Andrew Tawse-Smith | University of Otago (original) (raw)

Papers by Andrew Tawse-Smith

INTRODUCTION: Biological complications around dental implants, including peri-implantitis and per... more INTRODUCTION: Biological complications around dental implants, including peri-implantitis and peri-implant mucositis, result from host-modulated response to bacterial biofilm. Current treatment approaches for these conditions do not adequately decontaminate implant surfaces and instrumentation is likely to damage the implant surfaces. OBJECTIVE: The aim of this study was to evaluate the bactericidal effect of laser diode irradiation (GaAlAs 810 nm) on biofilms formed in vivo on titanium surfaces, and to determine optimal laser parameters for disinfection. Ten participants wore an intraoral appliance each containing six titanium discs (Ra = 0.5) for 96 hours to generate multispecies biofilms. Discs were irradiated (ex vivo) with a range of diode laser outputs. Discs were stained with fluorescent viability dyes and examined by confocal laser-scanning microscopy and by scanning electron microscopy. After 96 hours, biofilms containing various bacterial morphotypes covered the entire disc surfaces. RESULTS: Diode laser irradiation resulted in a dose-dependent bactericidal effect with maximal antimicrobial efficacy at = 75 J/cm2. At this setting, no viable bacteria were evident, however cellular remnants and intracellular matrix were apparent. No damage to the titanium surface was evident following exposure to = 150 J/cm2. CONCLUSION: Diode laser irradiation effectively kills natural biofilms without damage to the titanium surface but the consequences of non-viable biofilm remnants on tissue healing remains to be determined.

Journal of dental and craniofacial research, Apr 16, 2018

Journal Odontológico Colegial, Jun 15, 2013

Objetivo: Determinar la asociacion entre el estado de salud oral de adolescentes entre 11-14 anos... more Objetivo: Determinar la asociacion entre el estado de salud oral de adolescentes entre 11-14 anos y la percepcion de la calidad de vida medida mediante el instrumento CPQ11-14. Metodos: Se realizo un estudio cuali-cuantitativo, descriptivo de corte transversal. Se valido el instrumento CPQ11-14 ,elaboracion del instructivo para los examinadores y anotadores del indice DAI y COP-S, con el proposito de unificar criterios de diagnostico y de registro; para la prueba piloto se tomo una muestra por conveniencia de 22 adolescentes del Colegio Departamental de Cundinamarca del municipio de Zipaquira. Los adolescentes diligenciaron el cuestionario del instrumento CPQ11-14 y se les realizo el examen clinico para el indice DAI y COP-S, se estandarizaron los examinadores de la fase II de la investigacion frente a un experto. Resultados: Se obtuvo un kappa de 1,0 para el COP-S y 0,76 para el indice DAI. Dentro de los hallazgos mas importantes en la poblacion estudio en cuanto a su percepcion de calidad de vida fue que el 31,8 % de los adolescentes han evitado sonreir cuando estan rodeados de sus companeros y se sienten timidos y avergonzados por su boca, el indice DAI fue de nivel 1: 36.4% (n=8), 2: 31.8% (n=7), 3: 22.7% (n=5) y 4: 9.1% (n=2) para la necesidad de tratamiento ortodontico y el indice COP-S fue de 55. Conclusion: Se encontro una asociacion significativa entre la condicion de salud oral de los adolescentes y su calidad de vida. Palabras claves: Calidad de vida, adolescentes, estetica dental, maloclusion.

Journal of Periodontal Research, Nov 7, 2015

Several clinical trials describe the effectiveness of xenogeneic collagen matrix (XCM) as an alte... more Several clinical trials describe the effectiveness of xenogeneic collagen matrix (XCM) as an alternative option to surgical mucogingival procedures for the treatment of marginal tissue recession and augmentation of insufficient zones of keratinized tissue (KT). The aim of this systematic review and meta-analysis was to evaluate the clinical and patient-centred outcomes of XCM compared to other mucogingival procedures. Applying guidelines of the Preferred Reporting Items for Systematic Reviews and Meta analyses statement, randomized controlled trials 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 analysed using statistical software. A total of 645 studies were identified, of which, six trials were included with 487 mucogingival defects in 170 participants. Overall meta-analysis showed that connective tissue graft (CTG) in conjunction with the coronally advanced flap (CAF) had a significantly higher percentage of complete/mean root coverage and mean recession reduction than XCM. Insufficient evidence was found to determine any significant differences in width of KT between XCM and CTG. The XCM had a significantly higher mean root coverage, recession reduction and gain in KT compared to CAF alone. No significant differences in patient's aesthetic satisfaction were found between XCM and CTG, except for postoperative morbidity in favour of XCM. Operating time was significantly reduced with the use of XCM compared with CTG but not with CAF alone. There is no evidence to demonstrate the effectiveness of XCM in achieving greater root coverage, recession reduction and gain in KT compared to CTG plus CAF. Superior short-term results in treating root coverage compared with CAF alone are possible. There is limited evidence that XCM may improve aesthetic satisfaction, reduce postoperative morbidity and shorten the operating time. Further long-term randomized controlled trials are required to endorse the supposed advantages of XCM.

Clinical Implant Dentistry and Related Research, Feb 13, 2022

BackgroundNonsurgical treatment of peri‐implantitis may help in reducing microbial load and infla... more BackgroundNonsurgical treatment of peri‐implantitis may help in reducing microbial load and inflammatory parameters. The potential clinical benefits of using different treatment approaches, in the initial nonsurgical treatment phase, particularly the airflow, are still not clear. The aim of this systematic review and meta‐analyses was to evaluate the outcomes of nonsurgical treatment of peri‐implantitis using airflow method in terms of changes in periodontal parameters, peri‐implant marginal bone level, postoperative pain/discomfort, and patient satisfaction.MethodsElectronic databases were searched to identify randomized controlled trials (RCTs) that compared airflow with mechanical debridement using ultrasonic/curettes. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool. Data were analyzed using a statistical software program.ResultsA total of 316 studies were identified, of which, five RCTs with 288 dental implants in 174 participants were included. Overall meta‐analysis showed more reduction in probing pocket depths at 1–3 months (mean difference [MD] −0.23; 95% confidence interval [CI] −0.50–0.05; p = 0.10) and 6 months (MD −0.04; 95% CI −0.34 to 0.27; p = 0.80) in favor of airflow, but the difference was not statistically significant. The use of airflow was associated with significant reduction in bleeding on probing and increase in peri‐implant mucosal recession. The differences in plaque score, peri‐implant marginal bone level changes, and patient reported outcomes between airflow and mechanical debridement were not statistically significant.ConclusionsThe short‐term clinical and radiographic outcomes following nonsurgical treatment of peri‐implantitis using airflow or mechanical debridement were comparable. The airflow has short‐term positive effects on reducing bleeding on probing. Further evidence from RCTs are still required to substantiate the current findings.

Clinical Implant Dentistry and Related Research, Feb 14, 2019

Background: Single implant crowns have become the preferred rehabilitation treatment option for r... more 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.

International Journal of Prosthodontics and Restorative Dentistry

However, a very common surface treatment with MMA monomer was not included. Another study 7 used ... more However, a very common surface treatment with MMA monomer was not included. Another study 7 used surface treatments of MMA, sanding and APA and tested the shear bond strength (SBS) and showed that the latter two showed significantly increased SBS compared to MMA. The current research has provided some good evidence but there is a limit to the conclusions that can be reached and shows the need for future research. Therefore, the aim of this study was to perform a systematic review that provides an overview of the current literature on the most efficient surface treatment method for repairing 3D printed dentures compared to conventional dentures and CAD/CAM milled dentures.

Oral, Apr 3, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

International Journal of Dentistry

Background and Objective. Several risk factors have been implicated in onset and development of p... more Background and Objective. Several risk factors have been implicated in onset and development of peri-implant diseases. The impact of these factors, however, remains controversial across the different clinical settings and populations. The aim of this retrospective study was to evaluate the risk factors for peri-implant diseases among an Emirati population. Methods. A retrospective analysis of patients aged ≥18 years and having dental implants placed at Dubai Health Authority in 2010. Relevant information related to systemic-, patient-, implant-, site-, surgical- and prosthesis-related factors were collected. The strength of association between the prevalence of peri-implant mucositis and peri-implantitis and each variable was measured by chi-square analysis. A binary logistic regression analysis was performed to identify possible risk factors. Results. A total of 162 patients with 301 implant-supported restorations were included in the study. The age of the patients ranged between 1...

Journal of Periodontology, 2019

BackgroundFurther validation of the risk indicators / predictors for peri‐implant diseases is req... more BackgroundFurther 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.MethodsA 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.ResultsThe 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 l...

The International Journal of Prosthodontics, 2018

O sseointegration is a dynamic process that continues with time and contributes to the secondary ... more O sseointegration is a dynamic process that continues with time and contributes to the secondary stability of implants following insertion. Primary stability is a prerequisite for the development of secondary stability, 1 as relative micromotion beyond an acceptable biologic threshold during initial healing is detrimental to the formation of a quality bone-implant interface. 2-4 After initial healing and a period of remodeling, the bone-implant interface should reach an equilibrium with little changes in the bone level while the implants are providing their designated function. 1,5 It is therefore useful to have an objective and quantitative assessment of the stability of implants, which may enable determination of an optimal loading time and long-term monitoring of implant health. 6 Based on observations, osseointegration has been described to include three partially overlapping phases: (1) healing phase; (2) remodeling phase; and (3) steady/ equilibrium phase. 5 After implant placement, the first stage of healing consists of formation of a hematoma and circulatory changes due to a cascade of chemical products that function as mediators, acting on vessels and surviving cells, as well as attracting cells from blood and surrounding tissue. There are also local changes in pH, oxygen tension, growth factors, and other biochemical substances. The second stage Purpose: To assess any correlations between resonance frequency analysis (RFA) and other clinical measurements, namely changes in marginal bone level. Materials and Methods: A systematic review was performed to investigate the relationship between RFA and changes in marginal bone level. Clinical studies published up to May 1, 2018, were searched in electronic databases, including PubMed/MEDLINE, Embase, and Cochrane, using the following MeSH terms: resonance frequency analysis; implant stability quotient; RFA; and ISQ, in combination with marginal bone level; marginal bone loss; and marginal bone resorption. Results: A total of 62 articles were included in this review after all abstracts and full-text articles were examined according to the inclusion/exclusion criteria. The Results and Discussion sections of investigations reporting both marginal bone level changes and RFA measurements were presented. Relevant findings regarding relationships between RFA and bone quality or insertion torque were also summarized. Most articles reported an overall increase in ISQs over the observation time; however, contradictory findings were found regarding the relationships between RFA measurements, marginal bone loss, and other parameters. Conclusion: A definitive conclusion could not be made, as mixed results were found in the few articles that reported significant associations and correlations between RFA measurements and bone loss, while others concluded the opposite. Heterogeneity between the studies further complicated interpretation. Longitudinal RFA measurements may still be valuable for evaluating implant stability when applied as a supplementary tool to radiographic assessments and other clinical examinations.

Journal of Prosthetic Dentistry, 2002

The International journal of prosthodontics

Journal of the International Academy of Periodontology, 2001

The aim of this study was to assess the effects on the gingiva when an experimental palatal acryl... more The aim of this study was to assess the effects on the gingiva when an experimental palatal acrylic removable appliance, was worn for 3 weeks. Clinical parameters were reassessed after a 3 week recovery period when the appliance was no longer worn. The appliance design featured a base plate on the right side which extended to the gingival margin, but which on the left, was relieved from the gingival margin by 6mm. Plaque index, gingival index, and probing depth were recorded on days 0, 7, and 21, and at day 42. Results indicated that there was increasing gingival inflammation in the right palatal gingiva by day 7, and this became worse by day 21. Statistically significant differences in gingival inflammation were evident when right and left sides were compared at day 7 and 21, although there were no significant differences in plaque accumulation during this period. Probing depth measurements also increased significantly on the right side by day 21. All these gingival changes reverse...

Clinical Implant Dentistry and Related Research

Dentistry Journal

Alveolar ridge preservation (ARP) reduces dimensional changes following tooth extraction. We eval... more Alveolar ridge preservation (ARP) reduces dimensional changes following tooth extraction. We evaluated the changes in alveolar ridge dimensions after ARP using bone substitutes and collagen membranes. Objectives included the tomographic evaluation of sites prior to extraction and six months after ARP and the assessment of the extent ARP preserved the ridge and reduced the need for additional augmentation at the time of implant placement. A total of 12 participants who underwent ARP in the Postgraduate Periodontics Clinic (Faculty of Dentistry) were included. Cone beam computed tomography images were used to retrospectively assess 17 sites prior to and six months after dental extraction. Alveolar ridge changes were recorded and analysed using reproducible reference points. The alveolar ridge height was measured at buccal and palatal/lingual aspects, whilst width was measured at crestal level, 2 mm, 4 mm and 6 mm below the crest. Statistically significant changes were found in alveola...

Clinical and Experimental Dental Research, 2019

Objectives: The aim of this study was to evaluate by light microscopy analysis the effect of the ... more Objectives: The aim of this study was to evaluate by light microscopy analysis the effect of the use of miniaturised piezoelectric tips versus mini-five area specific curets on calculus removal and postoperative root surface alterations. Methods: A total of 20 extracted teeth were used. Two square surfaces (5×5 mm) were marked on each root surface with a diamond bur mounted on a high-speed handpiece. Before and after instrumentation, a series of magnified images (4.2×) of each experimental surface were taken with a standardized approach. According to a randomization list, the two surfaces on each sample were instrumented in a standardised fashion either with a mine-five curet or a slim piezoelectric tip. The images were processed using an imaging software. Data were summarised as means and standard deviations for the two outcomes (calculus and alterations.) at each time (pre and post) for both of the groups (manual and mechanical). Results: Both manual and mechanical instrumentation significantly reduced the calculus deposits (p < .001) without significant differences between the two groups. Both manual and mechanical treatments significantly increased alterations (p < .01). There was a statistically significant evidence of a greater increase in alterations from mechanical treatment. Conclusions: Slim mechanical piezoelectric tips and manual mini-five area-specific curets have similar effects on calculus removal. Manual instrumentation results in a more homogeneous postoperative root surface with less root alterations. K E Y W O R D S calculus, nonsurgical periodontal therapy, periodontitis, scaling and root planing 1 | INTRODUCTION Periodontitis is an infective disease provoked by an array of periodontal pathogens inducing dysregulation of immune and inflammatory responses in host periodontal tissues, causing periodontal attachment loss (Kornman,

Acta Scientific Dental Scienecs, 2021

Background: Over the recent decades, the society has become more socially and ethically more awar... more Background: Over the recent decades, the society has become more socially and ethically more aware and accountable for climate change and global warming. Much of the current literature agrees that the healthcare system is not sustainable with the growing demand that causes environmental strain, and its underlying economics. With growing evidence that overall health is greatly influenced by the health of our planet, there is utmost importance to question our current practices in dentistry. Aim: The aim of this study was to investigate the amount of waste produced in the removable prosthodontics clinics, its impact on the environment, and suggest sustainable alternatives. Materials and Methods: Undergraduate prosthodontics clinics at the Faculty of Dentistry, University of Otago, Dunedin, New Zealand were audited retrospectively to assess the amount of waste produced during the semester 2 of 2019. A total of 496 appointments were included during 6 th of July and 23 rd of October. Predetermined codes were used to represent the clinical armamentarium required for each stage of treatment so that a total carbon footprint could be calculated. Results: A carbon footprint emission of 0.02tCO 2 e was estimated to be produced within the second semester of the 4 th year removable prosthodontics clinic in 2019. The most commonly used items were paper towels for pre and post appointment wipe downs followed by gloves and masks. When categorised by weight and type of waste, the greatest proportions were from sterilising packaging which contained both plastic and paper components (19.8%), followed by rubber (18.2%) and plastics (17.5%). Conclusion: It is recommended that the dental school should establish a method to audit its use of energy, water, waste generation, and its carbon footprint to provide baseline measures to improve upon, and endeavour towards sustainable dentistry.

Single tooth replacement using an implant restoration is commonly done in the anterior maxilla. W... more Single tooth replacement using an implant restoration is commonly done in the anterior maxilla. While a screw-retained implant restoration with the screw access at the palatal side of the crown is preferred for the aesthetic and retrievability, this is not always possible when there is inadequate bone volume for ideal implant positioning. In this case, the use of angled or customised abutment with a cement-retained restoration or cross-pin is necessary. Alternatively, bone augmentation may be performed prior to implant placement to improve the implant position. All these approaches however, add cost and complexity to the treatment. The Co-AxisTM implant features an angled implant shoulder platform that allows correction of screw channel at the subcrestal level. This clinical case report describes the use of the Co-AxisTM implant to restore a missing maxillary right canine.