Tooth Separation Research Articles

Prosthetic Maintenance Assessment for Two Implant- Retained Overdentures Reinforced with PEKK Versus Co-Cr Framework: A Randomized Controlled Clinical Trial.

The primary challenge associated with implant overdentures lies in the occurrence of denture fractures around the attachments. Hence, it is recommended to enhance flexural strength through reinforcement frameworks. This study aimed to assess and compare the prosthetic maintenance of mandibular implant overdentures reinforced with Co-Cr and PEKK frameworks. Twenty-four participants with completely edentulous ridges were selected, and two implants were placed at the mandibular canine areas. After osseointegration period, ball attachments were installed. Participants were randomly assigned into two groups: Group I received a mandibular implant overdenture reinforced with a Co-Cr framework, while Group II received a mandibular implant overdenture reinforced with a PEKK framework. Prosthetic maintenance evaluations were conducted in both groups twelve months post-denture insertion. Categorical data were analyzed, and results were presented as frequency and percentage values. Group II exhibited a significantly higher percentage of cases with screw looseness, denture relining, and tooth separation compared to Group I. Although Group II cases showed a non-significant increase in the percentage of insert wear and retention loss. Within the limitations of this study, the findings suggest that Co-Cr, in contrast to PEKK frameworks, offers a more reliable reinforcement of the implant-retained overdentures.

EFFICIENCY OF TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION AND PIROXICAM TO ALLEVIATE PAIN DURING ORTHODONTIC TOOTH SEPARATION - A PROSPECTIVE STUDY

Objective: This study was conducted to assess the effectiveness of TENS in comparison with TENS-Placebo and prophylactic Piroxicam (20 mg) for pain control before orthodontic tooth separation by Elastomeric separators, Brasswire and Kesling separators. Study design: 108 patients seeking orthodontic treatment were categorically administered extraoral TENS, TENS-Placebo and Piroxicam (20 mg) using Elastomeric, Kesling and Brasswire separators prior to their orthodontic treatment. The subjects were instructed to rate their pain 2, 6, 12, 24 and 48 hours after the procedure on a Visual Analog Scale. Results: No statistically significant difference was found in the mean VAS scores when TENS group was compared with Piroxicam. However, significant differences were found between the mean VAS scores when placebo TENS group was compared to the aforementioned groups. Maximum pain was perceived at 24 hours with elastomeric and Kesling springs, but brasswire separators were most painful 6 hours after placement altogether. At all time stamps, pain felt was significantly less with brasswire separators than elastomeric separators and Kesling springs. Conclusion: TENS was found to be equally effective in reducing pain as Piroxicam. TENS could be thus stated as an effective pain management modality which is safe, comfortable and easy to use and also eliminates adverse drug effects of NSAIDs like GI irritation and reduced orthodontic tooth movement.

Effects of a new combination folkloric medicinal plant extract on bone formation in orthopedically expanded suture in rats

Objectives. The aim of this study was to evaluate histological effects of a new combination folkloric medicinal plant extract on bone healing in premaxillary suture expansion in rats. 
 Materials and methods. Thirty male Sprague–Dawley rats were used in this study. Rats were evenly divided into three groups (one control and two experimental groups) of ten each. The animals were subjected to premaxillary suture expansion by helix springs. The only expansion group is defined as the control group (Group A). The experimental groups are defined as OstokinPlus-10 (Group B) and OstokinPlus-20 (Group C). In the experimental groups, 10 and 20 ml/kg OstokinPlus herbals were applied systemically after the expansion by use of an orogastric tube during the time of study. The springs were placed and activated to deliver a 30 cN force. After 5 days, the springs were removed and replaced with short lengths of rectangular retaining wire. Tooth separation was maintained for 15 days. After a consolidation period of 15 days, the animals were euthanatized and the maxillary bone containing the midpalatal suture cartilage was surgically removed. The specimens were prepared for histomorphometric assessment of the regenerated bone. 
 Results. The midpalatal suture was successfully distracted following application of the activated helix spring. The distracted premaxillary suture was filled with new bone formation and unorganized fibrous tissues. Newly formed bone percentage and the bone area were found to have significant differences (p< 0.05). For investigated parameters, Group B and Group C revealed more positive results than Group A. 
 Conclusion: OstokinPlus herbal had positive effects on bone healing and formation during premaxillary suture expansion

Carrier-resolved real-field theory of multi-octave frequency combs

Optical frequency combs are pillars of precision spectroscopy, and their microresonator realization serves applications where miniaturization and large tooth separation are important. Microresonator combs cover an enormous range of time scales varying from the femtosecond periods of optical oscillations to milliseconds corresponding to the kilohertz linewidth of the comb teeth. Here, we develop and implement the carrier-resolved real-field model for multi-octave frequency combs, which allows for nearly ab initio capture of all the time scales involved. As an example, we consider a microresonator that has a mix of second- and third-order nonlinearities and uses periodic poling. By applying the real-field approach, we demonstrate how to surpass traditional limitations and model the spectral broadening and soliton mode-locking across three optical octaves.

Statistical elimination based approach to jaw and tooth separation on panoramic radiographs for dental human identification

Statistical elimination based approach to jaw and tooth separation on panoramic radiographs for dental human identification

Influence of anxiety and catastrophizing on pain perception in orthodontic treatment and its association with inflammatory cytokines.

Pain is common in orthodontic treatment, is subject to individual variation, and is associated with anxiety and stress, which can potentially become catastrophizing. The aim of the present study was to determine the variability of pain response after the insertion of orthodontic separators and to assess the association of pain levels with dental anxiety, catastrophizing, tooth sensitivity, and genetic expression of cytokines. To this end, 70 patients of both genders were divided into two equal groups according to the elastomeric separator used: G1 (Dentaurum) and G2 (Orthometric). Two separators were inserted in the mesial and distal sides of the lower right first molar. Participants were instructed to rate the level of pain at T0 (before insertion), T1 (just after insertion), and T2 (24 hours after insertion) on a visual analog scale. The gingival crevicular fluid was collected at T0 and T2. The levels of anxiety, catastrophizing, tooth sensitivity, and cytokine expression were also assessed. Statistical analysis was performed with the Fisher-Freeman-Halton, chi-squared, Spearman's correlation, and dependent and independent t tests (α=5%). Pain intensity was higher at T2 than at T1, in both groups (P<.05). An association was established (P<.05) between pain intensity at T1 and catastrophizing, and at T2 with anxiety and catastrophizing. Within-group differences in cytokine expression were found between T0 and T2. There was no correlation between cytokine expression and pain levels, anxiety, catastrophizing, and sensitivity at T2. Tooth separation produced variable pain levels, which were influenced by anxiety and catastrophizing, however, pain level was not correlated with increased cytokine expression.

Comparative analysis of Laser and LED phototherapies pain control after insertion of elastomeric separators in orthodontics patients: Clinical trial.

The aim of this study was to evaluate the effectiveness of pain modulation following Laser or LED phototherapies during the process of tooth separation. This was a longitudinal randomized controlled clinical trial in four observational times carried out in 60 patients (15 males, 45 females, average 24.1years old) who were randomly divided into three groups: G1 (LED, AsGaAl, λ850±10nm, 150mW, 17J/cm2, 57s per session), G2 (Laser, AsGaAl, λ780 nm, 70mW, 20.0J/cm2, 240s per session) and G3 (Non-irradiated Control). All patients were submitted to tooth separation using elastomeric separators. The pain level was measured by using a visual analogue scale (VAS) immediately after insertion (T1) of the elastic, at 48 (T2), 96 (T3) hours and 6days (T4). It was observed an increase of the pain on the Control group from T1 to T2, with statistical significance. Pain levels in the LED and Laser groups were always significantly lower (<0.001), except for T1. According with the results of the present study it may be concluded that, either LED or Laser phototherapies, were effective in reducing the pain level after dental separation process when compared to the control group.

Evaluation of fibre-reinforced composite splinting mobile the lower front teeth of patients who suffer from periodontitis

Aim: to evaluate the effectiveness of fibre-reinforced composite splints for lower front teeth immobilization in the scheme of complex therapy of severe periodontitis (III and IV stages) in short-term and long-term after treatment in persons with and without risk factors. Materials and methods. To reach the goal, a total of 58 patients with stage III and IV periodontitis were examined with identification of risk factors for the periodontal disease progression (smoking and diabetes). After a detailed periodontal examination, all patients were non-surgically treated for periodontitis, and mobile teeth were immobilized by fibre-reinforced composite splints. After splinting, mandatory supportive periodontal care was prescribed (every 3 months) with the dynamic monitoring of oral hygiene (PI), probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP) and the splint structure condition (cracks and fractures of the splint, violation of the marginal fit, a single tooth separation from the overall structure, chipping of the material and defects in the interdental spaces). The patients were dynamically examined before treatment, immediately after treatment (1 month) and at the long-term periods (12, 24, 36 months). Results. The splinting structure integrity was preserved in 67.24 % of patients for 3 years, and splinting defects were detected in 32.76 % of patients at different stages of the follow-up. Depending on the presence or absence of risk factors for periodontal disease, the splint structure integrity was preserved for 3 years in 18 patients (56.25 %) with associated risk factors and in 21 patients (80.77 %) without risk factors (P = 0.06). Conclusions. The use of fibre-reinforced composite splints for immobilization of lower front teeth in the scheme of complex therapy for periodontitis (III and IV stages) allowed to preserve mobile teeth and reduce values of the studied periodontal indices both immediately and in the long term after treatment in individuals with and without risk factors.

Theoretical analysis of nonlinear vibration characteristics of gear pair with shafts

The circumferential vibration of a gear pair is a parametric excitation caused by nonlinear tooth stiffness, which fluctuates with meshing. In addition, the vibration characteristics of the gear pair become complicated owing to the tooth profile error and backlash. It is considered that the circumferential vibration of the gear pair is affected by the torsional vibration of the shafts. It is important to understand quantitatively the vibration characteristics of the gear system considering the shafts. Therefore, the purpose of this research was to clarify the nonlinear vibration characteristics of a gear pair considering the influence of the shafts using theoretical methods. To achieve this objective, calculations were performed using equations of motion in which the circumferential vibration of the gear pair and the torsional vibration of the shafts were coupled. The nonlinear tooth stiffness was represented by a sine wave. The influence of tooth separation was considered by defining a nonlinear function using backlash and the tooth profile error. For the numerical calculations, both stable and unstable periodic solutions were obtained by using the shooting method. The effect of the shafts on the gear system vibration were clarified by comparing the results in the cases in which the shaft was not considered, one shaft was considered, and both shafts were considered.

Nonlinear dynamics of lumped-parameter planetary gears with general mesh phasing

This work derives analytical solutions for resonances and parametric instabilities of all rotational, translational, and planet modes, regardless of the degeneracy/multiplicity of the natural frequencies, for planetary gears with time-varying mesh stiffness excitation and tooth separation nonlinearity. Degenerate modes are the focus, but the results apply to all modes. For a degenerate mode resonance, use of mesh phasing results and modal properties from the literature reduces a problem with multiple, unknown, coupled modal amplitudes to one with a single unknown modal amplitude. This reduction allows derivation of a closed-form amplitude–frequency relation that is algebraically prohibitive otherwise. The analytical solution reveals important features such as the peak resonant amplitude and tooth contact loss occurrence. An instability suppression rule governs the occurrence or suppression of a potential parametric instability between any two natural frequencies, regardless of their multiplicity. Closed-form instability boundaries that bound the range of mesh frequencies where an unsuppressed parametric instability occurs are derived with and without damping. Counter-intuitively, damping can destabilize a parametric instability between two different natural frequencies by enlarging the instability bandwidth. The critical damping at which a parametric instability is eliminated is determined analytically. For parametric instabilities of a common type, the amplitude of nonlinear response with tooth separation is derived in closed-form. Numerical integration of a planetary gear model verifies all the analytical results. These numerical results also show rich nonlinear behaviors near parametric instabilities such as jump phenomena, period-doubling/halving, and quasi-periodic response.

Prosthetic and biological complications of implant-retained fixed versus removable telescopic overdentures

Background/aim Implant-supported prostheses proved to solve a lot of problems and difficulties associated with edentulism, yet some complications continued to appear after using the different modalities of implant-supported prostheses, so this study aimed to count and analyze the possible prosthetic and biological complications of implant-retained fixed versus removable overdentures. Patients and methods The study was conducted on 22 completely edentulous patients selected from the Outpatient Clinic of Prosthodontic Department, Faculty of Oral &amp; Dental Medicine, Badr University, Egypt. They were distributed randomly into two groups: group I received implant telescopic overdentures, group II received fixed detachable screw-retained implant-supported prostheses, and prosthetic and biological complications were evaluated after 1, 3, and 6 months. Results The present results indicated that Χ 2 test was performed for significance evaluation between both groups in biological and prosthetic complications. In biological complications, it revealed a significant difference in relining after 6 months between both groups as P value less than 0.05. While for prosthetic complications, there was a significant difference between both groups in tooth wear and tooth separation after 6 months as P value less than 0.05. Conclusion Regarding prosthetic complications, telescopic overdenture showed a higher incidence than hybrid fixed screw-retained screw looseness and screw fracture. Regarding biological complications, telescopic overdenture showed the same incidence as hybrid fixed screw-retained implant looseness with a higher incidence of denture relining and lower incidence in peri-implant mucositis.

A retrospective clinical study on the resin infiltration of proximal caries lesions: the operator\u2019s effect

PurposeThis retrospective university-based study investigated the effect of operators’ training and previous experience on the success of resin infiltration (RI) in arresting proximal non-cavitated caries lesions in primary and permanent teeth.MethodsInformation was collected regarding RI of proximal non-cavitated caries lesions in primary and permanent teeth with a follow-up period up to 32 months. Factors investigated were: operators’ clinical experience and training, patient’s age, tooth, arch, mouth-side, surface treated, tooth separation, and baseline lesion depth. Kaplan–Meier survival and Cox regression analysis with shared frailty were used (α = 5%).ResultsA total of 130 proximal surfaces treated on 115 teeth of 43 children (11 ± 4.4 years) were evaluated. Survival of RI was 46% up to 32 months. Lesions treated by non-trained dentists were more likely-to-present progression than those performed by non-trained dental students under supervision (HR 2.41, 95% CI: 1.00–5.80); conversely, no difference was found between non-trained dental students under supervision and trained dentists (HR 0.52, 95% CI: 0.16–1.70). Additionally, dentin lesions were 59% more-likely-to-present progression than enamel lesions (HR 0.41, 95% CI: 0.17–0.99).ConclusionThe operator’s experience and training could influence the success of RI on proximal non-cavitated caries lesions and it should be taken into consideration when choosing this treatment modality.

A new ctenochasmatid (Pterosauria, Pterodactyloidea) from the late Jurassic of Uruguay

A new ctenochasmatid pterosaur from the Tacuarembó Formation (Late Jurassic of Uruguay), Tacuadactylus luciae gen. et sp. nov. is described, based on a rostrum fragment with spatulated tip and dentary fragments. It closely resembles Gnathosaurus in the orientation of the teeth and the presence of interalveolar concavities. However, a unique combination of synapomorphies distinguishes it from other members of the Ctenochasmatidae. These include the presence of a spoon-shaped spatula not sharply demarcated from the post-spatula rostrum, teeth set in alveoli with raised alveolar borders and deep interalveolar concavities, teeth both anteriorly (i.e. procumbent) and laterally oriented, tooth density of 1.58–2 teeth/cm, tooth separation subequal to tooth size, absence of dorsal concavity, presence of a conspicuous system of vessels and foramina at least in the ventral part of the snout, teeth with veined sub millimetric texture of the enamel and unconspicuous carinae. In a phylogenetic analysis, the new taxon was retrieved as a gnathosaurine closely related to Gnathosaurus. The Tithonian-Berriasian biochron of the latter is coherent with the Late Jurassic age of the Batoví Member, as suggested by conchostracans and theropod teeth. This is one of the few South American Jurassic pterosaur taxa named so far and the oldest ctenochasmatid in this continent. As in Plataleorhynchus and Lonchodraco, Tacuadactylus luciae gen. et sp. nov. shows features that can be correlated with tactile foraging.

Jaw and Teeth Segmentation on the Panoramic X-Ray Images for Dental Human Identification.

Due to the damage to biometric properties in the event of natural disasters, like fire or earthquakes, it is very difficult to identify human remains. As teeth are more durable than other biometric properties, identifying information obtained from them is much more reliable. Therefore, in cases where alternative biometric properties cannot be obtained or used, information taken from teeth may be used to identify a person's remains. In recent years, many studies have shown how the identification process, previously performed manually by a forensic dental specialist, can be made faster and more reliable with the assistance of computers and technology. In these studies, the x-ray image is subdivided into meaningful parts, including jaws and teeth, and dental properties are extracted and matched. In order to extract the features accurately and ensure better matching, it is important to segment images properly. In this study, (i) lower and upper jaw and (ii) tooth separation was performed to segment panoramic dental x-ray images to assist in identifying human remains. To separate the jaws, a novel meta-heuristic optimization-based model is proposed. To separate teeth, a user-assisted, semi-automatic approach is presented. The proposed methods have been performed with a computer program. The results of the implementation of these methods of jaw and tooth separation in panoramic tooth images are encouraging.

Temporary Tooth Separation to Improve Assessment of Approximal Caries Lesions: A School-Based Study.

Radiographic lesion depth should not be used as the single determinant of the restorative threshold for clinically inaccessible approximal caries lesions. Temporary tooth separation is a feasible and effective diagnostic aid for assessment and appropriate management of approximal lesions. In the era of tooth-preserving dentistry, the decision to restore approximal caries lesions must be based on the accurate assessment of tooth cavitation, as the accumulation of oral biofilms in these areas encourages lesion progression. However, lesions radiographically into dentin remain the main threshold criterion for restoring approximal lesions even though most of these lesions may not be cavitated. A school-based clinical protocol for temporary tooth separation (TTS) was developed to improve visual-tactile assessment and management of clinically inaccessible approximal lesions. TTS data retrieved from electronic health records were used to correlate radiographic lesion depth and surface cavitation status with lesion location and the patient's caries risk and to evaluate the effectiveness of TTS as a diagnostic aid for approximal lesions. Of the 206 lesions assessed, 66.5% (n=137) were located in the maxillary arch, 56.6% (n=116) in distal surfaces, 61.3% (n=114) in premolars, and 21.5% (n=40) in molars. After tooth separation, 79.6% (n=164) of the lesions were diagnosed as noncavitated, including 90% (n=66) of the lesions radiographically at the inner half of enamel (E2) and 66% (n=49) of those at the outer-third of dentin (D1). Logistic regression analysis using E2 and D1 lesions showed no significant association between lesion depth or cavitation status with lesion location and caries risk. TTS is a feasible and effective diagnostic aid for the assessment and appropriate management of approximal caries lesions. There is a need to reevaluate the use of radiographic lesion depth as the single determinant of the restorative threshold for clinically inaccessible approximal lesions.

Restorative Direct Management of Cavitated Proximal Carious Lesions of Permanent Molars using Elastic Separators in Children and Adolescents

Purpose: The purpose of this study was to assess the longevity of direct amalgam and composite restorations placed on the mesial surface of permanent molars after separation with elastic separators. Design: One hundred and seventy seven (177) restorations placed on the mesial surfaces of first and second permanent molars in 140 patients aged 10-25 years-old (median age 12.2 years) were followed for a period of 1 to 12 years (median time 4.3 years). Eighty four (84) amalgam and 93 composite resin restorations were placed randomly on carious lesions that were detected by bite-wing x-rays at the dentino-enamel junction and verified as cavitated after tooth separation. Restorations were evaluated clinically according to the modified Ryge criteria. Flexible parametric proportional-hazards and proportional-odds models for censored survival data was used to analyze the data, with application to prognostic modelling and estimation of treatment effects at 95% CI. Results: Of the 177 restorations, 13 (7.2%) failed in a median time to failure of 8.8 years. There was no statistically significant difference on the cumulative median time to failures between amalgam and composite while statistically significant difference was found between patients that were using fluoride mouthrinse or not (p<0.048) and if there was bleeding detected at the interproximal area of the restoration or not (p<0.001). Conclusions: Restorative management of cavitated proximal carious surfaces of permanent teeth with amalgam or composite resin, using elastic separators, seems to be a very good and promising alternative technique in the context of the minimal invasive dentistry in children and adolescents.

Study on regional activities in the human brain caused by the low-level clenching and tooth separation: Investigation with functional magnetic resonance imaging

Study on regional activities in the human brain caused by the low-level clenching and tooth separation: Investigation with functional magnetic resonance imaging

Design and test of CF-1A self-propelled residual film recover machine

At present, although China has developed a biodegradable film, its impact is not ideal that the cost of degradation of the film is higher, and more difficult to promote widely. In order to solve the current problem of picking up the remains of the domestic films, the CF-1A self-propelled residual film recoverable machine is designed. The core components of equipment are the Swing-type residual film picking part and the membrane tooth separation mechanism. The test results have showed that residual film recoverable machine pick-up rate reaches at 82.5% to satisfy the farmers pick-up of the agricultural requirements on the residual film and provides a new idea for the design of the residual film picker.

Oral disorders related to acromegaly

Acromegaly is a rare disease caused due to hyper secretion of growth hormone. Most of the cases of acromegaly are caused by pituitary adenoma which can be microadenoma or macroadenomas. This condition has a tendency toward overgrowth of the mandible, maxillary widening, tooth separation and skeletal malocclusion which compromises the aesthetics of an individual. Hence dentists have a role in diagnosing this disorder. The aim of this paper is to present a case report of acromegaly.

Detection of Approximal Caries Lesions in Adults: A Cross-sectional Study.

Detection and management of posterior approximal caries lesions are still problematic. Inspection of approximal surfaces is challenging, and bitewing radiographs are used when direct vision is not possible. Unfortunately, there is no definite radiographic appearance to identify lesion cavitation with absolute certainty. Many lesions detected radiographically within the outer half of dentin are not cavitated, often resulting in unnecessary restorative treatment. Our study compared radiographic depth of approximal caries lesions with presence of cavitation in adults using visual inspection following temporary tooth separation (TTS). We conducted this observational descriptive cross-sectional study at two dental schools in two cities in Chile. Clinicians were unaware of radiographic depths of lesions and examined 147 participants (57.3% female and 42.7% male) following TTS. Using the common classification system that consists of E0 (no lesion), E1 (lesion within the outer half of enamel), E2 (lesion within the inner half of enamel), D1 (lesion within the outer third of dentin), D2 (lesion within the middle third of dentin), and D3 (lesion within the inner third of dentin), a trained dentist evaluated all the processed films. Cavitation was detected in only three sites (0.22%) within the E0 category, seven sites (3.41%) in E1, five sites (14.8%) in E2, four sites (14.8%) in D1, six sites (50%) in D2, and eight sites (61.5%) in D3. Considering that restorative treatment should be indicated strictly for cavitated lesions, our findings support indication for restorative treatment for D3 lesions and the rationale for TTS for D1-D2 caries lesions to allow direct visual inspection to determine whether there is surface cavitation.