3D-printed nanocomposite denture base resin: The effect of incorporating TiO2 nanoparticles on the growth of Candida albicans.

PURPOSE: To develop a biocompatible denture base resin/TiO2 nanocomposite material with antifungal characteristics that is suitable for 3D-printing denture bases. MATERIALS AND METHODS: TiO2 nanoparticles (NPs) with a 0.10, 0.25, 0.50, and 0.75 weight percent (wt.%) were incorporated into a commercially available 3D-printed resin material. The resulting nanocomposite material was analyzed using Lactate dehydrogenase (LDH) and AlamarBlue (AB) assays for biocompatibility testing with human gingival fibroblasts (HGF). The composite material was also tested for its antifungal efficacy against Candida albicans. Fourier transform infrared (FTIR) and Energy Dispersive X-ray Spectroscopy (EDX) mapping were conducted to assess the surface coating and the dispersion of the NPs. RESULTS: LDH and AB assays confirmed the biocompatibility of the material showing cell proliferation at a rate of nearly 100% at day 10, with a cytotoxicity of less than 13% of the cells at day 10. The concentrations of 0.10, 0.25, and 0.50 wt.% caused a significant reduction (p < 0.05) in the number of candida cells attached to the surface of the specimens (p < 0.05), while 0.75 wt.% did not show any significant difference compared to the control (no TiO2 NPs) (p > 0.05). FTIR and EDX analysis confirmed the presence of TiO2 NPs within the nanocomposite material with a homogenous dispersion for 0.10 and 0.25 wt.% groups and an aggregation of the NPs within the material at higher concentrations. CONCLUSION: The addition of TiO2 NPs into 3D-printed denture base resin proved to have an antifungal effect against Candida albicans. The resultant nanocomposite material was a biocompatible material with HGFs and was successfully used for 3D printing.

Virtual and augmented reality in dental education: The good, the bad and the better.

INTRODUCTION: Virtual reality and augmented reality (VR/AR) are becoming established technologies with a wide range of possibilities in various academic fields, including dentistry. The practice of dentistry encompasses a spectrum of skills and knowledge of anatomy, complex technical and clinical skills and sound academic understanding. This review aims to scope the current use of these technologies in dental education, explore their impact on teaching and learning and envisage their potential in this field. MATERIALS AND METHODS: The Cochrane Library, PubMed and EMBASE were searched. Cochrane Handbook was used to conduct this systematic review. Inclusion and exclusion criteria were applied; randomised control trials published in English in the last 10 years (2010-2020) were considered and screened independently by two authors. RESULTS: Fourteen of 524 studies were included and assessed. The majority of articles describing the use of VR/AR focused on an Undergraduate/General Dental Practitioner audience. Its use in Oral and Maxillofacial Surgery, Endodontics and Restorative dentistry was also described. There is evidence of motor skill acquisition using these systems which is comparative to that of traditional methods. CONCLUSION: The use of VR/AR is well established in dental education; most applications relate to undergraduate education as a useful adjunct to dental training. In this article, the breadth of learning in dental education using VR/AR was exploited providing an overview to aid dental education. VR/AR is a useful adjunct to conventional learning in dentistry. However, there are limitations preventing VR/AR widespread use and applications, such as lack of trials, standardisation and accreditation of systems/content.

The Use of Hydroxyapatite Loaded with Doxycycline (HADOX) in Dentoalveolar Surgery as a Risk-Reduction Therapeutic Protocol in Subjects Treated with Different Bisphosphonate Dosages.

Medication-related osteonecrosis of the jaw (MRONJ) is considered as a severe adverse side effect of specific drugs such as anti-resorptive and anti-angiogenic medications. Evidence suggests that MRONJ is linked to invasive dental procedures, mainly dentoalveolar surgery. Several preventive strategies to minimize the risk of developing MRONJ have been investigated. However, no investigation has been attempted to evaluate the therapeutic effect of local drug-delivery technology as a preventive strategy protocol. The aim of this study is to evaluate the efficacy of hydroxyapatite-containing doxycycline (HADOX) in rats with high-risk MRONJ development. All the rats used in this study were divided into seven groups. Six groups of rats out of seven were exposed to two different doses of antiresorptive drug therapy for four weeks before undergoing an upper incisor extraction. After 28 days, all the animals were euthanized, and the bone blocks were processed for histological and histomorphometrical evaluation. The histomorphometric analysis confirmed that newly formed bone (NFB) was present in all groups, with significant differences. NFB in the HADOX group treated with zoledronic acid at 4% showed (28.38; C.I. 22.29-34.48), which represents a significant increase compared to HA (15.69; C.I. 4.89-26.48) (p = 0.02). A similar pattern was observed in the HADOX group treated with zoledronic acid 8% ZA treatment (p = 0.001). Conclusions: HADOX did not inhibit any bone repair and reduced early inflammatory response. Hence, HADOX could promote bone healing in patients undergoing antiresorptive drug therapy.

Evaluation of Quality of Life in Adult Individuals With Cleft Lip and/or Palate.

OBJECTIVES: The purpose of the present study was to systematically review literature relating to the quality of life (QoL) in adult individuals with cleft lip and/or palate (CLP) and identify which aspect of QoL adults with CLP find to be the most problematic, in comparison to a general non-cleft population. DESIGN: Different databases were searched for this review including the Cochrane Central Register of Controlled Trials, Ovid MEDLINE and Embase. Five domains of QoL were identified to evaluate the overall results of these QoL measures. These domains were; physical function, physical pain, psychological implications and self-esteem, self-perception in relation to facial aesthetics, and social function. The studies included underwent critical appraisal and different types of bias were assessed based on the Cochrane handbook for systematic reviews of interventions. RESULTS: Ten studies were included in this review. The total number of participants was 541. The most common QoL measure for adults with CLP was Short-Form (SF-36). Seven studies out of 10 reported statistically significantly worse scores (P < 0.05) in the psychological implications and self-esteem domains of QoL in adults with CLP, indicating lower QoL in terms of these domains. The least affected QoL domain was physical function. A high heterogeneity was found among the studies, including variation in the QoL measures, types of orofacial clefts, types of treatment and comparison groups. CONCLUSION: The presence of CLP did seem to negatively affect the QoL for adults with CLP, mainly in terms of psychological implications and self-esteem.

A Systematic Review and Meta-Analysis of Complications Associated With Autogenous Diced Cartilage Wrapped in Fascia Used in Nasal Dorsum Augmentation.

BACKGROUND: Nasal dorsum augmentation is a highly challenging rhinoplastic procedure. Problems encountered in this surgery, such as residual humps, irregularities, and asymmetry, account for a significant number of revision rhinoplasties. OBJECTIVES: The aim of this meta-analysis was to assess complication rates and graft harvesting site morbidity and revision rates. METHODS: We carried out a systematic review of the literature for pertinent materials in PubMed/Medline and Google Scholar up to and including August 2020. In addition, the reference list of included studies was searched manually. The criteria used were those described in the PRISMA Declaration for performing systematic reviews. RESULTS: The initial search yielded 236 results. After 3 stages of screening, 16 papers (18 groups) were included in the systematic review and meta-analysis. Our results indicated that the total rates for the complications studied were as follows: graft resorption, 2.52%; insufficient augmentation, 3.93%; deviation (graft displacement), 1.77%; infection, 2.30%; irregularity, 1.36%; supra-tip depression, 1.13%; overcorrection, 3.06%; hematoma at recipient site, 1.36%; and visible bulging of the graft, 2.64%. The total rates for donor site hypertrophic scar and donor site hematoma were 2.64% and 3.58%, respectively. The rate of the revision surgery was 3.03%. CONCLUSIONS: Current findings suggest the overall complications and revision rates with the use of diced cartilage wrapped in fascia for dorsum augmentation were relatively low and this technique is a reliable treatment choice for patients with primary/secondary dorsum deficiencies. Further studies with larger sample sizes and long-term follow-ups, clearer definitions of complications, and objective measurements are warranted to draw reliable practical conclusions.

The role of antiresorptive drugs and medication-related osteonecrosis of the jaw in nononcologic immunosuppressed patients: A systematic review.

Medication related osteonecrosis of the jaw (MRONJ) is a severe condition affecting the jaws of patients exposed to specific drugs, and is primarily described in patients receiving bisphosphonate (BP) therapy. However, more recently it has been observed in patients taking other medications, such as the RANK ligand inhibitor (denosumab) and antiangiogenic drugs. It has been proposed that the existence of other concomitant medical conditions may increase the incidence of MRONJ. The primary aim of this research was to analyze all available evidence and evaluate the reported outcomes of osteonecrosis of the jaws (ONJ) due to antiresorptive drugs in immunosuppressed patients. A multi-database (PubMed, MEDLINE, EMBASE and CINAHL) systematic search was performed. The search generated twenty-seven studies eligible for the analysis. The total number of patients included in the analysis was two hundred and six. All patients were deemed to have some form of immunosuppression, with some patients having more than one disorder contributing to their immunosuppression. Within this cohort the commonest trigger for MRONJ was a dental extraction (n=197). MRONJ complications and recurrence after treatment was sparsely reported in the literature, however a total of fourteen cases were observed. The data reviewed have confirmed that an invasive procedure is the commonest trigger of MRONJ with relatively high frequency of post-operative complications or recurrence following management. However, due to low-quality research available in the literature it is difficult to draw a definitive conclusion on the outcomes analysed in this systematic review.

Effect of mouthguard design on retention and potential issues arising with usability in sport.

BACKGROUND/AIMS: Mouthguard retention could potentially increase an athlete's motivation to wear the device, due to potential improvements in physical comfort. The aim of this study was to examine the retentive properties of selected customised mouthguard designs, during normal conditions (dry) and within the presence of artificial saliva (wet). Additionally, the correlation between thickness and retention was investigated. MATERIAL AND METHODS: Six different custom mouthguard designs (MG1-MG6) reported in previous studies, were pressure-formed with 2 and 4 mm blanks accordingly. Thickness was measured 10 times at seven anatomical points and the mean (±SD) was recorded. A novel rig was fabricated to connect the mouthguards to a Hounsfield H10KS Tensometer, which was used to fully displace each device from the model at a constant rate of 50 mm/min. The test was repeated under both dry and wet conditions. RESULTS: Retention forces recorded at the anterior region demonstrated higher measurements under wet conditions than dry (P < 0.001). The total retention of the mouthguards was influenced by alterations in their design. Trend analysis indicated that 64% of MG retention could be explained by their thickness under dry conditions and 55% when wet. CONCLUSIONS: Design and thickness of mouthguards are key factors in retention. Mouthguard fabrication techniques should be considered in order to minimize dislodgment of the devices as well as potentially increasing the wearability of mouthguards during sport.

Improved method for skin reflectance reconstruction from camera images.

A improved spectral reflectance reconstruction method is developed to transform camera RGB to spectral reflectance for skin images. Rather than using conventional direct or two-step processes, we transform camera RGB to skin reflectance directly using a principal component analysis (PCA) approach. The novelty in our direct method (RGB to spectra) is the use of a skin-specific colour characterisation chart with spectra closer to human skin spectra, and a new database of skin reflectances to derive the PCA bases. The experimental results using the facial images of 17 subjects demonstrate that our new direct method gives a significantly better performance than conventional, two-step methods and direct methods with traditional characterization charts. This new spectral reconstruction algorithm is sufficiently precise to reconstruct spectral properites relating to chromophores and its performance is within the acceptable range for maxillofacial soft tissue prostheses (error < 3 ΔE*ab units).

Interventions for iatrogenic inferior alveolar and lingual nerve injury.

BACKGROUND: Iatrogenic injury of the inferior alveolar or lingual nerve or both is a known complication of oral and maxillofacial surgery procedures. Injury to these two branches of the mandibular division of the trigeminal nerve may result in altered sensation associated with the ipsilateral lower lip or tongue or both and may include anaesthesia, paraesthesia, dysaesthesia, hyperalgesia, allodynia, hypoaesthesia and hyperaesthesia. Injury to the lingual nerve may also affect taste perception on the affected side of the tongue. The vast majority (approximately 90%) of these injuries are temporary in nature and resolve within eight weeks. However, if the injury persists beyond six months it is deemed to be permanent. Surgical, medical and psychological techniques have been used as a treatment for such injuries, though at present there is no consensus on the preferred intervention, or the timing of the intervention. OBJECTIVES: To evaluate the effects of different interventions and timings of interventions to treat iatrogenic injury of the inferior alveolar or lingual nerves. SEARCH METHODS: We searched the following electronic databases: the Cochrane Oral Health Group's Trial Register (to 9 October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE via OVID (1946 to 9 October 2013) and EMBASE via OVID (1980 to 9 October 2013). No language restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: Randomised controlled trials (RCTs) involving interventions to treat patients with neurosensory defect of the inferior alveolar or lingual nerve or both as a sequela of iatrogenic injury. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by The Cochrane Collaboration. We performed data extraction and assessment of the risk of bias independently and in duplicate. We contacted authors to clarify the inclusion criteria of the studies. MAIN RESULTS: Two studies assessed as at high risk of bias, reporting data from 26 analysed participants were included in this review. The age range of participants was from 17 to 55 years. Both trials investigated the effectiveness of low-level laser treatment compared to placebo laser therapy on inferior alveolar sensory deficit as a result of iatrogenic injury.Patient-reported altered sensation was partially reported in one study and fully reported in another. Following treatment with laser therapy, there was some evidence of an improvement in the subjective assessment of neurosensory deficit in the lip and chin areas compared to placebo, though the estimates were imprecise: a difference in mean change in neurosensory deficit of the chin of 8.40 cm (95% confidence interval (CI) 3.67 to 13.13) and a difference in mean change in neurosensory deficit of the lip of 21.79 cm (95% CI 5.29 to 38.29). The overall quality of the evidence for this outcome was very low; the outcome data were fully reported in one small study of 13 patients, with differential drop-out in the control group, and patients suffered only partial loss of sensation. No studies reported on the effects of the intervention on the remaining primary outcomes of pain, difficulty eating or speaking or taste. No studies reported on quality of life or adverse events.The overall quality of the evidence was very low as a result of limitations in the conduct and reporting of the studies, indirectness of the evidence and the imprecision of the results. AUTHORS' CONCLUSIONS: There is clearly a need for randomised controlled clinical trials to investigate the effectiveness of surgical, medical and psychological interventions for iatrogenic inferior alveolar and lingual nerve injuries. Primary outcomes of this research should include: patient-focused morbidity measures including altered sensation and pain, pain, quantitative sensory testing and the effects of delayed treatment.

Diabetes mellitus: considerations for the dental practitioner.

UNLABELLED: The prevalence of diabetes is increasing significantly and, therefore, dental practitioners are having to manage diabetic patients on a more regular basis. Alongside the systemic effects on the various tissues and organs of the body, diabetes can adversely affect oral health and all clinicians should be aware of the issues that may arise. CLINICAL RELEVANCE: Dental practitioners are almost guaranteed to encounter both diagnosed and undiagnosed diabetic patients. It is therefore important that they are aware of the oral signs and symptoms of disease and the reciprocal relationship between oral health and glycaemic control, so that diabetic patients are managed accordingly.

Surgical outcomes of the surgical techniques following management of iatrogenic trigeminal nerve injuries: A systematic review.

Objective: To investigate the effectiveness of the microsurgical treatment in restoring full sensory recovery following trigeminal nerve injuries caused by iatrogenic oral and maxillofacial surgical interventions. Methods: A detailed search was conducted on the Cochrane central register of controlled trials, Medline and Embase. Clinical studies with at least twelve months of follow up were included and assessment of risks of bias was made using the Robbin I assessment tool. Results: Six studies were identified in the searches which include 227 patients. The lingual nerve was the most common injured nerve, followed by the inferior alveolar nerve. Third molar removal was the most frequent cause of nerve injury, followed by root canal treatment, pathology excision, coronectomy, orthognathic surgery, dental implants and then local anaesthetic injections. Overall, surgical interventions for nerve injuries showed neurosensory improvement postoperatively in the majority of patients. Conclusion: Direct neurorrhaphy is still the gold-standard technique when the tension at the surgical site is minimal. Promising results have been noted on conduit applications following traditional repair or grafting. Further research is needed on the efficacy of allografting and conduit applications in nerve repair.

Ibuprofen and/or paracetamol (acetaminophen) for pain relief after surgical removal of lower wisdom teeth.

BACKGROUND: Both paracetamol and ibuprofen are commonly used analgesics for the relief of pain following the surgical removal of lower wisdom teeth (third molars). In 2010, a novel analgesic (marketed as Nuromol) containing both paracetamol and ibuprofen in the same tablet was launched in the United Kingdom, this drug has shown promising results to date and we have chosen to also compare the combined drug with the single drugs using this model. In this review we investigated the optimal doses of both paracetamol and ibuprofen via comparison of both and via comparison with the novel combined drug. We have taken into account the side effect profile of the study drugs. This review will help oral surgeons to decide on which analgesic to prescribe following wisdom tooth removal. OBJECTIVES: To compare the beneficial and harmful effects of paracetamol, ibuprofen and the novel combination of both in a single tablet for pain relief following the surgical removal of lower wisdom teeth, at different doses and administered postoperatively. SEARCH METHODS: We searched the Cochrane Oral Health Group'sTrials Register (to 20 May 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 4); MEDLINE via OVID (1946 to 20 May 2013); EMBASE via OVID (1980 to 20 May 2013) and the metaRegister of Controlled Trials (to 20 May 2013). We checked the bibliographies of relevant clinical trials and review articles for further studies. We wrote to authors of the identified randomised controlled trials (RCTs), and searched personal references in an attempt to identify unpublished or ongoing RCTs. No language restriction was applied to the searches of the electronic databases. SELECTION CRITERIA: Only randomised controlled double-blinded clinical trials were included. Cross-over studies were included provided there was a wash out period of at least 14 days. There had to be a direct comparison in the trial of two or more of the trial drugs at any dosage. All trials used the third molar pain model. DATA COLLECTION AND ANALYSIS: All trials identified were scanned independently and in duplicate by two review authors, any disagreements were resolved by discussion, or if necessary a third review author was consulted. The proportion of patients with at least 50% pain relief (based on total pain relief (TOTPAR) and summed pain intensity difference (SPID) data) was calculated for all three drugs at both two and six hours postdosing and meta-analysed for comparison. The proportion of participants using rescue medication over both six and eight hours was also collated and compared. The number of patients experiencing adverse events or the total number of adverse events reported or both were analysed for comparison. MAIN RESULTS: Seven studies were included, they were all parallel-group studies, two studies were assessed as at low risk of bias and three at high risk of bias; two were considered to have unclear bias in their methodology. A total of 2241 participants were enrolled in these trials.Ibuprofen was found to be a superior analgesic to paracetamol at several doses with high quality evidence suggesting that ibuprofen 400 mg is superior to 1000 mg paracetamol based on pain relief (estimated from TOTPAR data) and the use of rescue medication meta-analyses. The risk ratio for at least 50% pain relief (based on TOTPAR) at six hours was 1.47 (95% confidence interval (CI) 1.28 to 1.69; five trials) favouring 400 mg ibuprofen over 1000 mg paracetamol, and the risk ratio for not using rescue medication (also favouring ibuprofen) was 1.50 (95% CI 1.25 to 1.79; four trials).The combined drug showed promising results, with a risk ratio for at least 50% of the maximum pain relief over six hours of 1.77 (95% CI 1.32 to 2.39) (paracetamol 1000 mg and ibuprofen 400 mg) (one trial; moderate quality evidence), and risk ratio not using rescue medication 1.60 (95% CI 1.36 to 1.88) (two trials; moderate quality evidence).The information available regarding adverse events from the studies (including nausea, vomiting, headaches and dizziness) indicated that they were comparable between the treatment groups. However, we could not formally analyse the data as it was not possible to work out how many adverse events there were in total. AUTHORS' CONCLUSIONS: There is high quality evidence that ibuprofen is superior to paracetamol at doses of 200 mg to 512 mg and 600 mg to 1000 mg respectively based on pain relief and use of rescue medication data collected at six hours postoperatively. The majority of this evidence (five out of six trials) compared ibuprofen 400 mg with paracetamol 1000 mg, these are the most frequently prescribed doses in clinical practice. The novel combination drug is showing encouraging results based on the outcomes from two trials when compared to the single drugs.

Systemic interventions for recurrent aphthous stomatitis (mouth ulcers).

BACKGROUND: Recurrent aphthous stomatitis (RAS) is the most frequent form of oral ulceration, characterised by recurrent oral mucosal ulceration in an otherwise healthy individual. At its worst RAS can cause significant difficulties in eating and drinking. Treatment is primarily aimed at pain relief and the promotion of healing to reduce the duration of the disease or reduce the rate of recurrence. A variety of topical and systemic therapies have been utilised. OBJECTIVES: To determine the clinical effect of systemic interventions in the reduction of pain associated with RAS, a reduction in episode duration or frequency. SEARCH METHODS: We undertook electronic searches of: Cochrane Oral Health Group and PaPaS Trials Registers (to 6 June 2012); CENTRAL via The Cochrane Library (to Issue 4, 2012); MEDLINE via OVID (1950 to 6 June 2012); EMBASE via OVID (1980 to 6 June 2012); CINAHL via EBSCO (1980 to 6 June 2012); and AMED via PubMed (1950 to 6 June 2012). We searched reference lists from relevant articles and contacted the authors of eligible trials to identify further trials and obtain additional information. SELECTION CRITERIA: We included randomised controlled trials (RCTs) in which the primary outcome measures assess a reduction of pain associated with RAS, a reduction in episode duration or a reduction in episode frequency. Trials were not restricted by outcome alone. We also included RCTs of a cross-over design. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data in duplicate. We contacted trial authors for details of randomisation, blindness and withdrawals. We carried out risk of bias assessment on six domains. We followed The Cochrane Collaboration statistical guidelines and risk ratio (RR) values were to be calculated using fixed-effect models (if two or three trials in each meta-analysis) or random-effects models (if four or more trials in each meta-analysis). MAIN RESULTS: A total of 25 trials were included, 22 of which were placebo controlled and eight made head-to-head comparisons (five trials had more than two treatment arms). Twenty-one different interventions were assessed. The interventions were grouped into two categories: immunomodulatory/anti-inflammatory and uncertain. Only one study was assessed as being at low risk of bias. There was insufficient evidence to support or refute the use of any intervention. AUTHORS' CONCLUSIONS: No single treatment was found to be effective and therefore the results remain inconclusive in regard to the best systemic intervention for RAS. This is likely to reflect the poor methodological rigour of trials, and lack of studies for certain drugs, rather than the true effect of the intervention. It is also recognised that in clinical practice, individual drugs appear to work for individual patients and so the interventions are likely to be complex in nature. In addition, it is acknowledged that systemic interventions are often reserved for those patients who have been unresponsive to topical treatments, and therefore may represent a select group of patients.

Effect of Different Solutions on the Colour Stability of Nanoparticles or Fibre Reinforced PMMA.

This study aimed to evaluate the colour stability of polymethyl methacrylate (PMMA) denture base reinforced with ZrO2 nanoparticles, E-glass fibres, and TiO2 nanoparticles at various concentrations over 180-day storage in Steradent™ (STD) denture cleaner or coffee (CF). A total of 130 disc-shaped specimens were fabricated at various filler concentrations and divided into four main groups to measure the colour changes. Groups Z, T, and E consisted of PMMA reinforced with ZrO2 nanoparticles, TiO2 nanoparticles, or E-glass fibre, respectively, while Group C consisted of PMMA specimens without filler served as the control group (n = 10). The three reinforced groups were further subdivided according to the filler content (n = 10) added to the PMMA (1.5%, 3.0%, 5.0%, and 7.0% wt.%). Half of the specimens were stored in STD, while the other half was stored in CF for 180 days. A Minolta Chroma Meter was used to measure the colour changes (ΔE) at 7, 30, 90 and then 180 days. The results were assessed using two-way repeated-measures analysis of variance (RM-ANOVA) along with Bonferroni post hoc tests at a p ≤ 0.05 significance level. Significant different colour changes (ΔΕ) were observed between all tested groups and across different time points. TiO2-reinforced PMMA in STD/CF showed the lowest colour stability, while the E-glass fibre-reinforced PMMA in STD/CF showed the highest colour stability. Furthermore, coffee appeared to have the greatest impact on the colour change in comparison to the SteradentTM. The results indicated that the filler type and concentration, type of solution, and length of storage all affected the colour stability of the tested specimens.

Two Gingival Cell Lines Response to Different Dental Implant Abutment Materials: An In Vitro Study.

Objectives: This study aimed to investigate the response of human gingival fibroblasts (HGFB) and human gingival keratinocytes (HGKC) towards different dental implant abutment materials. Methods: Five materials were investigated: (1) titanium (Ti), (2) titanium nitride (TiN), (3) cobalt-chromium (CoCr), (4) zirconia (ZrO2), and (5) modified polyether ether ketone (m-PEEK). Both cell lines were cultured, expanded, and seeded in accordance with the protocol of their supplier. Cell proliferation and cytotoxicity were evaluated at days 1, 3, 5, and 10 using colourimetric viability and cytotoxicity assays. Data were analysed via two-way ANOVA, one-way ANOVA, and Tukey's post hoc test (p < 0.05 for all tests). Results: There was a statistically significant difference in cell proliferation of HGKC and HGFB cells in contact with different abutment materials at different time points, with no significant interaction between different materials. There was a significant effect on cell proliferation and cytotoxicity with different exposure times (p < 0.0001) for each material. Cell proliferation rates were comparable for both cell lines at the beginning of the study, however, HGFB showed higher proliferation rates for all materials at day 10 with better proliferation activities with ZrO and m-PEEK (40.27%) and (48.38%) respectively. HGKC showed significant interactions (p < 0.0001) in cytotoxicity between different materials. Conclusion: The present in vitro assessment investigated the biocompatibility of different abutment materials with soft tissue cells (HGFB and HGKC). The findings suggest that m-PEEK and TiN are biologically compatible materials with human cells that represent the soft tissue and can be considered as alternative implant abutment materials to Ti and ZrO2, especially when the aesthetic is of concern.

In-Vitro Phenotypic Response of Human Osteoblasts to Different Degrees of Titanium Surface Roughness.

Objectives: This study aimed to investigate human osteoblast (HOB) responses towards different degrees of titanium (Ti) implant surface roughness. Methods: Four degrees of Ti surface roughness were investigated on a micrometer roughness scale: smooth (S: 0.08−0.1 µm), minimally rough (MM: 0.3−0.5 µm), moderately rough (MR: 1.2−1.4 µm), and rough (R: 3.3−3.7 µm). HOB cells were cultured, expanded, and maintained according to the supplier's protocol. Cell proliferation and cytotoxicity were assessed at day 1, 3, 5, and 10 using alamarBlue and lactate dehydrogenase colorimetric assays. Data were analyzed with one-way ANOVA, two-way ANOVA, and Tukey's post hoc test (p = 0.05 for all tests). Results: There was no significant difference in the cell proliferation or cytotoxicity of the HOB cells in contact with the different degrees of Ti surface roughness. There was, however, a significant time effect on cell proliferation (p < 0.0001) with different exposure durations for each roughness degree. Furthermore, a positive correlation (non-significant) between proliferation and cytotoxicity was observed for all investigated degrees of surface roughness. Conclusion: All investigated roughness degrees showed comparable HOB proliferation, with the MR surface presenting the highest percentage, followed by the R, MM, ad S, surfaces, respectively. The S surface showed the highest cytotoxic effect on HOBs; however, it did not reach the cytotoxic level suggested by the ISO for any medical device to be considered cytotoxic.

Human osteoblasts response to different dental implant abutment materials: An in-vitro study.

OBJECTIVES: This study aimed to investigate human osteoblasts (HOB) response towards different dental implant abutment materials. METHODS: Five dental implant abutment materials were investigated: (1) titanium (Ti), (2) titanium coated nitride (TiN), (3) cobalt chromium (CoCr), (4) zirconia (ZrO2), and (5) modified polyether ether ketone (m-PEEK). HOBs were cultured, expanded, and seeded according to the supplier's protocol (PromoCell, UK). Cell proliferation and cytotoxicity were evaluated at days 1, 3, 5, and 10 using Alamar Blue (alamarBlue) and lactate dehydrogenase (LDH) colorimetric assays. Data were analysed via two-way ANOVA, one-way ANOVA and Tukey's post hoc test (significance was determined as p < 0.05 for all tests). RESULTS: All the investigated materials showed high and comparable initial proliferation activities apart from ZrO2 (46.92%), with P% of 79.91%, 68.77%, 73.20%, and 65.46% for Ti, TiN, CoCr, and m-PEEK, respectively. At day 10, all materials exhibited comparable and lower P% than day 1 apart from TiN (70.90%) with P% of 30.22%, 40.64%, 37.27%, and 50.65% for Ti, CoCr, ZrO2, and m-PEEK, respectively. The cytotoxic effect of the investigated materials was generally low throughout the whole experiment. At day 10, the cytotoxicity % was 7.63%, 0.21%, 13.30%, 5.32%, 8.60% for Ti, TiN, CoCr, ZrO2, and m-PEEK. The Two-way ANOVA and Tukey's Multiple Comparison Method highlighted significant material and time effects on cell proliferation and cytotoxicity, and a significant interaction (p < 0.0001) between the tested materials. Notably, TiN and m-PEEK showed improved HOB proliferation activity and cytotoxic levels than the other investigated materials. In addition, a non-significant negative correlation between viability and cytotoxicity was found for all tested materials. Ti (p = 0.07), TiN (p = 0.28), CoCr (p = 0.15), ZrO2 (p = 0.17), and m-PEEK (p = 0.12). SIGNIFICANCE: All the investigated materials showed excellent biocompatibility properties with more promising results for the newly introduced TiN and m-PEEK as alternatives to the traditionally used dental implant and abutment materials.

Biological response of epithelial and connective tissue cells to titanium surfaces with different ranges of roughness: An in-vitro study.

OBJECTIVES: This study aimed to investigate how titanium (Ti) surface with different range roughness created by industrial machining influence the biological response of primary human gingival fibroblasts (HGFB) and keratinocytes (HGKC) in terms of cell proliferation and cytotoxicity. METHODS: Four Ti surfaces of different roughness ranges were investigated: smooth (S: 0.08-0.1 µm), minimally rough (MM: 0.3-0.5 µm), moderately rough (MR: 1.2-1.4 µm) and rough (R: 3.3-3.7 µm). Discs topography and surface roughness were evaluated by scanning electron microscopy (SEM) and non-contact profilometer. Both cell lines were cultured, expanded, and maintained according to their supplier's protocols. Cell proliferation and cytotoxicity were evaluated at days 1, 3, 5, and 10 using cell viability and cytotoxicity colorimetric assays. Data were analysed via two-way ANOVA, one-way ANOVA and Tukey's post hoc test (p = 0.05 for all tests). RESULTS: Both cell lines showed comparable initial proliferation activity of 70-86% for all the investigated roughnesses. HGKC showed better and higher proliferation % with S surface at all time points than all the other investigated surfaces which was significantly higher than MM at day 3 and higher than all the other investigated surfaces at day 5 and 10. On the other hand, HGFB exhibited the best proliferation with both MM and R surfaces with no significant differences from the other two surfaces (S and MR). Different surface roughnesses and exposure times showed significant effect on cell proliferation in both cell lines. Cytotoxicity for both cell lines was generally the highest on day 3, with the following order from highest to lowest: S (19.86%)> R> MR> MM for HGKC and MM (39.48%)> MR> S> R for HGFB. Different exposure times showed a significant effect on cell cytotoxicity in both cell lines and a significant effect of surface roughness in HGFB. SIGNIFICANCE: All investigated roughness levels were sufficiently biologically compatible with cells representative of the major population of the soft tissue surrounding dental implants. However, the S surface was most cytotoxic to HGKC, while the MM surface was most cytotoxic to HGFB cells.

Enhancing livelihoods and the urban environment: the local political framework for integrated organic waste management in Diadema, Brazil.

Drawing on a participatory study of integrated organic waste management, this article explores the local political barriers and preconditions for its implementation in Diadema, Brazil. Solid waste management in Brazil is embedded in and mediated by a political framework that is characterised by uneven power geometries. This article explores how the local political context affects the potential for integrated organic waste management in Diadema, paying particular attention to relations between stakeholders. The discussion addresses the contested nature of deliberative decision-making spaces and the need for pro-active socio-environmental policies. The findings underline the importance of a praxis of everyday public participation that goes beyond rhetoric.

Schwannoma presenting in the soft palate of a nine-year-old boy.

Swellings and tumours within the oral cavity are a common finding, however, benign intra-oral schwannoma or neurolemma is relatively uncommon, especially in younger patients. Involvement of the palate is a rare presentation although there have been a few reported cases relating to the lingual and other tissues. This paper reviews intra-oral schwannomas and presents a case of such a tumour of the soft palate in a paediatric patient and discusses the presenting features, differential diagnoses, along with the management of the condition.