Effects of simulated long-term exposure to bottled, neutral pH electrolyzed oxidizing water on the properties of denture base resins.

STATEMENT OF PROBLEM: Denture stomatitis can pose serious health risks, especially to older people. Chemical denture cleaning agents must be effective, yet not adversely affect the longevity of removable dentures. Ready-to-use (RTU) neutral pH electrolyzed oxidizing water (EOW) is an effective biocide against Candida albicans biofilms on denture resins, but the effects of daily disinfection with EOW on the physical and mechanical properties of resins have not been established. PURPOSE: The purpose of this in vitro study was to investigate the effects of simulated long-term exposure to RTU EOW on the color, surface characteristics, and flexural strength of denture base resins. MATERIAL AND METHODS: Heat-polymerized (HP), 3D printed (3D) and computer-aided design and computer-aided manufacture (CAD-CAM)-milled (CC) denture resin specimens (square: 20×20×3.3 mm; beam: 64×10×3.3 mm) were immersed in tap water (TW), RTU EOW (Neutral Anolyte ANK; Envirolyte; EOW), or a commercial denture cleaning tablet solution (Polident 3-Minute; Glaxo SmithKline; PD), mimicking a 5-minute once daily disinfection routine performed up to 3.0 years. Color and surface roughness were recorded (n=3, squares), and changes in color (∆E00) and surface roughness (∆Ra) were calculated. Flexural strength (n=12, beams) and surface hardness (n=18, beams) were measured with a universal testing machine. The fractured surfaces of specimens were examined by scanning electron microscopy and energy dispersive spectroscopy. Data were assessed by performing the Shapiro-Wilk or D'Agostino and Pearson normality tests. Two-way ANOVA or the Kruskal-Wallis test with a post hoc Tukey HSD or Dunn multiple comparisons (α=.05) was used for statistical analyses. RESULTS: No significant changes were found in either color or surface roughness for HP, 3D, and CC resins after 1.5-year and 3.0-year immersion in any of the agents (P>.05). The surface hardness of 3D resins reduced by 14% with TW and by 23% with EOW and PD at 3.0 years. The flexural strengths of all 3 resins were unaffected by 3.0-year immersion (P>.05). CONCLUSIONS: Simulated long-term immersion disinfection with RTU neutral pH EOW did not adversely affect the physical and mechanical properties of HP or CC denture resins.

Microbial Analysis of Obturators During Maxillofacial Prosthodontic Treatment Over an 8-Year Period.

The aim of the study was to investigate the microbial colonization (by Candida species, anaerobic and facultative anaerobic bacteria) of maxillary obturators used for the restoration of maxillary defects, including during radiotherapy.Retrospective cohort study.Fifteen patients requiring a maxillary obturator prosthesis had swabs of their obturators and adjacent tissues taken at different stages of their treatment over a period of 8 years.Identification of microbial species from the swabs was carried out using randomly amplified polymorphic DNA polymerase chain reaction (RAPD PCR) analysis, checkerboard DNA-DNA hybridization, CHROMagar Candida chromogenic agar, and DNA sequencing.Candida species were detected in all patients and all patients developed mucositis and candidiasis during radiotherapy which was associated with an increase in colonization of surfaces with Candida spp., particularly C albicans. Microbial colonization increased during radiotherapy and as an obturator aged, and decreased following a reline, delivery of a new prosthesis, or antifungal treatment during radiotherapy.Microbial colonization of maxillary obturators was related to the stage of treatment, age of the obturator material, radiotherapy and antifungal medications, and antifungal treatment may be recommended if C albicans colonization of palatal tissues is greater than 105 colony-forming units per cm2 following the first week of radiotherapy.

Electrolysed oxidising water as a multi-purpose biocide in dental healthcare-A scoping review.

OBJECTIVES: The objective of this scoping review was to map evidence of electrolysed oxidising water (EOW) as a biocide for dental applications of relevance to older people and identify research gaps. BACKGROUND: EOW is an emerging, "green," and cost-effective biocide. There are no reviews on the landscape of EOW research as either an antiseptic or disinfectant in dental healthcare or its suitability for the oral healthcare of older people. MATERIALS AND METHODS: The review follows the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines. Database searches (Google Scholar, PubMed, Web of Science, Ovid, Scopus and Science Direct) were undertaken using MESH terms and Boolean operators with no date restrictions, to identify full-text, original reports published in English-language peer-reviewed journals. RESULTS: The search yielded 114 papers that met the inclusion/exclusion criteria. Dental applications of EOW include its use as an endodontic irrigant (39%); mouth rinse/surgical irrigant (21%); disinfectant for dental unit water lines (19%) and dental biomaterials (17%); and for antimicrobial efficacy, effects on oral tissues and on dental material properties. Most studies (83%) evaluated a single EOW formulation (acidic, moderately acidic or neutral) that was either generated at 'point-of-use' (POU; 72%), bottled ('ready-to-use', RTU; 24%) or from unspecified (3%) sources. Six reports evaluated storage-related parameters and 25 evaluated clinical applications; 89 were in vitro studies and one investigated the cost-effectiveness of POU EOW. CONCLUSIONS: Neutral-pH, EOW is effective as an antimicrobial agent without deleterious effects on oral tissues. However, research on the impact of storage conditions, anti-Candida biofilm efficacy and mechanism of action against yeasts, long-term effects on denture materials and cost-effectiveness is required to establish the suitability of EOW as a multipurpose biocide for dental healthcare, including infection-control requirements relating to older people.

The Role of Biofilms and Material Surface Characteristics in Microbial Adhesion to Maxillary Obturator Materials: A Literature Review.

BACKGROUND: Maxillofacial prosthetics includes restoration of maxillary defects resulting from resection of palate and nasosinus neoplasms with obturator prostheses which may be colonized by microorganisms and function as a reservoir of infection. Patients with neoplasms commonly also require radiotherapy that can result in changes in saliva quality and quantity and changes in the oral microbial flora. The altered flora, in individuals immunocompromised from cancer therapy, increases their risk of prosthesis-related infections. OBJECTIVES: In this review article, we explore microbial biofilms, their main components, mechanisms of microbial adhesion, and stages of biofilm development. We also discuss the different materials that are used for manufacturing maxillary obturators, their characteristic features, and how these can affect microbial adhesion. Furthermore, we shed some light on the factors that affect microbial adhesion to the surface of maxillary obturators including tissue proteins, protein adsorption, and the acquired enamel pellicle. CONCLUSIONS: The conclusions drawn from this literature review are that it is imperative to minimize the risk of local and systemic infections in immunocompromised patients with cancer having maxillary defects. It is also important to determine the role of saliva in microbial adhesion to obturator materials as well as develop materials that have a longer life span with surface characteristics that promote less microbial adhesion than current materials.

Personality, xerostomia and OHRQoL among 35-54-year-olds.

OBJECTIVE: Personality characteristics mean that people may interpret similar symptoms differently, complicating the measurement of self-reported oral health, and so we tested the hypothesis that controlling for aspects of personality makes a difference to the association between xerostomia and oral-health-related quality of life. MATERIAL AND METHODS: A cross-sectional study was conducted of a representative adult population sample in Dunedin (New Zealand). Data were collected on xerostomia, OHRQoL and personality characteristics, using (respectively) the 5-item Shortened Xerostomia Inventory (SXI), the OHIP-14 and the Positive and Negative Affect Schedule (PANAS). Negative binomial regression was used to model the association between the SXI and the OHIP-14 scores, and models with and without the PANAS score were compared. RESULTS: The participation rate was 51.3%, with complete OHIP-14 data available for 250 individuals (56.5% female). The SXI score (mean 6.9, sd 1.8) was strongly and positively associated with the OHIP-14 score (in both models), as was the PANAS negative affect score in the second model, which also explained slightly more of the observed variance than the first model. However, the difference in model deviance fell short of the amount required to reject the hypothesis that adding the PANAS variables to the model made a significant difference. CONCLUSIONS: Considering aspects of personality in investigating OHRQoL remains a theoretically important undertaking, but adjusting for it in analyses of associations between xerostomia and OHRQoL is unlikely to be necessary.

Interdisciplinary interface between fixed prosthodontics and periodontics.

Although periodontal factors do not usually have a direct effect on the survival of a fixed prosthesis, harmony between the prosthesis and the periodontium is critical otherwise esthetics, the longevity of the prosthesis and the periodontium will be compromised. A close interdisciplinary relationship between periodontics and prosthodontics is therefore necessary to avoid an unsatisfactory treatment outcome, requiring extensive and expensive retreatment. The design of the prosthesis, the number and quality of the abutment teeth, the preparation and the pontic, the occlusion and the material need to be considered when planning prosthodontic treatment. The location of the preparation margin and the contour and emergence profile of the prosthesis will influence the response of the gingival tissues to the prosthesis. Pontic design and cleansibility also contribute to the response of the gingival tissues as well as to the clinical and esthetic outcome. Even an optimal pontic design will not prevent inflammation of the mucosa adjacent to the pontic if pontic hygiene is not maintained by removal of plaque. Case selection and the patients' ability to carry out adequate oral hygiene are therefore essential for longevity of the prosthesis, and regular reviews provide an opportunity for early detection and treatment of failures.

Interdisciplinary periodontics: the multidisciplinary approach to the planning and treatment of complex cases.

Periodontics cannot be practiced in isolation as frequently many patients have multiple dental needs or medical health issues requiring management. In addition, pathology may manifest in the periodontal tissues, and the onset and progression of periodontitis can be affected by systemic conditions, such as diabetes, and vice versa. The focus of this volume of Periodontology 2000 is interdisciplinary periodontics, and the articles included discuss the interactions and the interrelationshipbetween periodontal tissues/periodontal diseases and endodontics, fixed prosthodontics, implant dentistry, esthetics, gerodontology, radiology, orthodontics, pediatric dentistry, oral and maxillofacial surgery, oral pathology, special needs dentistry and general medicine. Previous volumes of Periodontology 2000 have covered some of the interactions between periodontal diseases and other dental disciplines, especially implant dentistry, 'and the interaction between periodontal disease and systemic disease', but there has not been a volume on interdisciplinary periodontics. The intention therefore is to show how and why periodontics should be interdisciplinary, as well as the benefits of an interdisciplinary approach; in addition, the potential consequences of using a discipline in isolation are discussed.

The periodontal restorative interface: esthetic considerations.

Esthetic considerations are a significant contributing factor in the management of prosthodontic cases and an interdisciplinary approach is often necessary to achieve an optimal result. The visible soft-tissue architecture plays a key role in developing an esthetic smile. Furthermore, an understanding of the relationship between the restorative margin and the gingiva is important for long-term stability of the result. The gingival architecture and gingival health are important for ensuring optimal esthetics following prosthodontic work and close attention to both soft and hard tissues around the teeth, before, during and after restorative procedures, will greatly improve the likelihood of a successful outcome. Moreover, knowing the options available in periodontal plastic surgery is important in esthetic dentistry today. The relevant literature related to restorative and surgical procedures when performing esthetic dentistry are reviewed in this article, and different approaches are illustrated with appropriate cases to explain the treatment approach that was utilized to improve the esthetic appearance of the case.

How long will it last? The expected longevity of prosthodontic and restorative treatment.

With the Internet facilitating access to vast amounts of free information, dental practitioners face providing treatment for an increasingly informed public. However, the available content is not filtered, and it can be difficult for patients to discriminate between research-informed evidence and "glamorised" material of dubious origin. Patients reasonably expect a return for their investment and want to know how long their treatment will last. Clinicians have an obligation to inform their patients so that they can make reasoned decisions about treatment options. Longevity data are also informative for health agencies setting service schedules for publicly funded treatment, and for determining settlements by insurers such as ACC. Historically, much of the prosthodontic treatment performed in practice has relied heavily on dogma, low-level anecdotal evidence, and clinical case reports. This paper considers the literature on fixed and removable prosthodontic restorations and provides a critical review which can be used practically as the basis for informing patients, and to assist decision-makers in making fair and appropriate judgements.

Adhesion of Yeast and Bacteria to Oral Surfaces.

Colonization of surfaces in the human body by microorganisms is an early, essential, step in the initiation of infectious disease. We have developed in vitro assays to investigate interactions between yeast or bacterial cells and human tissues, fluids, or prostheses. Such assays can be used to identify the adhesins, ligands, and receptors involved in these interactions, for example, by determining which components of the microbe or human tissue/fluid interfere with adherence in the assay. The assays can also be applied to find ways of preventing adhesion, and subsequent disease, by investigating the effects of different conditions and added compounds on adherence in the in vitro assays. Here we describe assays for measuring adhesion of the oral yeast Candida albicans, a common commensal and opportunistic pathogen, or the bacterium Staphylococcus epidermidis, which is not normally pathogenic but is known to form biofilms on medical prostheses. The assays described belong to two approaches to investigating adhesion and biofilm formation: (i) retention at a fixed time point following liquid washes, and (ii) retention against a continuous flow of medium.

Clinical and Microbiological Evaluation of a Chlorhexidine-Modified Glass Ionomer Cement (GIC-CHX) Restoration Placed Using the Atraumatic Restorative Treatment (ART) Technique.

The aims of this study were to investigate the clinical effectiveness and patient acceptability of a modified glass ionomer cement placed using the atraumatic restorative treatment (ART) technique to treat root caries, and to carry out microbiological analysis of the restored sites. Two clinically visible root surface carious lesions per participant were restored using ART. One was restored with commercial glass ionomer cement (GIC) (ChemFil® Superior, DENTSPLY, Konstonz, Germany) which acted as the control. The other carious root lesion was restored with the same GIC modified with 5% chlorhexidine digluconate (GIC-CHX; test). Patient acceptability and restoration survival rate were evaluated at baseline and after 6 months. Plaque and saliva samples around the test and control restorations were collected, and microbiological analysis for selected bacterial and fungal viability were completed at baseline, and after 1, 3, and 6 months. In total, 52 restorations were placed using GIC and GIC-CHX in 26 participants; 1 patient was lost to follow-up. After reviewing the restorations during their baseline appointments, participants indicated that they were satisfied with the appearance of the restorations (n = 25, 96%) and did not feel anxious during the procedure (n = 24, 92%). Forty-eight percent (n = 12) of the GIC-CHX restorations were continuous with the existing anatomic form as opposed to six for the GIC restorations (24%), a difference which was statistically significant (p = 0.036). There was no statistically significant reduction in the mean count of the tested microorganisms in plaque samples for either type of restorations after 1, 3, or 6 months. Restoration of carious root surfaces with GIC-CHX resulted in higher survival rates than the control GIC. ART using GIC-CHX may therefore be a viable approach for use in outreach dental services to restore root surface carious lesions where dental services are not readily available, and for older people and special needs groups.

Cracking of porcelain surfaces arising from abrasive grinding with a dental air turbine.

PURPOSE: The purpose of this in vitro study was to evaluate porcelain cracking induced by abrasive grinding with a conventional dental air turbine and abrasive diamond burs. MATERIALS AND METHODS: Four commercially available porcelains were examined-Wieland ALLUX, Wieland ZIROX, IPS e.max Ceram, and IPS Empress Esthetic Veneering porcelain. Sixty discs of each porcelain type were fabricated according to manufacturer instructions, followed by an auto-glaze cycle. Abrasive grinding using fine, extra-fine, and ultra-fine diamond burs was carried out, using a conventional dental air turbine. The grinding parameters were standardized with regard to the magnitude of the force applied, rotational speed of the diamond bur, and flow rate of the water coolant. A testing apparatus was used to control the magnitude of force applied during the grinding procedure. The ground surfaces were then examined under scanning electron microscope. RESULTS: Cracking was seen for all porcelain types when ground with the fine bur. Cracking was not seen for specimens ground with the extra-fine or the ultra-fine bur. CONCLUSION: Wet abrasive grinding with a conventional dental air turbine and fine grit diamond burs has the potential to cause cracking in the four porcelain types tested. Similar abrasive grinding with smaller grit size particles does not cause similar observable cracking.

New Zealand dentists' use of gingival retraction techniques for fixed prosthodontics and implants.

OBJECTIVE: To identify the techniques most commonly used in New Zealand for gingival retraction for impressions of natural teeth and implants in fixed prosthodontics. DESIGN: Postal survey of a random sample of dentists METHODS: A questionnaire was mailed to all members of the New Zealand Dental Association (NZDA). Data were analysed using SPSS. RESULTS: The response rate was 51%. Veneer, crown and bridge treatments were routinely carried out by 89% of respondents, while implant treatment and/or implant-supported prostheses were provided by 65%. Around natural teeth, gingival retraction was mainly achieved with surgery (including electrosurgery, laser and rotary curettage) and/ or cord, by 82% of dentists. Cord with chemicals was used by 63% and plain cord by 37%. Gingival retraction around implants was used by 18%. Among the latter, the most popular gingival retraction method for use around implants was plain cord (used by 31%), while 25% used cord with chemicals. Another 23% reported using surgery as their means of gingival retraction around implants, while 19% reported using Expasyl (Pierre-Roland), and 2% reported using Magic Foam Cord (Dentsply), both of which are injectable matrices for gingival retraction. CONCLUSION: Dentists in New Zealand undertake a considerable amount of fixed prosthodontic and implant work. Gingival retraction around natural teeth is used commonly, while only a small number of participants report using it for implants. A surprising finding was the relatively high number of participants who reported using surgery for gingival retraction around natural teeth.

Tooth shade selection using a colorimetric instrument compared with that using a conventional shade guide.

OBJECTIVES: The aim of this study was to compare the colour matching ability of instrumental colorimetry with that of a conventional visual colour matching technique. SETTING: The study was conducted in a dental clinic at the University of Otago, School of Dentistry, New Zealand. MATERIALS AND METHODS: Three dentists with normal colour vision used a Vita Classical shade guide to determine the shade of the maxillary right central incisor of 10 randomly chosen individuals. The tooth colour of the same teeth was then determined with the Shade Vision colorimeter. The examiners were not aware of one another's shade selection and colorimetric readings. The shades selected were assigned numeric Delta E values for data compilation and statistical analysis, and the degree of examiner reliability was determined using the intraclass correlation coefficient (ICC). RESULTS: Analysis of the data indicated good overall interexaminer reliability for the Vita Classical shade guide (ICC = 0.62); however, the data showed poor agreement between the two shade selection techniques (ICC = 0.27). CONCLUSION: This study found no significant difference in the accuracy of shade selection when using either a conventional visual assessment technique or a colorimetric instrument. There was, however, some discrepancy when the two shade selection techniques were compared for shade selection of the same tooth. The clinical relevance of this difference is unclear, suggesting that additional research is needed to determine the clinical advantage of using a colorimeter.

Clinical Significance of the Use of Resonance Frequency Analysis in Assessing Implant Stability: A Systematic Review.

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.

Diurnal variation of intraoral pH and temperature.

OBJECTIVE/AIMS: The aim of this study was to measure continuously the intraoral pH and temperature of healthy individuals to investigate their diurnal variations. MATERIALS AND METHODS: Seventeen participants (mean age, 31±9 years) wore a custom-made intraoral appliance fitted with a pH probe and thermocouple for two sets of 24 h, while carrying out normal daily activities including sleep. The continuous changes in intraoral pH and temperature were captured using a sensor placed on the palatal aspect of the upper central incisors. The collected data were categorised into different status (awake and sleep) and periods (morning, afternoon, evening and night). Both quantitative and qualitative analyses were conducted. RESULTS: The intraoral pH change was found to show a distinctive daily rhythm, showing a 12-h interval between maximum (7.73) and minimum (6.6) pH values. The maximum and minimum values were found to repeat after 24 h. The mean pH over 48 h (two sets of 24 h) was found to be 7.27 (±0.74). There was significant difference found in pH when subjects were awake and asleep and different periods during the day (P<0.001). The mean intraoral temperature was 33.99 °C (±4.9), with less distinctive daily rhythm compared with pH. There was a significant difference found in temperature depending on the time of the day, except between morning and afternoon (P=0.78). CONCLUSION: Our results showed that there is a distinctive daily, circadian-like pattern in intraoral pH variation over a 24-h period, which has been considered as one of the risk factors in sleep-related dental diseases.

Adhesion of Yeast and Bacteria to Oral Surfaces.

Colonization of surfaces in the human body by microorganisms is an early, essential, step in the initiation of infectious disease. We have developed in vitro assays to investigate interactions between yeast or bacterial cells and human tissues, fluids, or prostheses. Such assays can be used to identify the adhesins, ligands, and receptors involved in these interactions, for example, by determining which components of the microbe or human tissue/fluid interfere with adherence in the assay. The assays can also be applied to finding ways of preventing adhesion, and subsequent disease, by investigating the effects of different conditions and added compounds on adherence in the in vitro assays.Here we describe assays for measuring adhesion of the oral yeast Candida albicans, a common commensal and opportunistic pathogen, or the bacterium Staphylococcus epidermidis, which is not normally pathogenic but is known to form biofilms on medical prostheses. The assays described belong to two approaches to investigating adhesion and biofilm formation: (1) retention at a fixed time point following liquid washes and (2) retention against a continuous flow of medium.

Interarch comparison of intraoral pH and temperature: a pilot study.

PURPOSE OF STUDY: The severity of tooth wear is known to have an association with intraoral pH and temperature depending on the site. OBJECTIVE: To compare the intraoral pH and temperature between the maxillary and mandibular arch. METHODS: Fourteen participants (mean age=25.8 years) wore a custom-made intraoral appliance fitted with a pH probe and thermocouple for 24 h while carrying out normal activities including sleep. All participants wore a maxillary appliance; four participants repeated the process and wore the mandibular appliance. Measurements were taken from the palatal aspect of the upper central incisors and lingual aspect of the lower canines. Both qualitative and quantitative statistical analyses were conducted. RESULTS: The mean intraoral pH from the maxilla was 7.32 (±0.52) and 7.07 (±0.26) for the mandible. During daytime, there was no statistical significance difference between the two arches (P=0.12). During sleep, there was a significant difference (P<0.001) between the mean pH of the maxilla, 7.0 (±0.46), and mandible, 6.46 (±0.31). The fluctuation patterns of pH and temperature from both arches were similar, but the maxilla showed more variations. The mean temperature from the mandible was slightly higher (36.18 °C (±0.96)) than the maxilla, 33.12 °C (±5.51) during daytime; however, there was no statistically significance difference in temperature between the arches during daytime (awake) or sleep (P=0.27). CONCLUSION: The results showed that there is significant difference in mean intraoral pH between the maxilla and the mandible during sleep, but not during the day and this difference may be associated variations in tooth wear between the arches.

Adhesion of yeast and bacteria to oral surfaces.

Colonization of surfaces in the human body by microorganisms is an early, essential, step in the initiation of infectious disease. We have developed in vitro assays to investigate interactions between yeast or bacterial cells and human tissues, fluids, or prostheses. Such assays can be used to identify the adhesins, ligands, and receptors involved in these interactions, for example by determining which components of the microbe or human tissue/fluid interfere with adherence in the assay. The assays can also be applied to finding ways of preventing adhesion, and subsequent disease, by investigating the effects of different conditions and added compounds on adherence in the in vitro assays. We describe six assays for measuring adhesion of the oral yeast Candida albicans, a common commensal and opportunistic pathogen, or the bacterium Staphylococcus epidermidis, which is not normally pathogenic but is known to form biofilms on medical prostheses. The assays described represent two approaches to investigating adhesion; retention at a fixed time point following liquid washes; and retention against a continuous flow of medium.