanium (Ti) is widely accepted as a biomaterial for orthopaedic and dental implants, primarily due to its capacity to integrate directly into the bone and its superior corrosion resistance. It has been suggested that titanium–zirconium alloy (TiZr), with 13–17% of zirconium, has better mechanical properties than pure Ti, but there are very few published studies assessing the suitability of TiZr for high-load- bearing implants. This study aimed to compare the mechanical properties and microstructures of TiZr and commercially pure titanium (Ti). Methodology: Pure Ti and TiZr alloy discs were prepared and subjected to characterisation by nanoindentation, electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). Results: The TiZr alloy was found to have significantly lower elastic modulus value (p < 0.0001) and greater hardness than Ti (p < 0.05). The EDS results confirmed the presence of Zr (13–17%) in the TiZr alloy, with XRD and EBSD images showing microstructure with the alpha phase similar to commercially available Ti. Conclusion: The lower elastic modulus, higher hardness, presence of alpha phase, and the finer grain size of the TiZr alloy make it more suitable for high-load-bearing implants compared to commercially available Ti and is likely to encourage a positive biological response.

Harvesting, expanding, and re-implanting osteogenic mesenchymal stem cells (MSCs) avoids the donor-site morbidity associated with autogenous grafting from bone marrow. Mesenchymal stem cells sourced from the palatal periosteum could be an alternative to isolation of such cells using bone marrow aspiration procedures. For safe use in human therapy, MSCs should be expanded in culture medium that is free from animal or human-derived serum. In this study we localized, quantified, and characterized MSCs from palatal periosteum cultured in serum-free, xeno-free Essential 8 medium. A portion of the palatal periosteum tissues from three patients were dual-immunostained with MSC-specific markers (CD105, CD90, and CD73). The remaining portions were expanded in culture, and the isolated MSCs were analyzed using flow cytometry and tri-lineage differentiation. Palatal periosteum sections were found to contain CD105-, CD90-, and CD73-positive cells. The cultured cells were 73.0 ± 6.7% (mean ± SD) positive for all three MSC-specific markers and were without hematopoietic stem cell (HSC) markers 0.5 ± 0.3% (mean ± SD). Tri-lineage differentiation analysis confirmed that palatal periosteum cells could become adipoblasts, chondroblasts, and osteoblasts. The results demonstrate that palatal-derived MSCs could be detected in situ within small niches, and when expanded in serum-free, xeno-free medium represent a viable source of MSCs for clinical use.

Silver nanoparticles (AgNPs) are widely studied for their broad-spectrum antimicrobial effects, and can be utilised readily in biomaterials, however the cellular safety of specific AgNP formulations should be profiled prior to clinical usage. This study determined the cytotoxic effect of small sized (6 nm) alpha lipoic acid capped-AgNPs on human gingival fibroblasts (HGF), as compared to ionic silver and clinical antiseptics. The metabolic pathway was investigated to determine the cellular effects on HGF cells. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) was established for a range of oral related bacteria. Results showed that cell viability decreased with increasing AgNP concentration, whereas lower concentrations of AgNPs, (≤5 μg ml−1) caused a significant increase in cell proliferation at 24 and 72 hour time points. The cytotoxicity profile of AgNPs exhibited significantly lower concentrations, relative to the dose of clinical efficacy, when compared to clinical antiseptics. Caspase 3/7 was not significantly altered when HGF cells were treated with 0.225 μg ml−1 AgNPs, indicating cell necrosis rather than apoptosis. Quantitative RT2-PCR detected an upregulation of genes associated with oxidative stress and the G2M cell cycle checkpoint at ≤4 hours, but expression levels returned to levels consistent with control cells at 24–96 hours. An MIC range of 2.5–12.5 μg ml−1 (min. Escherichia coli, Streptococcus mutans, S. mitis; max. Staphylococcus aureus) was determined across the bacterial species tested and an MBC range of 5–100 μg ml−1 (min. E. coli, max. S. mutans). The antimicrobial profile was similar to that of AgNO3 which suggested that the antimicrobial effect may be influenced by free Ag+ release. It was concluded that alpha lipoic acid capped AgNPs possess limited cytotoxic activity to HGF cells when compared to clinically utilised oral antiseptics, observed via the cellular recovery after initial AgNP treatment and a lack of cumulative cytotoxic effect, whilst maintaining a broad range antimicrobial effect of the AgNPs.

Bite forces are studied in order to understand a wide range of factors pertaining to the mastication system. Various strain gauge transducers have been employed to measure bite forces, with several descriptions of these available in the literature; unfortunately, many reports provide insufficient detail to enable accurate reproduction. The aim of this project was to develop a bite force transducer with the capability of measuring maximum voluntary bite forces between individual opposing tooth surfaces. Furthermore, in an attempt to address the issue of vague device descriptions in the available literature, a detailed account of the transducer development has been included. A novel strain gauge transducer was designed and built. Bite forces of forty individuals were measured to verify the capabilities and clinical application of the device.

Background Clinical trials have suggested that dental implants with a tapered configuration have improved stability at placement, allowing immediate placement and/or loading. The aim of this systematic review and meta-analysis was to evaluate the implant stability of tapered dental implants compared to standard parallel-walled dental implants. Materials and methods Applying the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, randomized controlled trials (RCTs) were searched for in electronic databases and complemented by hand searching. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool and data were analyzed using statistical software. Results A total of 1199 studies were identified, of which, five trials were included with 336 dental implants in 303 participants. Overall meta-analysis showed that tapered dental implants had higher implant stability values than parallel-walled dental implants at insertion and 8 weeks but the difference was not statistically significant. Tapered dental implants had significantly less marginal bone loss compared to parallel-walled dental implants. No significant differences in implant failure rate were found between tapered and parallel-walled dental implants. Conclusions There is limited evidence to demonstrate the effectiveness of tapered dental implants in achieving greater implant stability compared to parallel-walled dental implants. Superior short-term results in maintaining peri-implant marginal bone with tapered dental implants are possible. Further properly designed RCTs are required to endorse the supposed advantages of tapered dental implants in immediate loading protocol and other complex clinical scenarios.

Disease and trauma leading to tooth loss and destruction of supporting bone is a significant oral handicap, which may be addressed through surgical therapies that aim to regenerate the lost tissue. Whilst complete regeneration of teeth is still aspirational, regeneration of supporting structures (dental pulp, cementum, periodontal ligament, bone) is becoming commonplace, both for teeth and for titanium dental implants that are used to replace teeth. Most grafting materials are essentially passive, however the next generation of oral regenerative devices will combine non-antibiotic antimicrobials and/or osteogenic or inductive factors and/or appropriate multipotential stem cells. The review gives an overview of the approaches taken, including fabrication of novel scaffolds, incorporation of growth factors and cell-based therapies, and discusses the preclinical animal models we employ in the development pathway.

The use of definitive abutments (DAs) at time of implant placement has been introduced to overcome limitations of dis/reconnection of healing/provisional abutments (PAs). With little and inconsistent information in the literature regarding the effectiveness of using DAs, the aim of this systematic review is to examine marginal bone and soft tissue level changes, technical and biologic complications, and implant failure rate associated with use of DAs and PAs.This systematic review was prepared according to guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and online trial registers were searched for studies comparing use of DAs and PAs. The Cochrane Collaboration risk of bias tool was used to assess selected studies, and meta-analyses were performed using statistical software.A total of 1,124 citations were identified. Of these, seven trials with 363 dental implants in 262 participants were included in the analysis. Pooled estimates for marginal bone level changes showed significant differences between the two prosthetic techniques in favor of using DAs. No significant differences were found in soft tissue level changes, technical and biologic complications, or implant failure rate.Within the limitations of this review, DAs appear to be a viable alternative to PAs at time of implant placement. However, favorable changes in peri-implant marginal bone level associated with use of DAs should be viewed with caution as its clinical significance is still uncertain.

Background and objective The aim of this pilot study was to characterize surface morphology and to evaluate resorption and osseous healing of two deproteinated bovine bone graft materials after sinus grafting in a large animal model. Material and methods Surfaces of a novel particulate bovine bone graft, Moa-Bone® were compared with Bio-Oss® using scanning electron microscopy. Six sheep then had maxillary sinus grafting bilaterally, covered with BioGide® . Grafted maxillae were harvested after 4, 6 and 12 weeks. Healing was described for half of each site using resin-embedded ground sections. For the other half, paraffin-embedded sections were examined using tartrate resistant acid phosphatase staining for osteoclast activity, runt-related transcription factor2 immunohistochemistry for pre-osteoblasts and osteoblasts and proliferating cell nuclear antigen for proliferative cells. Results Moa-Bone® had a smoother, more porous fibrous structure with minimal globular particles compared with Bio-Oss® . After 4 weeks, woven bone formed on both grafts and the Moa-Bone® particles also showed signs of resorption. After 12 weeks, Moa-Bone® continued to be resorbed, however Bio-Oss® did not; both grafts were surrounded by maturing lamellar bone. Moa-Bone® was associated with earlier evidence of runt-related transcription factor 2-positive cells. Moa-Bone® but not Bio-Oss® was associated with strong tartrate resistant acid phosphatase-positive osteoclasts on the graft surface within resorption lacunae at both 4 and 6 weeks post-grafting. Conclusion Both materials supported osseous healing and maturation without inflammation. Moa-Bone® showed marked osteoclast activity after 4 and 6 weeks and demonstrated positive attributes for grafting, if complete remodeling of the graft within the site is desired. Further optimization of Moa-Bone® for maxillofacial applications is warranted.

Purpose: To investigate the presence of metallic particles in the peri-implant mucosa around titanium dental implants after 5 years of loading using single-implant crowns with respect to clinical signs of peri-implant inflammation. Materials and Methods: Sixteen participants from an ongoing, prospective, single-arm clinical trial who had received titanium dental implants restored with single maxillary crowns veneered to zirconia abutments were available for the study. Exfoliative cytology samples were obtained from the periimplant tissues and contralateral tooth sites using microbrushes and were evaluated by means of light microscopy (LM), scanning electron microscopy, and energy-dispersive spectroscopy (EDS). Trace elemental analysis was also carried out on the microbrushes using inductively coupled plasma mass spectrometry. Peri-implant and periodontal parameters (plaque, bleeding, attachment level, radiographic bone levels) were recorded. Results: Titanium particles were found in both the single-implant crown and contralateral natural tooth sites. LM and EDS analyses showed significantly higher numbers of Ti particles at the implant-abutment interfaces (mean = 14.168; SD = 2.36) and in the internal aspects of peri-implant mucosa in contact with the prostheses (mean = 4.438; SD = 2.22) when compared with other test and control areas. Mean probing depths were ≤ 3 mm, and no differences were found in plaque or bleeding on probing between implant and tooth sites. Median bone levels were within the normal range for both implant (mesial: 0.5 mm; distal: 0.8 mm) and tooth (mesial: 1.5 mm; distal: 1.8 mm) sites. Conclusion: Loading of single-implant zirconia crowns can cause the release of Ti particles because of functional wear at the implant-abutment level. The presence of these metal particles in the peri-implant area did not appear to affect peri-implant health in this patient group.

Autogenous bone grafting requires a donor site and may lose substantial volume during remodeling. Several bone replacement materials (BRMs) are under development to overcome these limitations, especially for indications for minimally intervention surgeries. The objective of our study was to assess the potential of an equine collagen cone reinforced with biphasic calcium phosphate (CC-BCP) particles and deproteinized bovine bone matrix (BBM) coated with polylactic acid, and poly-e-caprolactone copolymer (BBM-PCC) and then to compare the outcomes with a deproteinized BBM and an equine CC without a filler in a sheep sinus grafting model in the Elleven female sheep were selected. Two experimental sites on each side of the animals were prepared using an extraoral approach for maxillary sinus wall. The four treatments were performed in each animal through a standardized 10-mm access window. While the BBM access was covered with a collagen membrane, all other sites were closed with an equine collagen membrane. All animals were euthanized after 16 weeks. New bone (NB), residual graft particles, and connective tissue were measured in undemineralized resin-embedded sections. As a result, one sheep did not survive the surgery. All sites in the remaining 10 sheep healed uneventfully. All CC and BBM-PCC grafts resorbed and failed to augment the sinuses. BBM and CC-BCP, in contrast, showed some histologic evidence of NB and surgical site augmentation. The NB fraction in the latter two groups accounted for 10 ± 9 and 4 ± 5%, respectively (p > 0.05). In conclusion, BBM-PCC and collagen cone performed poorly for sinus floor augmentation, while deproteinised BBM and reinforced collagen cone demonstrated comparable outcomes.

Finite element (FE) models of the infant human head may be used to discriminate injury patterns resulting from accidents (e.g. falls) and from abusive head trauma (AHT). Existing FE models of infant head impacts are reviewed. Reliability of the material models is the major limitation currently. Infant head tissue properties differ from adults (notably in suture stiffness and strain-to-failure), change with age, and experimental data is scarce. The available data on scalp, cranial bone, dura, and brain are reviewed. Data is most scarce for living brain. All infant head model to date, except one, have used linear elastic models for all tissues except the brain (viscoelastic or Ogden hyperelastic), and do not capture the full complexity of tissue response, but the predicted whole-head response may be of acceptable accuracy. Recent work by Li, Sandler and Kleiven has used hyperelastic models for scalp and dura, and an orthotropic model for bone. There is a need to simulate falls from greater than one metre, and blunt force impacts.

PURPOSE To investigate whether human adipose-derived stem cells will form a functional bone-like matrix on titanium substrates. The behavior of human adipose-derived stem cells was examined when grown in either serum-free, xeno-free stem cell growth medium or osteogenic differentiation medium and cultured on either machined titanium (MTi) or on roughened alumina-blasted titanium (ABTi) discs. MATERIALS AND METHODS Cellular proliferation, extracellular mineralized matrix production, osteogenic-related protein production (RUNX2 and osteocalcin), and gene expression for pluripotency and self-renewal (TERT and OCT4) and osteogenic-related (MSX2, RUNX2, and BGLAP) genes were performed. RESULTS Human adipose-derived stem cells in serum-free medium (hADSC) proliferated at a higher rate compared with osteogenically differentiated cells (hOS-ADSC); however, the osteogenically committed cells produced more mineralized matrix on the titanium surfaces compared with either tissue culture plastic or the undifferentiated cells. The immunofluorescence analysis showed that human adipose-derived stem cells cultured in serum-free medium and osteogenic differentiation medium produced RUNX2 on both the machined titanium surface and on the alumina-blasted titanium surface after 7 days in culture. Only osteogenically differentiated cells produced osteocalcin after 21 days. Relative gene expression showed stable expression of MSX2, RUNX2, and BGLAP over time on all surfaces. Only osteogenically differentiated cells displayed osteogenic characteristics over time. CONCLUSION This study confirmed that human adipose-derived stem cells could be successfully grown in serum-free, xeno-free culture medium suitable for clinical use. Adipose-derived stem cells thus show potential utility for bone regeneration in association with titanium surfaces.

Aim The aim of this study was to investigate the capacity of adipose-derived stem cells (ADSC), grown in serum-free conditions, to regenerate bone around titanium discs with different titanium surfaces. Material and methods Ovine ADSC (oADSC) were isolated from seven sheep and cultured using serum-free and osteogenic conditions. Prior to in vivo testing, the growth and osteogenic behaviour of these cells were analysed in vitro using cell proliferation and extracellular matrix mineralisation assays. The bone regenerative capacity of autologous oADSC was evaluated in vivo on titanium discs in a sheep femur epicondyle model. Machined (MTi) and alumina-blasted (ABTi) titanium discs were used. Bone regeneration within the defects was evaluated after 1 month using histology and histomorphometry. PKH26 cell-tracking dye was used to verify the persistence of oADSC in the surgical wound. Results oADSC sourced from five of seven sheep differentiated into osteoblast-like cells. Cellular proliferation was reduced only for osteogenically induced oADSC (oOS-ADSC) grown on ABTi, compared to non-induced oADSC grown on ABTi and tissue culture polystyrene (P = 0.03 and 0.02 respectively). There was no significant difference for in vitro mineralisation assays comparing oADSC with oOS-ADSC, regardless of implant surface type. oADSC labelled with PKH26 were detected 1 month after surgery within the defect. There was no difference in bone regeneration between the bone defects treated with oADSC vs. just blood clot. Conclusion After 1-month healing, the use of autologous oADSC did not improve bone regeneration in defects containing titanium devices with different surfaces.

Objectives Spark discharge anodic oxidation forms a porous oxide film on titanium implant surfaces, which may increase surface roughness and enhance early osseointegration. This study aimed to clinically and histomorphometric compare commercially-available sandblasted (RBM) implants, treated with hydrothermal anodization and placed into an animal maxillary sinus model. Materials and methods Thirty 3.75 mm × 8.5 mm threaded titanium implants were placed into the maxillary sinuses of 10 sheep via an external approach, with three test groups and 10 implants per group: right side, Control = CP-titanium with RBM surface, Test group 1 = CP-titanium with RBM + anodized surface; left side, Test group 2 = Ti-6Al-7Nb with RBM + anodized surface. Schneiderian membranes were elevated but not bone grafted. Resonant frequency analysis (RFA) was measured at surgery. Animals were sacrificed after 1 month unloaded healing. Resin-embedded undemineralized ground-sections were digitised, and mean bone-implant contact (% BIC) was measured bilaterally for the best-three consecutive threads. Results Seven of 30 implants showed signs of failure. RFA was low at placement but did not differ between the groups (group mean ISQ values ranged from 23 to 35; χ(2) = 0.37). RFA was not repeated at sacrifice due to implant instability. Histomorphometric analysis showed % BIC was highest for control (34.8 ± 15.7), followed by Test 1 (29.6 ± 18.1) and Test 2 implants (23.3 ± 22.7), but this difference was not statistically significant (χ(2) = 0.3). Discussion and conclusions Early integration of RBM implants placed into thin maxillary sinus walls was not enhanced by hydrothermal anodization of implant surfaces. This may be related to the initial low stability of the implants and the relatively short healing period. However, non-anodized RBM surfaces showed promising results, with % BIC values comparable to the best estimates of other studies using sinus grafting. Whether the modification of the implant surfaces through anodization with simultaneous sinus grafting would promote enhanced early osseointegration, is a subject of future research.

Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9%) (p=0.002). Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3%) (p=0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.

Purpose: Lateral maxillary sinus floor elevation (LMSFE) is a predictable preprosthetic surgical procedure that is used to overcome the limitations of the atrophied alveolar ridge for the placement of oral implants. Techniques using piezoelectric devices (PEDs) and conventional rotary instruments have been described for LMSFE in the literature, with little information regarding their efficiency in terms of membrane perforation, operating time, and implant outcomes. The aim of this systematic review was to examine the intra- and postoperative events associated with the use of PEDs and conventional rotary instruments for LMSFE. Materials and Methods: This systematic review was prepared according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The literature was searched for studies comparing the use of PEDs with conventional rotary instruments for LMSFE. The Cochrane Collaboration risk of bias tool was used to assess the studies selected, and meta-analyses were performed using statistical software. Results: A total of 124 citations were identified. Of these, four studies with 178 LMSFEs in 120 participants were included. The pooled estimates for the risk of sinus membrane perforation did not show any significant difference between the two surgical techniques (risk ratio, 0.87; 95% confidence interval, 0.40–1.91; P = .73). Similarly, no significant difference in implant failure was found after 1 year of functional loading. The overall meta-analysis showed a statistically significant difference in the operating time between the two techniques with more time required for PED. Conclusion: The intra- and postoperative events associated with the use of PEDs and conventional rotary instruments for LMSFE are comparable.

OBJECTIVES: Electrospun cotton wool-like nanocomposite (ECWN) is a novel synthetic bone substitute that incorporates amorphous calcium phosphate nanoparticles into a biodegradable synthetic copolymer poly(lactide-co-glycolide). The objectives of this study were to develop a tooth extraction socket model in sheep for bone graft research and to compare ECWN and bovine-derived xenograft (BX) in this model. MATERIAL AND METHODS: Sixteen cross-bred female sheep were used. Bilateral mandibular premolars were extracted atraumatically. Second and third premolar sockets were filled (Latin-square allocation) with BX, ECWN or left unfilled. Resorbable collagen membranes were placed over BX and selected ECWN grafted sockets. Eight sheep per time period were sacrificed after 8 and 16 weeks. Resin-embedded undemineralised sections were analysed for descriptive histology and histomorphometric analyses. RESULTS: At 8 weeks, there were with no distinct differences in healing among the different sites. At 16 weeks, osseous healing followed a fine trabecular pattern in ECWN sites. Non-grafted sites showed thick trabeculae separated by large areas of fibrovascular connective tissue. In BX grafted sites, xenograft particles were surrounded by newly formed bone or fibrovascular connective tissue. There were no statistically significant differences in bone formation across the four groups. However, ECWN sites had significantly less residual graft material than BX sites at 16 weeks (P = 0.048). CONCLUSIONS: This first description of a tooth extraction socket model in sheep supports the utility of this model for bone graft research. The results of this study suggested that the novel material ECWN did not impede bone ingrowth into sockets and showed evidence of material resorption.

Aim To evaluate in vitro topographical and composition changes by piezoelectric ultrasonic instrumentation with metallic and plastic tips on machined and moderately roughened titanium surfaces. Methods Twenty machined and moderately roughened laser-marked titanium discs were ultrasonically instrumented with metallic and plastic tips. Surface instrumentation was carried out with controlled pressure for 20 and 30 seconds at two power settings. For each time and power setting, instrumentation was repeated four times with one instrumentation per disc quadrant. Surface topography analysis was performed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Surface roughness measurements were compared between instrumented and non-instrumented surfaces. Surface element composition and rinsing solutions were evaluated using energy-dispersive spectroscopy (EDS) and trace elemental analysis using inductively coupled plasma mass spectrometry (ICPMS), respectively. Results SEM photomicrographs and CLSM 3D surface plot images of instrumented machined and moderately roughened surfaces demonstrated severe surface topographical alterations with metallic tips and mild to moderate changes for plastic tip instrumented sites. ICPMS analysis of the rinsing solutions identified titanium and other metal traces with the use of metallic tips, and mainly titanium and carbon when plastic tips were used. Surface EDS analysis showed elemental traces of the ultrasonic tips. Conclusion Ultrasonic instrumentation with metallic or plastic tips created surface topographical and compositional changes. Different changes in surface topography were noted between the surfaces, as the roughness of the machined surfaces increased while the extent of roughness of the moderately roughened surfaces decreased. The clinical relevance of these changes is yet to be determined.

Background Single implant crowns have become the preferred rehabilitation treatment option for replacing a missing tooth. Purpose This study evaluates 5-year clinical success of using tilted implants placed immediately after extraction followed by rehabilitation with all-ceramic crowns. Materials and methods Twenty-seven participants requiring 28 single implant crowns in the aesthetic zone of maxilla were recruited to participate in a single-arm clinical trial. All participants were rehabilitated according to immediate implant placement using CP grade 4 titanium implants with roughened surfaces and a 12°-angled platform. Provisional implant crowns were connected within 4 hours of implant placement and loaded according to progressive loading protocol. At 8 weeks (baseline), definitive screw-retained crowns fabricated using densely sintered zirconia abutments with the veneering porcelain were delivered. Participants were followed up to 5 years and 16 participants with 17 single implant crowns attended Year 5 recall. Data collection included changes in marginal bone levels (MBLs), mid-buccal mucosal levels (MBMLs), implant stability quotient (ISQ) values, and any prosthodontic maintenance issues. Results The mean changes in MBLs at each recall was bone fill of 0.5 ± 1.18 mm (surgery-baseline), increase of 0.1 ± 0.57 mm (baseline-Year 1), and marginal bone loss of 0.1 ± 0.25 mm (Years 1-5). A minimal change occurred with the MBMLs during the observation period. The mean ISQ value at each time point increased from 65.1 (implant placement), to 67.4 (baseline) and 69.9 (Years 1 and 5). Prosthodontic maintenance issues occurred only during the first year which included fracture of veneering ceramic and zirconia abutment as well as aesthetic concerns. Conclusions Within the limitations of this study, the data collected would suggest that replacing a single missing tooth using titanium oral implants with 12° platform tilt and zirconia abutments can be a successful rehabilitation option in the esthetically demanding zone of anterior maxilla.

Background Quantitative research methods provide clinicians with information about the effectiveness of interventions and determined causal-effect relationships, whereas qualitative research investigates other aspects of clinical implant practice, particularly the participants’ perspectives and expectations. The aim of the qualitative study was to understand the experience of participants with immediate single molar implants. Methods In-depth, audiorecorded, semistructured interviews were conducted with 15 participants who had participated in a controlled clinical trial of immediate molar implants. Participants were aged 36–77 years. Nine participants received single implants in mandibular molar fresh extraction sockets while the remaining participants had their implants in healed sites. The interviews that assessed participants’ perspectives of the pre-operative, operative, and postoperative phases of therapy were transcribed verbatim and analysed using inductive and content analysis. Results Participants took part in the clinical trial mainly because it offered oral implant therapy at a reduced cost. The affordability of implant treatment was the main factor in determining restorative options. Minimal differences were found between male and female participants of different age groups in terms of their perceptions of function and aesthetics. However, single molar implants did not have an impact on aesthetics and self-esteem. Participants’ expectations regarding the longevity of oral implants were not realistic and their knowledge about future maintenance needs was not adequate. Conclusions Using face-to-face verbal conversation more frequently may improve communication between clinicians and participants and minimize misunderstanding about the procedures of different treatment modalities. Special emphasis should be placed on understanding the importance of maintenance by spending more time with the participants to identify any future barriers to maintaining good outcomes of oral implants.

Background The use of a piezoelectric device (PED) for implant site preparation (ISP) has been introduced to overcome the limitations of using conventional drills (CDs). With little and inconsistent information in the literature regarding their efficiency for preparing implant osteotomies, the objective of this systematic review was to compare the use of CDs to PEDs for ISP with regard to implant stability values, marginal bone level changes, operating time, and dental implant failure rate. Methods The systematic review was prepared according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The literature was searched for studies that assessed the use of CDs and PEDs for ISP. The Cochrane Collaboration risk of bias tool was used to evaluate the selected studies and meta-analyses were performed using statistical software. Results A total of 755 citations were identified. Of these, 4 studies with 178 implant osteotomies in 80 participants were included. The pooled estimates for the implant stability showed significant differences between the 2 surgical techniques in favor of PEDs at baseline, 8 and 12 weeks. A statistically significant difference in the operating time was also shown between the 2 techniques with more time required using PED. The differences in marginal bone level changes or implant failure rate were not statistically significant. Conclusions With the limitations of this review in mind, PEDs appear to be a viable alternative to traditional drilling techniques for ISP. With the exception of prolonged operating time associated with the use of PEDs, both techniques were comparable in terms of the marginal bone level changes and the risk of implant failure. The favorable influence of the implant stability pattern related to the use of PEDs on the predictability of immediate and early loading protocols need to be confirmed in future studies.

Background Further validation of the risk indicators / predictors for peri-implant diseases is required to allow clinicians and patients to make informed decisions and optimize dental implant treatment outcomes. The aim of this study was to build prediction models, using Chi-square automatic interaction detection (CHAID) analysis, to determine which systemic-, patient-, implant-, site-, surgical- and prostheses-related risk indicators had more impact on the onset of peri-implant diseases. Methods A retrospective analysis of 200 patients who received implant-supported prostheses between 1998 and 2011 was conducted to evaluate the prevalences and risk indicators for peri-implant mucositis and peri-implantitis. The data were further analyzed using CHAID to produce two predictive models. Results The prevalence of peri-implant mucositis was 20.2% and 10.2% for patients and implants, respectively, while the prevalence of peri-implantitis was 10.1% at the patient level and 5.4% at the implant level. CHAID decision tree analysis identified three predictors (history of treated periodontitis, absence of regular supportive peri-implant maintenance, and use of bone graft) for peri-implant mucositis and three predictors (smoking, absence of regular supportive peri-implant maintenance, and placement of ≥2 implants) for peri-implantitis. Conclusions Within the limitations of this study, CHAID decision tree analysis identified the most plausible risk indicators and provided two predictive models for use in a particular university setting that would allow early detection and ensure appropriate care and maintenance of patients at high risk of peri-implant diseases.

This study investigated whether a keratin hydrogel derived from wool enhances ossointegration of dental implants, using a cancellous bone model in sheep.Ten female sheep received one dental implant per hind leg in the distal femoral condyles. Test implants were coated with 1 mL of keratin hydrogel containing sulphonated keratin and hydroxyapatite; control implants remained uncoated; implants were not functionally loaded axially. Biomechanical stability was tested with resonance frequency analysis (RFA) at placement and euthanasia. Animals were sacrificed after 4 weeks and resin-embedded histomorphometry performed.Bone appeared denser and more mature around the keratin-treated test implants. Average % bone-implant contact was significantly increased for the test (58.1 ± 4.6 [SD]%) compared to control implants (34.4 ± 7.5%) (p = 0.01). RFA values were lower for control (76.5 ± 4.2 ISQ) than test implants (80.4 ± 1.4) after 4 weeks (p = 0.04).the increase in osseointegration found in this model suggests that keratin hydrogel has the potential to enhance the successful osseointegration of dental implants placed into poor quality bone. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2447-2454, 2018.

OBJECTIVE The objective of this study was to assess 1-year clinical success of one-piece zirconia implants compared with similar-design titanium implants, in the context of a novel protocol for implant distribution. MATERIALS AND METHODS Twenty-four edentulous participants were randomly allocated to one-piece titanium or zirconia implant group. Each participant received four implants in the maxilla (mid-palatal and three anterior crestal implants) and three implants in the mandible (mid-symphyseal and two bilateral distal implants). Conventional loading protocol was followed. Marginal bone remodeling and clinical success of implants were evaluated. The data were statistically analyzed, and risk predictors for implant failures were evaluated. RESULTS There was no significant difference in the survival rate between the two groups. In the mandible, the survival rate of titanium implants was 95.8% vs. 90.9% for the zirconia implants. The corresponding values in the maxilla were 71.9% and 55%, respectively. Three implants in the zirconia group fractured. Statistically significant less marginal bone loss was observed around titanium implants (0.18 mm) compared with the zirconia group (0.42 mm). The prediction model revealed a higher risk for implant failures in the maxilla (P < 0.0001). CONCLUSION The outcome of this study indicates caution before recommendation can be made for the use of single-piece zirconia implants for overdenture support. Their use should be limited to cases with proven allergy to titanium. This is mainly due to the increased bone loss and higher fracture rate observed for zirconia implants. Future biomaterial research should focus on producing surface characteristics on zirconia implants with outcomes similar to those established for the optimum osseointegration of titanium implants.

Background Titanium (Ti) implants have been used in the last four decades to replace missing teeth. Alternatives to Ti such as zirconia (Zr) may offer aesthetic advantages and be more acceptable to patients and clinicians concerned about Ti allergy but must show equivalent biological acceptability to Ti. Purpose The research aimed to investigate soft and hard tissue response to Ti and Zr implants in edentulous patients. Materials and Methods The research included 24 participants (Ti = 12, Zr = 12) restored with one-piece ball-abutment implants to support overdentures. Participants received four maxillary implants (two in the premolar alveolus, one off center in the alveolar midline, and one wide-diameter implant in the anterior median palate) and three mandibular implants (one in the midline and bilateral posterior implants). Results Success rates for both Ti and Zr implants were low, 67.9% for all alveolar implants and a survival rate of 50.0% for the palatal implants. Only 11 (52.4%) of 21 palatal implants survived the follow-up period. Peri-implant health was equivalent for Ti and Zr implants and showed no statistically significant changes from loading to the 1-year follow-up. Statistically significant differences were noted in radiographic bone level between Ti and Zr implants (p = .02), with Zr showing greater bone loss. Conclusions Although the failure rates with the one-piece Zr implants were higher than with the Ti ones, suggesting that the former's clinical usage as in this study cannot be recommended, it should be borne in mind that the fault may also lie with the novel prosthodontic design which was used.

Limited clinical research identifies prosthodontic perspectives of novel designs for zirconia implants supporting overdentures. Four pilot study participants were selected before a planned randomized clinical trial on zirconia implants supporting overdentures. Novel designs for maxillary four-implant overdentures (quadrilateral design) and mandibular three-implant overdentures (tripodal design) were used with 28 implants (maxilla, n = 16; mandible, n = 12). Four implants failed to achieve osseointegration prior to loading. At the 1-year follow-up appointment, all implants were surviving, the overdentures were in function, and there were no clinical signs of wear of the attachment system. A proof-of-principle for prosthodontic perspectives of a novel design using one-piece zirconia implants supporting maxillary and mandibular implant overdentures was achieved.

Bioactive substances may be used to enhance the rate and quantity of bone healing during osseointegration of titanium dental implants. A pilot observational study was undertaken to assess a novel keratin hydrogel in six adult sheep utilising the femoral condyles as the surgical site to assess osseointegration. Implants and osteotomy sites were coated with the keratin gel prior to implant placement (test implants) whereas the opposite knee received unmodified control implants in each animal. Fifty 3.5 mm × 7 mm Neoss dental implants were surgically implanted with a range of 3–5 Neoss dental implants placed per surgical site in each knee and allowed to heal for 5 days or 2, 4, 8, 12 and 16 weeks prior to the sheep being sacrificed. Of the 50 placed implants, 24 were used for this study and analysed via resin-embedded, undemineralised sections from test and control implants to assess the range of healing around the unloaded dental implants. These dental implants were analysed using histomorphometric methods for the best 3 consecutive threads on each side and the percentage of bone to implant contact (%BIC) was used to determine the degree of osseointegration between test and control dental implants at each time point. All implants appeared osseointegrated at the time of sacrifice. One each of the pairs of control implants at 2, 4 and 12 weeks demonstrated minimal integration histologically, with %BIC

The peri-implant diseases, namely peri-implant mucositis and peri-implantitis, have been extensively studied. However, little is known about the true magnitude of the problem, owing mainly to the lack of consistent and definite diagnostic criteria used to describe the condition. The objective of the present review is to systematically estimate the overall frequency of peri-implant diseases in general and high-risk patients.The systematic review is prepared according to the Meta-analysis of Observational Studies in Epidemiology statement. Studies were searched in four electronic databases, complemented by manual searching. The quality of the studies was assessed according to Strengthening the Reporting of Observational Studies in Epidemiology, and the data were analyzed using statistical software.Of 504 studies identified, nine studies with 1,497 participants and 6,283 implants were included. The summary estimates for the frequency of peri-implant mucositis were 63.4% of participants and 30.7% of implants, and those of peri-implantitis were 18.8% of participants and 9.6% of implants. A higher frequency of occurrence of peri-implant diseases was recorded for smokers, with a summary estimate of 36.3%. Supportive periodontal therapy seemed to reduce the rate of occurrence of peri-implant diseases.Peri-implant diseases are not uncommon following implant therapy. Long-term maintenance care for high-risk groups is essential to reduce the risk of peri-implantitis. Informed consent for patients receiving implant treatment must include the need for such maintenance therapy.

Longitudinal and cross sections of teeth from 17 species of the Recent dolphins (Delphinoidea and Inioidea) were examined under scanning electron microscope to study the arrangement and ultrastructure of dental tissues with reference to phylogenetic and functional constraints. For most species, enamel had a simple bi-layered structure of radial enamel and an outer layer of prismless enamel. The outer prismless layer varied from 5 to 30 % of enamel thickness. The enamel of Burmeister’s porpoise (Phocoena spinipinnis) was entirely prismless. The prisms had an open sheath; tubules and tuft-like structures were common at the enamel-dentine junction. Cetacean dentine was characterized by irregularly distributed dentinal tubules in a relatively homogenous dentinal matrix. Radial enamel was observed in all Delphinoidea and in the franciscana (Pontoporia blainvillei), whereas the Amazon river dolphin (Inia geoffrensis) had prisms organized in Hunter–Schreger bands. HSB in enamel are regarded as a device for resisting propagation of cracks. These may occur due to increased functional demands, possibly related to the hardness of the species diet. Simplification in tooth shape and reduced biomechanical demands plausibly explain the primitive radial organization among delphinoids and Pontoporia. The HSB structure in the Amazon river dolphin, similar to those of extinct archaeocetes, seems to have secondary functional implications. However, the distribution of HSB in more-basal odontocetes is too poorly known to judge whether the HSB of Inia are a retained plesiomorphic feature or convergence.

Introduction: The role of bacteria in the etiology of peri-implantitis has been reported in the literature. However, the influence of confounding factors on the disease remains unclear. The following case series discusses the presence of metal particles in diseased peri-implant mucosa.Case Series: Four patients with peri-implantitis underwent surgical peri-implant therapy and diode laser surface decontamination procedures. Peri-implant mucosa was excised under local anesthesia and samples were prepared for histology, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) to evaluate peri-implant tissues and identify deposits of foreign materials. Histologic examination demonstrated cellular fibrous connective tissue, with or without overlying stratified squamous epithelium. An inflammatory infiltrate consisting of a mixture of acute and chronic inflammatory cells was observed. Numerous deposits of granular foreign material were scattered within the connective tissue immediately below...

Objectives It is of imperative clinical significance to define a safe threshold for planned immediate implant restoration. The aim of this report was to evaluate the prognostic accuracy of resonance frequency analysis (RFA) measurements recorded at two different times (implant placement and 8-week post-implant placement) and to determine the optimal threshold value for predicting failure risk of immediately restored/loaded implants. Material and methods Twenty-eight 8- or 9-mm-diameter implants were placed in either a fresh molar extraction socket or a healed site. An electronic RFA device was used to record the implant stability quotients (ISQs) at implant placement surgery, 8 weeks and 1 year. Receiver operating characteristic (ROC) analysis was used to identify the optimal cut-off level. Sensitivity and specificity were also determined at the selected cut-off value. Results The area under the ROC curve for RFA at 8 weeks was 0.93 with a significant P-value (P = 0.001). The optimum cut-off value for detecting implant stability was 60.5 ISQ measured at 8 weeks, with sensitivity and specificity of 95.2% and 71.4%, respectively. Conclusions The implant stability measurements after 8 weeks showed a better accuracy in predicting implants that were at risk of failure than those taken at the time of implant placement.

Background In the replacement of missing teeth, a paradigm shift is currently observed with immediate implant placement and/or restoration, particularly in the aesthetic zone. In molar sites, however, anatomical, occlusal and biomechanical considerations remain deterrent factors influencing the outcome of this treatment paradigm. The aim of this report was to evaluate immediate placement and immediate restoration of strongly tapered wide-diameter implant in fresh mandibular molar extraction sockets. Methods Twenty-four 8- or 9-mm diameter implants were placed in either a fresh molar extraction socket or a healed site. All the implants received provisional crowns within 48 h. The provisional crowns were replaced with full ceramic crowns after 8 weeks of implant placement. Results The overall implant success rate after 1 year of service for the 24 implants in two treatment groups was 75%. Success rates were 83.3% and 66.7% for the delayed and immediate placement groups respectively, with no significant difference observed between the two groups (P = 0.35). Implant stability measurements identified the immediately placed implants to be more stable immediately after surgery than delayed placed implants. In contrast, the delayed placed implants were more stable after 8 week healing time. Conclusions The rehabilitation of single missing mandibular molars by immediately placed and restored wide-diameter implants was associated with a relatively high failure rate.

Objectives Two fractured one-piece experimental (commercially unavailable) zirconia implants were analyzed using scanning electron microscope (SEM) analysis to identify failure origins and aid in understanding the failure mechanisms. Modifications to the zirconia implant design are suggested to minimize such fracture incidences. Materials and methods Two zirconia implants fractured during the final torquing in the maxillary ridge using the prescribed hand torque wrench. The implants were subsequently retrieved and prepared for optical and SEM evaluation. Critical attention was given to the fractography (crack morphology) of the fractured implants to identify the fracture origin. Results Events related to initiation and propagation of the crack front could be detected from the morphology of the fractured surfaces. Unfavorable torque and bending forces applied on the implant during surgical placement and the inherent flaws in the material may have resulted in crack initiation and implant failure. Conclusions Caution must be exercised when placing zirconia implants in dense bone sites. Modification of surgical protocols for the intended implant site may be necessary. Improvement in design features specific to zirconia implants, and strict quality control during manufacture is essential to minimize the likelihood of fracture.

Well-ordered TiO2 nanotubes were prepared by the electrochemical anodization of titanium in an ethylene glycol electrolyte containing 1 wt% NH4F and 10 wt% H2O at 20 V for 20 min, followed by annealing. The surface morphology and crystal structure of the samples were examined as a function of the annealing temperature by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), respectively. Crystallization of the nanotubes to the anatase phase occurred at 450 °C, while rutile formation was observed at 600 °C. Disintegration of the nanotubes was observed at 600 °C and the structure vanished completely at 750 °C. Electrochemical corrosion studies showed that the annealed nanotubes exhibited higher corrosion resistance than the as-formed nanotubes. The growth of hydroxyapatite on the different TiO2 nanotubes was also investigated by soaking them in simulated body fluid (SBF). The results indicated that the tubes annealed to a mixture of anatase and rutile was clearly more efficient than that in their amorphous or plain anatase state. The in vitro cell response in terms of cell morphology and proliferation was evaluated using osteoblast cells. The highest cell activity was observed on the TiO2 nanotubes annealed at 600 °C. Copyright © 2010 John Wiley & Sons, Ltd.

Purpose: Degradation products of metallic biomaterials including titanium may result in metal hypersensitivity reaction. Hypersensitivity to biomaterials is often described in terms of vague pain, skin rashes, fatigue and malaise and in some cases implant loss. Recently, titanium hypersensitivity has been suggested as one of the factors responsible for implant failure. Although titanium hypersensitivity is a growing concern, epidemiological data on incidence of titanium-related allergic reactions are still lacking. Materials and methods: A computer search of electronic databases primarily MEDLINE and PUBMED was performed with the following key words: ‘titanium hypersensitivity’, ‘titanium allergy’, ‘titanium release’ without any language restriction. Manual searches of the bibliographies of all the retrieved articles were also performed. In addition, a complementary hand search was also conducted to identify recent articles and case reports. Results: Most of the literature comprised case reports and prospective in vivo/in vitro trials. One hundred and twenty-seven publications were selected for full text reading. The bulk of the literature originated from the orthopaedic discipline, reporting wear debris following knee/hip arthroplasties. The rest comprised osteosynthesis (plates/screws), oral implant/dental materials, dermatology/cardiac-pacemaker, pathology/cancer, biomaterials and general reports. Conclusion: This review of the literature indicates that titanium can induce hypersensitivity in susceptible patients and could play a critical role in implant failure. Furthermore, this review supports the need for long-term clinical and radiographic follow-up of all implant patients who are sensitive to metals. At present, we know little about titanium hypersensitivity, but it cannot be excluded as a reason for implant failure. To cite this article: Siddiqi A, Payne AGT, De Silva RK, Duncan WJ. Titanium allergy: could it affect dental implant integration? Clin. Oral Impl. Res. 22, 2011; 673–680 doi: 10.1111/j.1600-0501.2010.02081.x

Background: Conventional implant protocols advocate a two-stage technique with a load-free, submerged healing period. Recent studies suggest that immediate restoration of single implants may be a viable treatment option. Purpose: The purpose of this study was to evaluate prosthodontic and aesthetic peri-implant mucosal outcomes of immediately restored, Southern single-tapered implants in the anterior maxilla after 1 year. Materials and Methods: Participants (mean age: 43.25 years; range: 23–71 years) satisfying specified inclusion criteria were randomly allocated to conventional two-stage restoration (control group; n=14) and immediate restoration groups (test group; n =14) in a randomized controlled clinical trial. Tapered, roughened-surface Southern implants were placed using a standardized technique, and implant level bone impressions were made. Provisional screw-retained crowns, out of occlusion, were placed at second-stage surgery after 26 weeks for the conventional restoration group, and within 4 hours of implant placement for the immediate restoration group. Both groups had definitive screw-retained metal-ceramic crowns placed in occlusion 8 weeks later. Peri-implant mucosal response and papilla index were recorded 4 weeks after definitive crown placement to allow for mucosal maturation and at 1 year. Prosthodontic and aesthetic outcomes were assessed using established criteria. Results: There were no significant differences within, or between, the control and test groups for age, gender, bone quality or quantity, implant stability measurements at surgery, or implant length. There were no significant differences in the implant success rate as determined by radiographic bone loss and stability tests after 1 year. There were no significant differences in prosthodontic maintenance, peri-implant mucosal response, and papilla index between the two groups over 1 year. Conclusions: Tapered, roughened-surface implants immediately restored with single provisional crowns at surgery and definitive crowns 8 weeks later were as prosthodontically and aesthetically successful as conventionally restored two-stage implants during the first year of service. Restoring single implants immediately with screw-retained crowns is an efficient procedure, but the short-term outcome is by no means superior to a conventional two-stage approach.