In-Vitro Tooth Cleaning Efficacy and Filament End Rounding of Different Manual Children's Toothbrushes.

PURPOSE: This in-vitro study aimed to investigate the cleaning efficacy of 18 different manual children's toothbrushes applying horizontal, vertical, and rotational movements, as well as to evaluate the rounding of their filament ends. MATERIALS AND METHODS: Models equipped with artificial teeth (coated with titanium dioxide) were brushed using a brushing machine with clamped manual children's toothbrushes. The machine carried out horizontal, vertical, and rotational movements for 1 min with a constant contact pressure of 100 g. The percentage of the area of titanium dioxide removed from the buccal, mesial, distal and total surfaces of the artificial teeth corresponded to the cleaning efficacy. To assess the filament design, a scanning electron microscope was used to check the morphology of the filaments which was scored with Silverstone and Featherstone scale. SPSS 22 was used for data analysis. RESULTS: The rotational and the vertical movements achieved the best cleaning efficacy with all tested toothbrushes. The vast majority of the tested toothbrushes had their poorest cleaning efficacy in the horizontal movement. Only a small part of the children's toothbrushes (3 out of 18) had a correct and acceptable proportion of rounded bristle ends. CONCLUSIONS: Based on the present results, it could be concluded that the cleaning efficacy of different manual children's toothbrushes varied considerably. The best cleaning efficacy was almost always observed for rotational and vertical movements.

Surface alterations and compound release from aligner attachments in vitro.

AIM: The aim of the present study was to assess the alterations in morphology, roughness, and composition of the surfaces of a conventional and a flowable composite attachment engaged with aligners, and to evaluate the release of resin monomers and their derivatives in an aqueous environment. METHODS: Zirconia tooth-arch frames (n = 20) and corresponding thermoformed PET-G aligners with bonded attachments comprising two composite materials (universal-C and flowable-F) were fabricated. The morphological features (stereomicroscopy), roughness (optical profilometry), and surface composition (ATR-FTIR) of the attachments were examined before and after immersion in water. To simulate intraoral use, the aligners were removed and re-seated to the frames four times per day for a 7-day immersion period. After testing, the eluents were analyzed by LC-MS/MS targeting the compounds Bis-GMA, UDMA, 2-HEMA, TEGDMA and BPA and by LC-HRMS for suspect screening of the leached dental material compounds and their degradation products. RESULTS: After testing, abrasion-induced defects were found on attachment surfaces such as scratches, marginal cracks, loss of surface texturing, and fractures. The morphological changes and debonding rate were greater in F. Comparisons (before-after testing) revealed a significantly lower Sc roughness parameter in F. The surface composition of the aligners after testing showed minor changes from the control, with insignificant differences in the degree of C = C conversion, except for few cases with strong evidence of hydrolytic degradation. Targeted analysis results revealed a significant difference in the compounds released between Days 1 and 7 in both materials. Insignificant differences were found when C was compared with F in both timeframes. Several degradation products were detected on Day 7, with a strong reduction in the concentration of the targeted compounds. CONCLUSIONS: The use of aligners affects the surface characteristics and degradation rate of composite attachments in an aqueous environment, releasing monomers, and monomer hydrolysates within 1-week simulated use.

Scoring facial attractiveness with deep convolutional neural networks: How training on standardized images reduces the bias of facial expressions.

OBJECTIVE: In many medical disciplines, facial attractiveness is part of the diagnosis, yet its scoring might be confounded by facial expressions. The intent was to apply deep convolutional neural networks (CNN) to identify how facial expressions affect facial attractiveness and to explore whether a dedicated training of the CNN is able to reduce the bias of facial expressions. MATERIALS AND METHODS: Frontal facial images (n = 840) of 40 female participants (mean age 24.5 years) were taken adapting a neutral facial expression and the six universal facial expressions. Facial attractiveness was computed by means of a face detector, deep convolutional neural networks, standard support vector regression for facial beauty, visual regularized collaborative filtering and a regression technique for handling visual queries without rating history. CNN was first trained on random facial photographs from a dating website and then further trained on the Chicago Face Database (CFD) to increase its suitability to medical conditions. Both algorithms scored every image for attractiveness. RESULTS: Facial expressions affect facial attractiveness scores significantly. Scores from CNN additionally trained on CFD had less variability between the expressions (range 54.3-60.9 compared to range: 32.6-49.5) and less variance within the scores (P ≤ .05), but also caused a shift in the ranking of the expressions' facial attractiveness. CONCLUSION: Facial expressions confound attractiveness scores. Training on norming images generated scores less susceptible to distortion, but more difficult to interpret. Scoring facial attractiveness based on CNN seems promising, but AI solutions must be developed on CNN trained to recognize facial expressions as distractors.

Cleaning performance of electric toothbrushes around brackets applying different brushing forces: an in-vitro study.

Throughout treatment with fixed orthodontic appliances, effective plaque control is crucial to maintaining dental health. This in-vitro study evaluated the cleaning performance of eleven different brush heads of seven electric toothbrushes (oscillating-rotating and sonic motions) and varying brushing forces around orthodontic brackets. Six Mini Diamond® Twin brackets were placed on black-stained front teeth. Teeth were coated with white titanium oxide and brushed in a machine six times for one minute with two different brushing forces (1 N and 1.5 N). Eleven different brush heads were evaluated (either oscillating-rotating or sonic movements). The teeth were scanned and planimetrically evaluated after brushing. Three detailed plaque areas (DPAs) were created: proximal (< 1 mm to bracket), mid-tier (1-2 mm to bracket), and distant (> 2 mm to bracket). The proportion of contaminated proximal, mid-tier, and distant surfaces (white regions) in relation to the respective DPA was calculated. Independent of brushing forces, places with a higher distance (> 2 mm) to the orthodontic bracket had the least amount of residual contamination, followed by areas with a minor (1-2 mm) and proximal distance (< 1 mm). In all of the brushes tested and for both estimated brushing forces, the region with the highest residual contamination was the proximal area. The brush heads of the Paro® Sonic toothbrush left the least amount of residual contamination. The cleaning performance of electric toothbrushes around brackets on upper incisors varied across the brushes examined. The proximal area has the most residual contamination. Furthermore, 9 out of 11 toothbrushes cleaned more successfully with 1.5 N than with 1 N brushing force.

Natural history of periodontal disease: The original Sri Lanka and Oslo studies.

Susceptibility to periodontal disease depends on individual factors within the host response to the bacterial challenge. The study of these factors requires longitudinal studies of an undisturbed development of the disease process. On the basis of the original longitudinal studies on the natural histology of periodontal disease staged in Sri Lanka and Oslo/Norway, several analyses of periodontal parameters and tooth status have been performed. The main findings were that in the first 20 years of complete absence of oral hygiene practices or preventive services attachment was lost at various rates. Three groups of subjects could be identified: rapidly progressing (RP) (8%), moderately progressing (MP) (81%), and subjects with no disease progression (NP) (11%). In the second two decades, the RP subjects have lost most of their teeth and no NP patients were identified anymore. The progression rate in these two decades was much slower, and the tooth mortality decreased. It could be predicted that subjects who had lost more than 2 mm at age 30 would not maintain a functional dentition at age 60. The corresponding control population in Oslo was used to study the influence of gingival inflammation on the initiation and progression of periodontal disease. The pattern and rates of attachment loss were identified in a population that was exposed to optimal and regular preventive services from age 3 onward. In the observation period of 26 years, it could be demonstrated that gingival inflammation varied little throughout adult life and always bleeding sites occurred consistently in 10% to 20%. The role of ongoing gingivitis in the pathogenesis of attachment loss was identified and also reflected stability whenever it was absent. Tooth mortality was only found in subjects with ongoing gingivitis. After 50 years of tooth age, 63% of the teeth were still maintained, while 99.8% were maintained after 50 years when gingival inflammation had been absent. Consequently, continuous gingivitis represented a risk factor for tooth loss.

Long-term stability of curve of Spee depth among orthodontically treated patients: A retrospective longitudinal study.

OBJECTIVE: The curve of Spee is deemed important characteristic of the dentition for a balanced occlusion and distribution of masticatory forces, while orthodontic levelling of an accentuated curve of Spee is generally included as a treatment goal for deepbite correction. However, relapse is often seen and can be problematic. METHODS: A retrospective longitudinal study of predominantly young patients with a deep curve of Spee, who had been treated orthodontically with 0.018"-slot Edgewise fixed appliances, was performed. The depth of the curve of Spee was digitally measured before treatment (T1), at debond (T2), and an average of 7 years post-debond (T3) and analysed statistically at 5%. RESULTS: A total of 157 patients were included (56.7% female; 11.6-year-old at T1), 16.6% of which were treated with premolars extractions. Non-extraction treatment reduced the curve of Spee at the first premolar from 1.87 mm (T1) to 0.22 mm (T2), which relapsed 0.12 mm (T3; P = .04). The respective depths for the second premolar were 2.0 mm (T1), reduced to 0.80 mm (T2). No significant relapse was seen for the second premolar (0.08 mm; P > .05) or the first permanent molar (0.06 mm; P > .05). No overall significant differences in absolute relapse were seen between extraction and non-extraction patients, but premolar extractions were associated with less clinically relevant relapse at the first molar (odds ratio 0.27; 95%-confidence interval 0.08-0.88; P = .003). CONCLUSION: Steep curves of Spee can be satisfactorily levelled orthodontically with satisfactory stability in the long term, while premolar extractions might be associated with less relapse.

Leaching from a 3D-printed aligner resin.

AIM: To quantitatively assess the degree of conversion and the water-leaching targeted compound from 3D-printed aligners. MATERIALS AND METHODS: 3D-printed aligners were made of photopolymerized resin (Tera Harz TC85A). The molecular structure and degree of conversion of the set resin were investigated by ATR-FTIR spectroscopy (n = 5). The aligners (n = 10) were immersed in double distilled water for 1 week at 37°C and the eluents were analysed using liquid chromatography/mass spectrometry methods (LC-ESI-MS/MS for urethane dimethacrylate [UDMA] and LC-APCI-MS/MS for bispenol-A [BPA]). RESULTS: The resin was composed of aliphatic vinyl ester-urethane monomers, with acrylate and/or methacrylate functionalization. The degree of conversion was estimated as to 83%. There was no detection of BPA in any of the assessed samples (0.25 µg/l). Quantifiable amounts of UDMA were detected in all the exposed samples, ranging from 29 to 96 µg/l. CONCLUSIONS: Although efficiently polymerized and BPA free, the great variability in the amount of UDMA monomer leached from the examined samples may raise concerns on potential health hazards after repeated intraoral exposure, which is indicated for this class of materials.

Artificial intelligence in medico-dental diagnostics of the face: a narrative review of opportunities and challenges.

OBJECTIVES: This review aims to share the current developments of artificial intelligence (AI) solutions in the field of medico-dental diagnostics of the face. The primary focus of this review is to present the applicability of artificial neural networks (ANN) to interpret medical images, together with the associated opportunities, obstacles, and ethico-legal concerns. MATERIAL AND METHODS: Narrative literature review. RESULTS: Narrative literature review. CONCLUSION: Curated facial images are widely available and easily accessible and are as such particularly suitable big data for ANN training. New AI solutions have the potential to change contemporary dentistry by optimizing existing processes and enriching dental care with the introduction of new tools for assessment or treatment planning. The analyses of health-related big data may also contribute to revolutionize personalized medicine through the detection of previously unknown associations. In regard to facial images, advances in medico-dental AI-based diagnostics include software solutions for the detection and classification of pathologies, for rating attractiveness and for the prediction of age or gender. In order for an ANN to be suitable for medical diagnostics of the face, the arising challenges regarding computation and management of the software are discussed, with special emphasis on the use of non-medical big data for ANN training. The legal and ethical ramifications of feeding patients' facial images to a neural network for diagnostic purposes are related to patient consent, data privacy, data security, liability, and intellectual property. Current ethico-legal regulation practices seem incapable of addressing all concerns and ensuring accountability. CLINICAL SIGNIFICANCE: While this review confirms the many benefits derived from AI solutions used for the diagnosis of medical images, it highlights the evident lack of regulatory oversight, the urgent need to establish licensing protocols, and the imperative to investigate the moral quality of new norms set with the implementation of AI applications in medico-dental diagnostics.

Using artificial intelligence to determine the influence of dental aesthetics on facial attractiveness in comparison to other facial modifications.

BACKGROUND: Facial aesthetics is a major motivating factor for undergoing orthodontic treatment. OBJECTIVES: To ascertain-by means of artificial intelligence (AI)-the influence of dental alignment on facial attractiveness and perceived age, compared to other modifications such as wearing glasses, earrings, or lipstick. MATERIAL AND METHODS: Forty volunteering females (mean age: 24.5) with near perfectly aligned upper front teeth [Aesthetic Component scale of the Index of Orthodontic Treatment Need (AC-IOTN) = 1 and Peer Assessment Rating Index (PAR Index) = 0 or 1] were photographed with a standardized pose while smiling, in the following settings (number of photographs = 960): without modifications, wearing eyeglasses, earrings, or lipstick. These pictures were taken with natural aligned dentition and with an individually manufactured crooked teeth mock-up (AC-IOTN = 8) to create the illusion of misaligned teeth. Images were assessed for attractiveness and perceived age, using AI, consisting of a face detector and deep convolutional neural networks trained on dedicated datasets for attractiveness and age prediction. Each image received an attractiveness score from 0 to 100 and one value for an age prediction. The scores were descriptively reviewed for each setting, and the facial modifications were tested statistically whether they affected the attractiveness score. The relationship between predicted age and attractiveness scores was examined with linear regression models. RESULTS: All modifications showed a significant effect (for all: P < 0.001) on facial attractiveness. In faces with misaligned teeth, wearing eyeglasses (-17.8%) and earrings (-3.2%) had an adverse effect on facial aesthetics. Tooth alignment (+6.9%) and wearing lipstick (+7.9%) increased attractiveness. There was no relevant effect of any assessed modifications or tooth alignment on perceived age (all: <1.5 years). Mean attractiveness score declined with predicted age, except when wearing glasses, in which case attractiveness was rated higher with increasing predicted age. CONCLUSIONS: Alignment of teeth improves facial attractiveness to a similar extent than wearing lipstick, but has no discernable effect on perceived age. Wearing glasses reduces attractiveness considerably, but this effect vanishes with age.

Periodontal disease progression in the second half of life and following a single episode of scaling and root planing: A clinical study in the Sri Lankan tea plantation cohort with documented clinical parameters for more than 40 years.

BACKGROUND: To evaluate periodontal disease progression (PDP) and potentially detectable effects of a single episode of scaling and root planing (se-SRP) in subjects lacking professional dental care and oral hygiene practices for >40 years. METHODS: In 2013, se-SRP was offered to all available subjects from the original cohort of 480 males initially established in 1970. From a total of 75 attending the previous examination in 2010 (baseline), 27 consented to receive the intervention while 18 declined and served as controls. Clinical data were recorded again in 2014 (follow-up) similarly to the previous surveys (1970 to 2010). RESULTS: Subjects' mean age in 2010 was 62.5 (± 3.6, test) and 61.9 (± 3.8, control) years. At follow-up, both groups presented with elevated tooth loss of 1.2 (from 15.5 ± 9.0, test) and 1.5 (from 17.9 ± 6.6, control) resulting in 1,392 (test) and 1,061 (control) sites available for further analysis. In both groups, clinical attachment level (CAL) loss and probing depths (PD) deteriorated. PD increase of 0.22 mm (± 1.70) in the test group was significantly higher compared with the control group (0.08 mm ± 1.30) (P <0.0001) demonstrating unaffected PDP. Computed estimates of further PDP revealed CAL and PD reductions in subjects aged ≥40 years. Specifically, the latter was positively correlated with tooth loss in subjects aged ≥40 years (P = 0.69, P = 0.0012) and ≥50 years (r = 0.62, P <0.0001). CONCLUSION: se-SRP in previously untreated periodontitis subjects aged ≥50 years may be ineffective in reducing PDP thus demanding advanced preventive measures, treatment in the first half of life, and sustained access to supportive care.

Factors influencing the removal torque of palatal implant used for orthodontic anchorage.

BACKGROUND: A non-invasive method has recently been introduced to remove osseo-integrated palatal implants by using the implantation ratchet which is designed to screw in or unscrew the implants. Although a proof of concept has been published, the torque involved to successfully explant have not been investigated so far. The aim of this study was to assess the removal torque required to explant osseo-integrated and orthodontically utilized palatal implants, and to identify potentially influencing variables. MATERIALS AND METHOD: Thirty-one consecutive patients (15 females, 16 males; mean age 24.1 ±7.4 years) with fully osseo-integrated and previously orthodontically loaded palatal implants (Orthosystem®: diameter 4.1mm/length 4.2mm/sandblasted with large grits (SLA) surface) were randomly assigned to either clockwise or counter-clockwise non-invasive explantation. The respective explantation tool with an electric torque control was placed on the abutment connection of the implant and secured by an occlusal screw. The primary outcome studied was maximal removal torque (MRT) needed to detach the implant from its socket which was recorded individually together with other potentially influencing secondary outcomes (gender, age, orthodontic loading time, use of local anaesthetics). Student's t-test was used to contrast MRT difference for the gender, type of suprastructure, use of local anaesthetics, and rotational direction. Spearman correlations was used to investigate associations between MRT and patient's age or duration loading time. RESULTS: Average MRT (148.6 ± 63.2N/cm) using ratchet as a non-invasive removal method of palatal implant was considered safe. The triangular head fractured of palatal implant at a torque level of 300.1 Ncm. Significantly higher explantation were recorded for male patients compared to female patients (182.0 ± 63.0 Ncm vs 112.8 ± 40.8 Ncm; P=0.001). On the other side, the mean removal torque for palatal removal in clockwise direction was non-significantly different (158.3 ± 58.6 Ncm) compared to counter-clockwise direction (139.4 ± 67.9 Ncm). Neither patient's age (p=0.324) nor loading time (p=0.214) were significantly correlated with removal torque values. CONCLUSIONS: Pertinent literature on this subject is practically non-existent, as orthodontics is presumably the only discipline where implant removal represents a treatment success. Mean MRT for successful palatal implant removal was 148.6±63.2Ncm, but a large spectrum was observed (minimum 31.5Ncm, maximum 272.8Ncm). This obvious heterogeneity underlines the importance to investigate possible influencing factors. The safe and simple non-invasive method for palatal implant removal necessitates moderate, but not high torque MRTs, independently of the torque direction. The necessary MRT seems clearly influenced by gender, but less so by patient's age or loading time.

[Prosthetic implants used as orthodontic anchor-age - Introducing a complete digital workflow for clinical use]. / Prothetische Implantate zur kieferorthopädischen Verankerung ­ Einführung eines komplett digitalen Behandlungsablaufs für den klinischen Einsatz.

The aim of this case report was to introduce the clinical use of a prosthetic soft tissue level implant and a completely digitized workflow for the production of an individualized suprastructure fixated on prosthetic implants for orthodontic anchorage rein­forcement. A prosthetic soft tissue level implant was placed in the palatal region for orthodontic anchorage reinforcement. Based on an intraoral optical scan taken after implant osseointegration, the orthodontic suprastructure was manufactured entirely by means of computer­aided design and manufacturing (CAD/CAM). The individualized suprastructure was subsequently loaded in direct manner. The prosthetic implant was then re­moved in a non­invasive manner, similar to palatal implants.The analysis included clinical and laboratory fabrication steps. The placement of prosthetic implant in the palatal region proved to be a painless, easy and fast procedure, and provided absolute anchorage during the entire intended orthodontic treatment. Its non­invasive removal did not cause any adverse patient reactions. The digitally constructed suprastructure did not require any chairside adaptation at delivery and was suc­cessfully used for the intended orthodontic treatment.The reported case presents the successful placement, loading and removal of a prosthetic soft tissue level implant for ortho­dontic anchorage use in the palatal region. The described digital and model­free workflow provides a feasible and streamlined treatment modality for the fabrication of individualized ortho­dontic suprastructures by means of CAD/CAM for the use as or­thodontic anchorage reinforcement. This proof of principle should be substantiated with further larger­scaled investigations.

Roughness and wettability of aligner materials.

OBJECTIVE: The characterisation of surface roughness and energy of contemporary thermoplastic materials used in manufacturing of orthodontic aligners. DESIGN: In vitro, laboratory study. MATERIALS AND METHODS: Four commercially available thermoplastic materials were selected (CA-medium/CAM, Essix-copopyester/COP, Duran/DUR and Erkodur/ERK). Five disks from each, as received, material were tested and subjected to: (1) reflected light microscopy; (2) optical profilometry for the estimation of Sa, Sz, Sq, Sdr, Sc, Sv surface roughness parameters (n = 5); and (3) contact angle measurements with a Zisman series of liquids for the estimation of critical surface tension (γC), total work of adhesion (WA), as well as the work of adhesion due to polar (WP) and dispersion (WD) components employing the Zisman method (n = 5/liquid). Thermoformed disks were prepared against a dental stone model and the roughness parameters were calculated again Statistical analysis was performed by one-way ANOVA/ Tukey multiple comparison test and t-test (a = 0.05). RESULTS: Microscopic and profilometric analyses revealed a smooth surface texture in the as-received materials, but a very rough texture after thermoforming, with insignificant differences within each state. Significant differences in the as-received state were found in the surface energy parameters; CAM showed the lowest γC and the highest WA, WP, WD, whereas ERK with the highest γC demonstrated lower WA. COP and DUR were ranked in an intermediate group regarding γC, with a statistically significant difference in WA between them, mainly attributed to the lower WP of the former. CONCLUSION: Given the differences in surface energy parameters and the lack of roughness differences within the as received or thermoformed groups, it may be concluded that variations in the plaque retaining capacity are anticipated, determined by γC, WA and the WP, WD components.

ATR-FTIR Analysis and One-Week Stress Relaxation of Four Orthodontic Aligner Materials.

The aim of this study was to estimate possible differences in the chemical composition and relaxation of orthodontic aligner materials. Four commercially available thermoplastic materials CAM (Scheu-Dental, Iserlohn, Germany), COP (Essix, Dentsply Raintree Essix Sarasota,FL, USA), DUR (Great Lakes Dental Technologies, Tonawanda, NY) and ERK (Erkodent Erich Kopp, Pfalzgrafenweiler Germany) were included in this study. Rectangular strips from each material were prepared according to the manufacturer's instructions and subjected to attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and stress relaxation characterization. The reduction in applied stress (RAS) after one week was estimated and statistically analyzed by one-way ANOVA at the 0.05 level of significance. All specimens were subjected to optical microscopy before and after stress relaxation testing under transmittance polarized illumination. ATR-FTIR microscopy revealed that all materials are made of polyethylene terephthalate glycol (PETG) while no significant differences were identified in RAS values among materials tested, which ranged from 6%-10% (p ≥ 0.05). All samples illustrated the developments of shear bands during relaxation testing according to optical microscopy findings. The tested materials illustrated similar chemical composition and relaxation behavior and thus no differences in their clinical efficacy are anticipated.

Improving headgear wear: why force level and direction of traction matter.

BACKGROUND: Empiric data on headgear wear are scarce. The aim was to examine a possible discrepancy between the duration of wearing and force application, and whether such a difference is influenced by force level or direction of traction. MATERIALS AND METHODS: In this retrospective analysis, 122 consecutive patients were included. All were treated with headgear (three subgroups: high-pull headgear [n = 60], cervical-pull headgear [n = 32], and high-pull headgear in combination with an activator [n = 30]) and were monitored for three successive months using an electronic module. The device recorded chronographically the measured force magnitude and temperature, allowing to differentiate between the duration of headgear wear (recorded body temperature) and actual force application (recorded force). RESULTS: For all subgroups, the average recorded force application was lower than wear time (mean inactivity during wear: 15.9 ± 22.8 minutes/night). The direction of traction significantly influenced the extent and length of wear time without force application (P < 0.001): patients with cervical-pull headgear were more prone to inactive wear time (27.7 minutes/night) than patients with high-pull headgear (13.7 minutes/night) or with headgear-activator (7.8 minutes/night). The observed inter-individual variability of inactive wear time was considerable (0-134 minutes/night). The mean applied force was highly significantly associated with inactive wear time (correlation coefficient: -0.575; P < 0.001), and force levels below 250 g seem particularly related to episodes of inactivity. CONCLUSIONS: There is a clear incongruity between the duration of headgear wear and the duration of force application. Inactive wear time is influenced by the direction of traction and force level applied. Clinicians should be aware of the likelihood of periods of inactive wear time and researchers should search for options to reduce or even eliminate these periods.

Natural history of periodontitis: Disease progression and tooth loss over 40 years.

OBJECTIVES: To assess long-term attachment and periodontitis-related tooth loss (PTL) in untreated periodontal disease over 40 years. MATERIAL AND METHODS: Data originated from the natural history of periodontitis study in Sri Lankan tea labourers first examined in 1970. In 2010, 75 subjects (15.6%) of the original cohort were re-examined. RESULTS: PTL over 40 years varied between 0 and 28 teeth (mean 13.1). Four subjects presented with no PTL, while 12 were edentulous. Logistic regression revealed attachment loss as a statistically significant covariate for PTL (p < .004). Markov chain analysis showed that smoking and calculus were associated with disease initiation and that calculus, plaque, and gingivitis were associated with loss of attachment and progression to advanced disease. Mean attachment loss <1.81 mm at the age of 30 yielded highest sensitivity and specificity (0.71) to allocate subjects into a cohort with a dentition of at least 20 teeth at 60 years of age. CONCLUSIONS: These results highlight the importance of treating early periodontitis along with smoking cessation, in those under 30 years of age. They further show that calculus removal, plaque control, and the control of gingivitis are essential in preventing disease progression, further loss of attachment and ultimately tooth loss.

The nasopalatine canal, a limiting factor for temporary anchorage devices: a cone beam computed tomography data study.

OBJECTIVES: There is only little knowledge on topographical predispositions of the nasopalatine canal as a limiting factor for insertion of mid-palatal temporary anchorage devices (TAD). The purpose of the study was to assess the course of the nasopalatine canal, the adjacent vertical bone quantity, and whether it might differ among vertical facial types, using pre-existing cone beam computed tomography (CBCT) scans. MATERIAL AND METHODS: Out of a consecutive sample collected from April 2008 to August 2012, only patient data depicting both upper and lower jaw completely were evaluated retrospectively. The linear measurements were taken on the respective midsagittal view perpendicular to the palate at the level of 1st molar/2nd premolar (5/6), 2nd premolar/1st premolar (4/5), and 1st premolar/canine (3/4). Screen-prints were used to measure the inclination of the nasopalatine canal in relation to the maxillary jaw base. Maxillary and mandibular divergence was assessed on rendered lateral cephalograms. RESULTS: Out of 3869 pre-existing consecutive CBCT scans, data from 398 patients met the inclusion criteria and could be extracted. The mean vertical bone was 4.09 mm at the 5/6 level, 5.22 mm at the 4/5 level, and 3.14 mm at the 3/4 level, respectively. A statistically significant negative correlation exists between jaw divergence and the canal angulation with regard to the maxillary base. A statistically significant negative correlation exists between the canal angulation and vertical bone measurements at the 4/5 and 3/4 levels. CONCLUSIONS: Vertical bone volume is sufficient at 4/5 level for TAD placement, and bares only a small risk for neuro-sensory impairment. Therefore, only in rare cases a CBCT is justified for palatal implant placement. The course of the nasopalatine canal is negatively correlated with the vertical skeletal facial pattern pointing to the fact that in hypodivergent patients a TAD might be placed in a more distal or paramedian region.

The Potential of Self-assembling Peptides for Enhancement of In Vitro Remineralisation of White Spot Lesions as Measured by Quantitative Laser Fluorescence.

PURPOSE: To test the remineralisation potential of a single application of self-assembling peptides or acidic fluoride solution using quantitative light-induced fluorescence (QLF) in vitro. MATERIALS AND METHODS: Bovine enamel disks were prepared, and white spot lesions were created on one half of the disk with an acidic buffer solution. After demineralisation, disks were allocated into three groups of 11 specimens each. Group A served as a control group and received no treatment. Group B had a single application of fluoride, and group C was treated once with self-assembling peptides. All disks were embedded in a plastic mold (diameter 15 mm, height 9 mm) with an a-silicone, and remineralisation was initiated using a pH-cycling protocol for five days. Four experimental regions on each disk were measured prior to the start of the study (T0), after demineralisation (T1) and after the remineralisation process (T2) using QLF. RESULTS: After demineralisation, all areas showed a distinct loss of fluorescence, with no statistically significant difference between the groups (ΔF from -69.3 to -10.2). After remineralisation, samples of group B (treated with fluoride) showed a statistically significant fluorescence increase (ΔF from T1 to T2 15.2 ± 7.3) indicating remineralisation, whereas the samples of control group A and group C (treated with self-assembling peptides) showed no significant changes in ΔF of 1.1 ± 1.9 and 2.5 ± 1.9, respectively. CONCLUSIONS: Application of self-assembling peptides on demineralised bovine enamel did not lead to increased fluorescence using QLF, indicating either lack of remineralisation or irregular crystals. Increased fluorescence using QLF indicated mineral gain following a single application of a highly concentrated fluoride.

Structural, morphological, compositional, and mechanical changes of palatal implants after use: a retrieval analysis.

PURPOSE: The aim of this study was to characterize the surface, elemental, and mechanical alterations of orthodontic palatal implants after intraoral aging. MATERIALS AND METHOD: Nineteen consecutively retrieved implants (RET) after orthodontic treatment and three unused implants used as control (CON) were included in this study. Both groups were characterized non-destructively by Stereomicroscopy, Optical Profilometry (Sa, Sq, Sz, Sc), and SEM/EDX analysis and then destructively after metallogaphic preparation employing instrumented indentation testing (HM, EIT, ηIT, and HV) and SEM/EDX at bone-implant interface. RESULTS: All retrieved implants showed a loss of gloss with the formation of bone-like formation on the majority of them. However, no differences in surface roughness parameters were identified between macroscopically intact and retrieved regions of implants. The elements precipitated on the surface were O, C, Ca, and P while traces of Na, K, Al, S, Cl, and Mg were also identified. The surface of control sample is characterized by small pits while only Ti and Al traces were identified by EDX analysis. The presence of all the aforementioned elements apart from Ti and Al on the retrieved implants' surface should be appended to the contact of implant with bone and biological fluids while Interfacial analysis revealed a well-formed bone-implant interface. However, no significant differences were found for all mechanical properties tested between RET and CON groups. CONCLUSIONS: The results of this study indicate that retrieved palatal implant surface has undergone morphological and elemental alterations probably associated with the osseointegration process during service. Insertion and functional loading did not affect the mechanical properties of implants tested.

Cleaning Efficacy of Manual Toothbrushes Around Brackets - A Pilot Randomised Control Trial.

PURPOSE: To test the cleaning efficacy of different manual toothbrushes in orthodontic patients in a single-blind randomised clinical trial. The brushes tested were selected based on previous in vitro tests. MATERIALS AND METHODS: Thirty-five regular orthodontic patients with a minimum of six bonded brackets on the maxillary anterior teeth were randomly assigned to three experimental groups: staged (2-level) (Candida Parodin, 12 patients) and V-shaped (Oral-B Ortho, 12 patients) toothbrush head designs were compared in a two-phase study to planar control brushes (Paro M 43, 11 patients). First, all participants were advised to brush their teeth twice daily for 2 min for 3 weeks. Prior to the start and at the end of the study, the gingival index was assessed to evaluate the level of oral hygiene. Afterwards, cleaning efficacy was assessed planimetrically by disclosing the respective teeth after two days of not performing any oral hygiene measures. RESULTS: Of the initial 35 participants, two did not attend after 3 weeks and had to be excluded. After 3 weeks, the control (5 out of 180 sites or -2.8% with GI ≥ 2) and staged groups (16 out of 216 sites or 7.5% with GI ≥ 2) showed minor improvement in the oral hygiene level. In contrast, the V-shaped group (29 out of 198 sites or 14.6 % with GI ≥ 2) showed a statistically significant improvement of the oral hygiene level. Planimetric evaluation, however, showed no superior cleaning efficacy of any of the tested head designs. CONCLUSIONS: The use of V-shaped and staged toothbrush head designs might be beneficial in patients with inadequate oral hygiene undergoing orthodontic treatment with a fixed appliance. Further large-scale investigations are, however, necessary to validate the presented results.