Use of polyvinyl siloxane impressions to monitor sub-5-µm erosive tooth wear on unpolished enamel.

STATEMENT OF PROBLEM: Whether polyvinyl siloxane impressions are capable of reproducing 5-µm changes on natural freeform enamel and potentially enabling clinical measurements of early surface changes consistent with wear of teeth or materials is unclear. PURPOSE: The purpose of this in vitro study was to investigate and compare polyvinyl siloxane replicas with direct measurements of sub-5-µm lesions on unpolished human enamel lesions by using profilometry, superimposition, and a surface subtraction software program. MATERIAL AND METHODS: Twenty ethically approved unpolished human enamel specimens were randomized to a previously reported cyclic erosion (n=10) and erosion and abrasion (n=10) model to create discrete sub-5-µm lesions on the surface. Low viscosity polyvinyl siloxane impressions were made of each specimen before and after each cycle and scanned by using noncontacting laser profilometry and viewed with a digital microscopy and compared with direct scanning of the enamel surface. The digital maps were then interrogated with surface- registration and subtraction workflows to extrapolate enamel loss from the unpolished surfaces by using step-height and digital surface microscopy to measure roughness. RESULTS: Direct measurement revealed chemical loss of enamel at 3.4 ±0.43 µm, and the polyvinyl siloxane replicas were 3.20 ±0.42 µm, respectively. For chemical and mechanical loss direct measurement was 6.12 ±1.05 µm and 5.79 ±1.06 µm for the polyvinyl siloxane replica (P=.211). The overall accuracy between direct and polyvinyl siloxane replica measurements was 0.13 +0.57 and -0.31 µm for erosion and 0.12 +0.99 and -0.75 µm for erosion and abrasion. Surface roughness and visualization with digital microscopy provided confirmatory data. CONCLUSIONS: Polyvinyl siloxane replica impressions from unpolished human enamel were accurate and precise at the sub-5-µm level.

Pediatric patients' reasons for visiting dentists in all WHO regions.

BACKGROUND: Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact are the four oral health-related quality of life (OHRQoL) dimensions (4D) or areas in which oral disorders impact pediatric patients. Using their dentists' assessment, the study aimed to evaluate whether pediatric dental patients' oral health concerns fit into the 4D of the Oral Health-Related Quality of Life (OHRQoL) construct. METHODS: Dentists who treat children from 32 countries and all WHO regions were selected from a web-based survey of 1580 international dentists. Dentists were asked if their pediatric patients with current or future oral health concerns fit into the 4D of the Oral Health-Related Quality of Life (OHRQoL) construct. Proportions of all pediatric patients' oral health problems and prevention needs were computed. FINDINGS: Data from 101 dentists treating children only and 523 dentists treating children and adults were included. For 90% of pediatric patients, their current oral health problems fit well in the four OHRQoL dimensions. For 91% of oral health problems they intended to prevent in the future were related to these dimensions as well. Both numbers increased to at least 96% when experts analyzed dentists´ explanations of why some oral health problems would not fit these four categories. CONCLUSIONS: The study revealed the four fundamental components of dental patients, i.e., the four OHRQoL dimensions (Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact) are also applicable for pediatric patients, regardless of whether they have current or future oral health concerns, and should be considered when measuring OHRQoL in the pediatric dental patient population.

Why Patients Visit Dentists - A Study in all World Health Organization Regions.

OBJECTIVE: The dimensions of oral health-related quality of life (OHRQoL) Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact are the major areas where patients are impacted by oral diseases and dental interventions. The aim of this study was to evaluate whether dental patients' reasons to visit the dentist fit the 4 OHRQoL dimensions. METHODS: Dentists (N = 1580) from 32 countries participated in a web-based survey. For their patients with current oral health problems, dentists were asked whether these problems were related to teeth, mouth, and jaws' function, pain, appearance, or psychosocial impact or whether they do not fit the aforementioned 4 categories. Dentists were also asked about their patients who intended to prevent future oral health problems. For both patient groups, the proportions of oral health problems falling into the 4 OHRQoL dimensions were calculated. RESULTS: For every 100 dental patients with current oral health problems, 96 had problems related to teeth, mouth, and jaws' function, pain, appearance, or psychosocial impact. For every 100 dental patients who wanted to prevent future oral health problems, 92 wanted to prevent problems related to these 4 OHRQoL dimensions. Both numbers increased to at least 98 of 100 patients when experts analyzed dentists' explanations of why some oral health problems would not fit the four dimension. For the remaining 2 of 100 patients, none of the dentist-provided explanations suggested evidence against the OHRQoL dimensions as the concepts that capture dental patients' suffering. CONCLUSION: Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact capture dental patients' oral health problems worldwide. These 4 OHRQoL dimensions offer a psychometrically sound and practical framework for patient care and research, identifying what is important to dental patients.

Retention of implant-supported overdentures at different implant angulations: comparing Locator and ball attachments.

OBJECTIVES: To assess the effect of implant angulation on the retention of two different attachment systems for implant-supported overdentures after a simulated fatigue period of 5.5 years. MATERIAL AND METHODS: Two test set-ups were constructed. A two-implant mandibular implant-supported overdenture design was simulated using acrylic resin blocks to support implant replicas (Model 1 and Model 2). The replicas were set up in the canine regions (22-mm inter-implant distance). In Model 1, the implants were parallel (0° to the vertical axis) and in Model 2 they were divergent (20° to the vertical axis). The Locator and the ball attachment systems were tested at both set-ups. A simulated fatigue period of 5.5 years that equated to 10,000 cycles of insertion and removal of the denture was used. Retention values for each attachment system at each angulation set-up were measured at baseline, every 500 cycles until 4000 cycles and then every 1000 cycles. RESULTS: After simulated fatigue, the retention for both systems at both set-ups reduced. The Locator system reduced from 108.9 to 20.2 N in the parallel set-up and from 82.3 to 17.3 N in the divergent set-up. For the ball system, the retention reduced from 56.2 to 46 N when parallel and from 45.7 to 40.7 N when divergent. CONCLUSION: Both attachment systems showed a significant reduction in retention after simulated fatigue at both parallel and divergent set-ups. The change in implant angulation caused a significant reduction in retention for the ball attachment system only, although this was still higher at the end of testing than the Locator attachment system. The Locators also had a significantly faster rate of loss of retention at both set-ups. Clinically, this may indicate that the ball attachments may perform better with divergent implants.

Effect of Model Variables on in vitro Erosion.

The aim of this study was to investigate the effects of tooth type (molar/premolar), tooth surface (buccal/lingual), smear layer or no smear layer, storage of specimens in deionised water, mode and speed of agitation, and rinsing method between cycles on mean step height loss and Knoop microhardness (KHN) change. Polished human enamel specimens embedded in acrylic resin were prepared from sound permanent molar and premolar tooth surfaces. A 0.3% (pH 3.2) solution of citric acid was used to erode the specimens, in a cycling procedure, consisting of 10 min immersion followed by rinsing in deionised water for 30 s with a spray bottle, for 5 cycles. The specimens were analysed with a non-contact white light profilometer and KHN. Molar teeth (148.99±24.49 KHN) and buccal surfaces (155.62±30.35 KHN) produced significantly less microhardness change compared to premolar (186.40±20.74 KHN) and lingual surfaces (179.76±23.21 KHN; p<0001). The effect of storage and rinsing showed little difference in mean step height loss (<1 µm) and microhardness change. With no smear layer a significantly lower mean step height loss and microhardness change (p<0.001) was observed. Agitation was performed with Orbital, Gyro and See-Saw rockers at 30, 40, 60, and 70 rpm. The mean step height loss was largest for See-Saw at 70 rpm (11.73±0.91 µm) and lowest for Orbital at 30 rpm (2.76±1.12 µm). A statistical difference was found between all types of agitation and speeds (p<0.001). In conclusion, this study has shown that the variables investigated here have a significant impact on the measurable outcome, highlighting the importance of accurate and detailed method sections.

Intrusion of supraerupted maxillary molar using a high interim restoration on the defective opposing tooth: a clinical report.

Wear, extraction, or fracture of all or part of a mandibular first molar can lead to the supraeruption of the opposing maxillary molar, resulting in occlusal interference and lack of restoration space. This report describes a method to gain sufficient vertical space for permanent restoration. A direct composite resin restoration was placed on the occlusal surface of a lower molar, intentionally making the interim restoration high and intruding the maxillary molar. After 6 weeks, the extruded tooth returned to the desired position, and functional occlusion was restored, enabling a ceramic restoration on the mandibular molar. No marked adverse sensory reaction was reported in this therapeutic process, and no deleterious signs were detected in the teeth, periodontium, or temporomandibular joints. The simple treatment type was effective, noninvasive, and time saving, while also preserving maximum tooth structures.

Frequency of Locator Legacy Insert Changes With Implant Overdentures in a UK Population.

PURPOSE: To determine the frequency of insert changes for combined maxillary and mandibular implant overdentures (IOD) using the Locator Legacy system. A secondary objective was to assess the survival of dental implants with IODs. MATERIALS AND METHODS: This retrospective audit reviewed clinical records with up to 12 years follow up from 785 patients who received IODs using the Locator system at a dental hospital. From these, 151 had a combined maxillary opposed by a mandibular IOD and from this, 37 had data retrieved using a minimum data set. The frequency of insert change was recorded and descriptive analysis was provided by means and standard deviations for continuous variables. Frequencies of categorical values were reported as percentages. RESULTS: 222 implants were placed on 21 men, 16 women with a mean age 67.5 years (SD 8.8). All patients were reviewed at least once. Maxillary and mandibular IODs experienced 1.9 (SD 2.0) and 1.2 (SD 1.2) mean insert changes per patient, respectively. The mean time (SD) between initial and first insert change for maxillary and mandibular IODs was 3.4 months (SD 3.2) and 6.4 months (SD 7.2) and between the first and second insert change was 9.9 months (SD 9.0) and 10.0 months (SD 8.3), respectively. Implant failure was 21.6% and 2.7% in the maxilla and mandible respectively. CONCLUSIONS: Clinicians should anticipate the first insert change around 3 months for maxillary IOD and 6 months for mandibular IOD. Subsequently, the second insert change to be around 10 months for both maxillary and mandibular IODs.

Pilot clinical study to evaluate the efficacy of a professionally delivered high fluoride varnish on erosive tooth wear in an in-situ model.

OBJECTIVES: The aim for this pilot study was to investigate the effect of a sodium fluoride varnish on step height measured by a profilometer from human enamel worn by healthy volunteers with a novel in situ/ex vivo erosion design. METHOD: Healthy volunteers aged 18-70 years wore a palatal splint containing 8 human enamel samples and underwent two 3-day treatment periods for 6 h a day with a varnish containing sodium fluoride at 22,600 ppm and the control with the same ingredients but without fluoride. Each splint contained 4 polished and 4 unpolished samples. The interventions were applied to the surface of the enamel samples in randomised order, removed after 6 h, then immersed ex-vivo in 1 %, pH 2.7 citric acid for 2 min, repeated 4 times a day, over 2 days. Measurements of enamel were assessed blindly by microhardness on day 2 and by non-contact laser profilometry on day 3 for the two treatments. RESULTS: 24 volunteers, 2 males and 22 females aged 27-54 years, were screened and recruited. The delta microhardness, from polished samples removed at the end of day 2, for the control and fluoride treatment was 95.7 (22.9) kgf/mm2 and 123.7 (28.9) kgf/mm2, respectively (p < .005). The mean (SD) step height for the control polished enamel surfaces was 3.67 (2.07) µm and for the fluoride varnish was 1.79 (1.01) µm (p < .0005). The control unpolished enamel surfaces had a mean 2.09 (1.53) µm and the fluoride varnish was 2.11 (1.53) µm but no statistical difference was detected. CONCLUSIONS: The results from this pilot study, utilizing an in-situ model where enamel was exposed to acid over the course of 2 days, demonstrated that a high fluoride varnish containing sodium fluoride at 22,600 ppm prevented erosive wear compared to a control on the polished enamel surfaces. CLINICAL SIGNIFICANCE: Intra-oral study demonstrated that a high fluoride varnish containing sodium fluoride at 22,600 ppm reduced erosive tooth wear.

Frequency of Four-dimensional Oral Health Problems across Dental Fields - a Comparative Survey of Slovenian and International Dentists.

OBJECTIVES: To compare the frequency of patients' oral health problems and prevention needs among Slovenian and international dentists with the aim to validate the four oral health-related quality of life (OHRQoL) dimensions across six clinical dental fields in all World Health Organization (WHO) regions. METHODS: An anonymous electronic survey in the English language was designed using Qualtrics software. A probability sampling for Slovenia and a convenience sampling strategy for dentist recruitment was applied for 31 countries. Dentists engaged in six dental fields were asked to categorize their patients' oral health problems and prevention needs into the four OHRQoL dimensions (Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact). Proportions of patients' problems and prevention needs were calculated together with the significance of Slovenian and international dentists' differences based on dental fields and WHO regions. RESULTS: Dentists (n=1,580) from 32 countries completed the survey. There were 223 Slovenian dentists (females: 68%) with a mean age (SD) of 41 (10.6) years and 1,358 international dentists (females: 51%) with a mean age (SD) of 38 (10.4). Pain-related problems and prevention needs were the most prevalent among all six dental fields reported by dentists; Slovenian (37%) and 31 countries (45%). According to Cohen, differences between Slovenia, the broader European Region, and 31 countries were considered non-significant (<0.1). CONCLUSION: According to the dentists' responses, the frequency of patients' oral health problems and prevention needs are proportionate between Slovenia and 31 countries, regionally and globally. The four OHRQoL dimensions can be considered universal across all dental fields.

The impact of e-training on tooth wear assessments using the BEWE.

OBJECTIVE: To investigate the impact of an e-training resource with the consistency of tooth wear scoring using the Basic Erosive Wear Examination (BEWE). METHODS: Gold standard (GS) BEWE scores were attained from a trained examiner using the photographic and dental cast records for three conveniently selected cases representing low, medium and severe tooth wear. Four successive cohorts of first year post-graduate students, (n = 76, mean age, 35.4 years) undertook a training exercise. Each was given written guidance on using the BEWE. Following e-training, scoring was repeated, and the results expressed as mean, confidence Intervals, (95% ci) and p-values (values <0.05 were considered statistically significant). RESULTS: The e-training resulted in a mean improvement in the agreement with the GS score by 15.6% and 15.3%, using the records of the medium and severe tooth wear cases, (cumulative BEWE scores of 13 and 15 respectively). Post-training reductions were reported, with the mean number of disagreements with the GS and the mean change in the size of disagreement with the GS scores with records for the medium and severe cases (p = 0.001 and p < 0.001). No significant difference was revealed for the low wear case. CONCLUSION: e-training resulted in significant improvements in scoring BEWE, compared to the gold standard. CLINICAL RELEVANCE: Online training resources can help provide training with the BEWE.

The prevalence of cervical tooth wear in patients with bruxism and other causes of wear.

PURPOSE: The aim of this study was to investigate the prevalence of cervical wear lesions in three groups of patients: bruxists, combined tooth wear, and controls. The hypothesis was that those subjects presenting with bruxism were more likely to develop cervical wear lesions. MATERIALS AND METHODS: Of 119 subjects, 31 were bruxists with a mean age 48.7 years [standard deviation (SD): 11.6]; 22 had combined wear, aged 43.5 years (14.2); and 66 controls aged 44.9 years (17.0). The clinical appearance of the tooth wear was used to recruit subjects to the bruxist and combined tooth wear groups. Control subjects were randomly selected from those attending for routine dental examination at two general dental practices. A tooth wear index (TWI) was used by two trained examiners to record the severity of wear in each group. RESULTS: There was a statistically significant difference between the controls and both the bruxist and combined tooth wear groups for wear on all surfaces (p < or = 0.001). There was no significant difference between the bruxist and the combined tooth wear group for wear on any surface. There was a statistically significant difference between the control group and both the bruxist and the combined tooth wear group for the severity of cervical wear (p < or = 0.005), but no difference between the bruxist and combined tooth wear groups. There was also no statistical difference in the number of cervical lesions between the groups. CONCLUSIONS: In this study, the likely cause of cervical tooth wear was multifactorial.

An in-situ pilot study to investigate the native clinical resistance of enamel to erosion.

OBJECTIVES: To investigate the differences in susceptibility of the surface of native and polished enamel to dietary erosion using an in-situ model. METHODS: Thirty healthy volunteers (n = 10 per group) wore mandibular appliances containing 2 native and 2 polished enamel samples for 30 min after which, the samples were exposed to either an ex-vivo or in-vivo immersion in orange juice for 5, 10 or 15 min and the cycle repeated twice with an hour's interval between them. Samples were scanned with a non-contacting laser profilometer and surface roughness was extracted from the data, together with step height and microhardness change on the polished enamel samples. RESULTS: All volunteers completed the study. For native enamel there were no statistical difference between baseline roughness values versus post erosion. Polished enamel significantly increased mean (SD) Sa roughness from baseline for each group resulting in roughness change of 0.04 (0.03), 0.06 (0.04), 0.04 (0.03), 0.06 (0.03), 0.08 (0.05) and 0.09 (0.05) µm respectively. With statistical differences between roughness change 45 min in-vivo versus 45 min ex-vivo (p < 0.05). Microhardness significantly decreased for each polished group, with statistical differences in hardness change between 30 min in-vivo versus 30 min ex-vivo (p < 0.05), 45 min in-vivo versus 30 min ex-vivo (p < 0.01), 45 min in-vivo versus 45 min ex-vivo (p < 0.01). CONCLUSIONS: The native resistance to erosion provided clinically is a combination of the ultrastructure of outer enamel, protection from the salivary pellicle and the overall effects of the oral environment. CLINICALTRIALS. GOV IDENTIFIER: NCT03178968. CLINICAL SIGNIFICANCE: This study demonstrates that outer enamel is innately more resistant to erosion which is clinically relevant as once there has been structural breakdown at this level the effects of erosive wear will be accelerated.

Measurement of surface roughness changes of unpolished and polished enamel following erosion.

OBJECTIVES: To determine if Sa roughness data from measuring one central location of unpolished and polished enamel were representative of the overall surfaces before and after erosion. METHODS: Twenty human enamel sections (4x4 mm) were embedded in bis-acryl composite and randomised to either a native or polishing enamel preparation protocol. Enamel samples were subjected to an acid challenge (15 minutes 100 mL orange juice, pH 3.2, titratable acidity 41.3mmol OH/L, 62.5 rpm agitation, repeated for three cycles). Median (IQR) surface roughness [Sa] was measured at baseline and after erosion from both a centralised cluster and four peripheral clusters. Within each cluster, five smaller areas (0.04 mm2) provided the Sa roughness data. RESULTS: For both unpolished and polished enamel samples there were no significant differences between measuring one central cluster or four peripheral clusters, before and after erosion. For unpolished enamel the single central cluster had a median (IQR) Sa roughness of 1.45 (2.58) µm and the four peripheral clusters had a median (IQR) of 1.32 (4.86) µm before erosion; after erosion there were statistically significant reductions to 0.38 (0.35) µm and 0.34 (0.49) µm respectively (p<0.0001). Polished enamel had a median (IQR) Sa roughness 0.04 (0.17) µm for the single central cluster and 0.05 (0.15) µm for the four peripheral clusters which statistically significantly increased after erosion to 0.27 (0.08) µm for both (p<0.0001). CONCLUSION: Measuring one central cluster of unpolished and polished enamel was representative of the overall enamel surface roughness, before and after erosion.

The role of erosion in tooth wear: aetiology, prevention and management.

Tooth wear is a universal experience. The cause is usually a combination of erosion, attrition and abrasion. Attrition usually presents with flattened incisal and occlusal tooth surfaces which accurately inter-digitate. Erosion from dietary or gastric acids forms smooth lesions which typically appear as cupped occlusal/incisal and concave buccal/facial surfaces. When combined with attrition or abrasion, acids have the potential to cause significant wear. Wear reduces the thickness of enamel exposing the underlying dentine and changing the colour from the white of enamel to yellow of dentine. Acids causing erosion originate from the stomach or from the diet. Gastric acid is associated with reflux disease and eating disorders. The frequency of acidic foods and drinks and how they are consumed is important in dietary erosion. The progression of tooth wear is recognised to be slow with periods of activity and inactivity. Although restorations can be indicated, prevention and monitoring remain important strategies in maintaining the life of the teeth.

Safety issues when using carbamide peroxide to bleach vital teeth--a review of the literature.

Hydrogen Peroxide is used to bleach discoloured teeth but since its introduction in the late nineteenth century there have been concerns about its safety and efficacy. This paper reviews the literature on hydrogen peroxide and carbamide peroxide and assesses if these products can be recommended for clinical use. The authors used a Medline search to find the literature for review and from these the findings were divided into laboratory, animal and human studies. In conclusion no dental treatment is without risk but from the evidence it seems that bleaching teeth is comparatively safe.

Team training at an outreach dental unit.

A cohort of eighty nine undergraduate dental students worked for one year on two clinics completing a total of 3901 days work. Most of this time (63%) was spent at a site with shared nursing support, but despite this another site with dedicated nursing support produced approximately the same output. Students and nurses preferred working as a team rather than sharing; 98% of the students completed a questionnaire on the role of dental nurses and the majority identified chairside assistance as being the most important contribution to the increased throughput of patients.

The suitability of head-of-implant and conventional abutment impression techniques for implant-retained three unit bridges: an in vitro study.

This study compares the accuracy of master casts produced from impressions of implants using an abutment or a head-of-implant technique. The method used a Tandem Scanning Confocal Microscope to measure the dimensions of the gap between master casts produced by the two impression techniques and a custom made bridge. The median gap of 14 microns (interquartile range 10-17.9 microns) on the non-screwed side of the abutment impression was greater than the median gap of 7.5 microns (5-17.6 microns) for the head-of-implant impression and this difference was statistically significant (P < 0.005). In addition, the median gap on the screwed down side of the abutment impression of 10 microns, (6.3-12.1 microns) was greater than that of the head-of-implant of 5.5 microns (0.0-8.0 microns) and this difference was also statistically significant (P < 0.001). The head-of-implant impression produced a more accurate fit than the conventional abutment impression.

Direct cores for vital teeth--materials and methods used to retain cores in vital teeth.

A core, or foundation restoration, is used to restore extensively damaged teeth to a form suitable for crown preparation. This literature review considers the range of materials which can be used for cores and the evidence for their suitability. The methods for their retention in vital teeth will be presented and appraised.

Direct core materials.

There are many materials that can be used for direct-placement cores. Although the scientific evidence is incomplete, some materials are better suited to this task than others. This article provides an overview of direct-placement core materials and highlights what clinicians should consider when assessing a new product.