Influence of attachment and bone loss on the mobility of incisors and canine teeth.

OBJECTIVE: The purpose of this clinical study was to evaluate the correlation between tooth mobility (TM), crown-to-root ratio (CRR) and clinical attachment loss (CAL) in periodontally-compromised participants. MATERIALS AND METHODS: While slowly biting on a load cell, the mobility of the upper incisors and canine teeth of 20 volunteers was measured using a photogrammetric measurement technique. An automated software program recorded the force-related three-dimensional TM at 3-N intervals. CAL was assessed clinically and CRR values were assessed radiographically. For each contralateral pair of teeth (central, lateral incisor, canine) and for each main level of force, the Pearson product-moment correlation coefficient between TM and CRR and between TM and CAL was computed. Correlations were considered statistically significant at p < 0.05. RESULTS: Statistically significant positive correlations were found between TM and CRR for incisors and canines for each main level of force, whereas canines had the lowest correlation. Statistically significant positive correlations were also found between TM and CAL for the central and lateral incisors at each main level of force. Canines showed no significant correlation between CAL and TM, regardless of force level. CONCLUSION: The loss of attachment and bone seem to have more influence on the mobility of incisors than canines.

Stock price movement prediction based on Stocktwits investor sentiment using FinBERT and ensemble SVM.

Investor sentiment plays a crucial role in the stock market, and in recent years, numerous studies have aimed to predict future stock prices by analyzing market sentiment obtained from social media or news. This study investigates the use of investor sentiment from social media, with a focus on Stocktwits, a social media platform for investors. However, using investor sentiment on Stocktwits to predict stock price movements may be challenging due to a lack of user-initiated sentiment data and the limitations of existing sentiment analyzers, which may inaccurately classify neutral comments. To overcome these challenges, this study proposes an alternative approach using FinBERT, a pre-trained language model specifically designed to analyze the sentiment of financial text. This study proposes an ensemble support vector machine for improving the accuracy of stock price movement predictions. Then, it predicts the future movement of SPDR S&P 500 Index Exchange Traded Funds using the rolling window approach to prevent look-ahead bias. Through comparing various techniques for generating sentiment, our results show that using the FinBERT model for sentiment analysis yields the best results, with an F1-score that is 4-5% higher than other techniques. Additionally, the proposed ensemble support vector machine improves the accuracy of stock price movement predictions when compared to the original support vector machine in a series of experiments.

Correlations between photogrammetric measurements of tooth mobility and the Periotest method.

OBJECTIVE: The purpose of the present study was to investigate whether or not the quantitative Periotest values of anterior teeth correlate with quantitative metric values of tooth mobility under vertical (VL) and horizontal load (HL) in periodontally healthy subjects. MATERIALS AND METHODS: Thirty-one subjects with good periodontal conditions were included and subjected to two different tooth mobility measurement techniques. Periotest values were measured at reproducible measurement points in the vertical (vPT) and horizontal (hPT) dimensions of upper central and lateral incisors and canine teeth. Using the optical measurement technique (photogrammetry), tooth mobility was measured under load in the horizontal (HL) and vertical loading directions (VL) at different load forces. Pearson's correlation coefficients were used to determine exploratory associations. RESULTS: The comparison between hPT and HL showed no correlations between the two measurements except for 'weak' and 'moderate' correlations for teeth 21 and 23. The analysis of correlations between vPT and VL data showed statistically significant correlations for both the left and right canine teeth that ranged from 'weak' to 'high'. Comparisons between hPT values and VL and between vPT and HL showed significant correlations at a few loading forces only. CONCLUSION: Quantitative Periotest values cannot be used to draw conclusions about the metric assessment of tooth mobility. For this purpose, the photogrammetric technique could be an additional tool for scientific questions.

An Osteotomy Tool That Preserves Bone Viability: Evaluation in Preclinical and Clinical Settings.

The main objectives of this work were to assess the efficiency, ease-of-use, and general performance of a novel osseoshaping tool based on first-user clinical experiences and to compare these observations with preclinical data generated in rodents using a miniaturized version of the instrument. All patients selected for the surgery presented challenging clinical conditions in terms of the quality and/or quantity of the available bone. The presented data were collected during the implant placement of 15 implants in 7 patients, and included implant recipient site (bone quality and quantity) and ridge evaluation, intra-operative handling of the novel instrument, and the evaluation of subsequent implant insertion. The instrument was easy to handle and was applied without any complications during the surgical procedure. Its use obviated the need for multiple drills and enabled adequate insertion torque in all cases. This biologically driven innovation in implant site preparation shows improvements in preserving vital anatomical and cellular structures as well as simplifying the surgical protocol with excellent ease-of-use and handling properties.

Surface characteristics of zirconia-based posterior restorations: clinical and scanning electron microscopic analysis.

AIM: The aim of this prospective clinical trial was to evaluate the performance of zirconia-based all-ceramic posterior fixed partial dentures (FPDs) after 4 years of clinical use. MATERIALS AND METHODS: Fifteen patients who needed 3- or 4-unit posterior FPDs were enrolled in the study. One manufacturer fabricated all restorations, following established clinical protocols and using computer-aided design/computer-aided manufacturing technology and one veneering material. Survival and success were evaluated clinically. Impressions were taken immediately after definitive cementation and after 48 months. Gold-coated epoxy replicas of the restorations were analyzed with scanning electron microscopy (SEM). Surface alterations were also evaluated clinically. RESULTS: After 48 months, the survival rate for the FPDs was 100%. Three restorations exhibited minor chipping, for a fracture rate of 20% after 4 years. Thirty (59%) of the 51 individual restoration units revealed clinically rough occlusal surfaces, a finding that was confirmed by SEM. CONCLUSION: The placement of 3- and 4-unit zirconia-based posterior FPDs can be considered a reliable treatment modality for medium-term clinical use. However, surface alterations of the veneering ceramics were observed after 4 years and are of notable clinical concern.

Parameters of implant stability measurements based on resonance frequency and damping capacity: a comparative finite element analysis.

PURPOSE: Contradictory results have been reported on the comparability of implant stability measurements performed with the Periotest and the Osstell Mentor devices. The purpose of the present finite element analysis was to simulate the influence of the parameters implant length, bone quality (cortical thickness and damping factor), bone loss, and quality of transducer fixation on resonance frequency analysis (RFA) and damping capacity measurements. MATERIALS AND METHODS: Three-dimensional finite element models of implants placed in human mandibular bone were designed for the simulation of Periotest (Periotest value; PTV) and RFA (implant stability quotient) measurements. Three values for each of the parameters implant length, damping capacity of cortical and trabecular bone, thickness of cortical bone, bone loss, and quality of transducer fixation were obtained. Measurements were simulated at four stages of osseointegration. RESULTS: For all parameters, an increase in implant stability was found with increasing levels of osseointegration. Implant stability was positively correlated with implant length and thickness of cortical bone, with slightly converging values at increased levels of osseointegration. Varying the damping factor of bone had no significant effect. Implant stability was negatively correlated with bone loss, with slightly converging values at increased levels of osseointegration. Linear changes in implant length and bone loss caused nonlinear effects in implant stability values. Stiffness of transducer fixation had an impact on RFA measurements when values below 10 GPa were applied. CONCLUSION: Although both measuring devices reacted similarly when different parameters of implant stability were changed, good correlation between Periotest values and implant stability quotients was observed only when measurement values of implants without bone loss were considered.

Bone loading caused by different types of misfits of implant-supported fixed dental prostheses: a three-dimensional finite element analysis based on experimental results.

PURPOSE: To show, by comparison of horizontal, vertical, and angular misfit in a three-dimensional finite element model, that clinical methods for the evaluation of implant framework fit cannot provide objective results. MATERIALS AND METHODS: Two three-dimensional finite element models were designed for the simulation of experimentally determined strain values of three-unit fixed dental prostheses supported by two implants. Horizontal, vertical, and angular misfits between implants and restorations were used to create predetermined strain levels. The magnitudes of misfit and resulting bone loading were recorded as von Mises equivalent stresses for the different types of misfit. RESULTS: A horizontal misfit of 36 µm and a vertical misfit of 79 µm had to be modeled to simulate the experimentally determined strain values. An angular misfit of 0.083 degree (equivalent to a gap of 3 µm on one aspect of the implant) resulted in comparable strain levels. Bone loading in the cortical area around both implants ranged from 50 to 90 MPa for horizontal and vertical misfit. In trabecular bone, loading of 2 to 5 MPa was found. For the angular misfit, bone loading up to 20 MPa in the cortical layer and 1 MPa in the cervical part of the trabecular bone occurred at the implant where the misfit had been introduced. Horizontal and vertical misfits led to comparable loading patterns around both supporting implants. Under angular misfit, bone loading mainly occurred around the implant where the misfit had been introduced. Almost no loading was observed in the circumference of the contralateral implant. CONCLUSIONS: Minimal angular misfits between implant abutments and restorations, which cannot be detected clinically, may lead to substantial bone loading.

Noncontact intraoral measurement of force-related tooth mobility.

The aim of this pilot study was to measure force-related tooth mobility. Vertical and horizontal anterior tooth mobility in 31 healthy periodontal subjects was measured by a noncontact optical measurement technique. The subjects continuously increased the force on each tooth by biting on a load cell. An automated software program recorded tooth displacement at 9-N intervals. Vertical and horizontal displacements were subsequently measured. The vector of tooth mobility in the buccal direction was calculated using the Pythagorean theorem. The average displacements over all subjects for each tooth were determined. Global differences were assessed with the Wilcoxon test. There were no significant differences between contralateral teeth overall load stages. There were no significant differences in tooth mobility between the central and lateral incisors except for in the horizontal direction. However, there were significant differences between central incisor and canine and lateral incisor and canine teeth.

Bond strength of different veneering ceramics to zirconia and their susceptibility to thermocycling.

PURPOSE: To evaluate the bond strength of recently developed feldspathic veneering ceramics to zirconium-oxide ceramic core material (Y-TZP). In addition, the effect of thermocycling on the bond strength was investigated. METHODS: 90 square Lava framework Y-TZP specimens were randomly assigned to three groups (n = 30) and veneered with one of the three zirconia veneering ceramics Cerabien ZR (CZR), GC Initial (GCI), or Lava Ceram (LC). 30 additional metal-ceramic specimens served as the control (VO). 15 specimens per group were stored in a saline solution for 3 days. To test the durability of the bond, 15 specimens per group were thermocycled for 10,000 cycles between 5 degrees to 60 degrees C with a 15-second dwell time. Shear strength was tested with an Instron universal testing system. A two-way ANOVA model and Tukey's HSD were applied for statistical analyses (alpha = 0.05). RESULTS: The different material combinations revealed significantly different shear bond strength values (CZR > GCI > LC > VO). All veneering ceramic/zirconia combinations showed significantly higher bond strength than the metal-ceramic control VO. Bond strength values were not affected by thermocycling, except for CZR, which had significantly higher bond strength after thermocycling. Microscopic evaluation of failure modes revealed 100% cohesive failures in the veneering ceramic for all specimens.

Prosthodontic treatment of a patient with bisphosphonate-induced osteonecrosis of the jaw using a removable dental prosthesis with a heat-polymerized resilient liner: a clinical report.

Bisphosphonate-induced osteonecrosis of the jaws (BONJ) is reported frequently in patients receiving oral or intravenous bisphosphonates. To minimize potential complications, dental treatment must be performed with care. There are invasive and noninvasive treatment options for patients with active BONJ or a history of this complication. This clinical report describes the prosthodontic treatment of a patient who developed BONJ after receiving intravenous bisphosphonates (pamidronate). Because of the recurrent incidence of BONJ, noninvasive prosthetic therapy with telescopic overdentures and a heat-polymerized resilient liner was provided. After 2 years, there were no biological or technical complications.

An evaluation of the Periotest method as a tool for monitoring tooth mobility in dental traumatology.

BACKGROUND/AIM: The Periotest method is a technique for the objective assessment of tooth mobility. The aims of this study were to determine normal Periotest values in the vertical and horizontal dimensions of periodontally healthy teeth in individuals aged 20-35 years and investigate the reliability of Periotest in terms of intra-series and inter-series reproducibility before and after applying a dental trauma splint in vivo. MATERIALS AND METHODS: Periotest values were measured in periodontally healthy dental students (n = 33; mean age 24.7 years) at reproducible measuring points in the vertical and horizontal dimensions, before and after splint insertion. Three readings were taken per series to observe the intra-series reproducibility; three series were measured to test inter-series reproducibility (Friedman-test; P

Zirconia abutments for single-tooth implants--rationale and clinical guidelines.

Clinical success of an endosseous implant to replace a single tooth is not only defined by its survival. Esthetic parameters have become integral aspects in defining success and failure. All-ceramic abutments have started to play a major role in achieving an esthetically successful result. The material itself, however, is not the exclusive determinant for esthetic success. It is the appropriate design and proper handling of the material and the abutment that enables the clinician to achieve esthetic outcomes that were not possible with traditional metal alloys. This article explores the rationale for using zirconia for prosthetic implant components, explains specific material properties, and discusses strategies and guidelines for the design and successful clinical implementation of CAD/CAM-fabricated zirconia implant abutments.

Prosthetic considerations for orthodontic implant site development in the adult patient.

Proper site development is a key factor for long-term clinical success of dental implants. Whereas surgical and restorative techniques have been refined to ensure predictable functional and esthetic outcome, individual clinical prerequisites do not always allow proper placement of implants when prosthetic and material properties are considered. Orthodontic tooth movement may be a viable and nonsurgical site development treatment option. With the introduction and advancements of minimal invasive and less visible orthodontic appliances, a growing number of adult patients are willing to obtain orthodontic treatment. The spectrum of modern appliances is broad and ranges from clear aligners to lingual brackets. Skeletal anchorage devices such as orthodontic mini-implants often eliminate unpopular external anchorage devices (ie, headgear) in adult patients, This article discusses the selection of an appropriate pretreatment approach by taking patient-specific criteria into account.

Biomechanical methods applied in dentistry: a comparative overview of photoelastic examinations, strain gauge measurements, finite element analysis and three-dimensional deformation analysis.

The aim of this article is to illustrate and discuss current methods applied in the analysis of biomechanical components in dental applications. For illustration purposes, the strain development of a non-passively fitting implant supported fixed restoration was evaluated using the four techniques: photoelastic examination, strain gauge measurements, finite element analysis, and three-dimensional deformation analysis. Photoelastic analysis only allowed for a raw estimation of the strains evoked by superstructure fixation. Quantitative results could be derived from both strain gauge measurements and three-dimensional deformation analysis which could then be used to simulate the loading situation around the supporting implants.

A Novel Osteotomy Preparation Technique to Preserve Implant Site Viability and Enhance Osteogenesis.

The preservation of bone viability at an osteotomy site is a critical variable for subsequent implant osseointegration. Recent biomechanical studies evaluating the consequences of site preparation led us to rethink the design of bone-cutting drills, especially those intended for implant site preparation. We present here a novel drill design that is designed to efficiently cut bone at a very low rotational velocity, obviating the need for irrigation as a coolant. The low-speed cutting produces little heat and, consequently, osteocyte viability is maintained. The lack of irrigation, coupled with the unique design of the cutting flutes, channels into the osteotomy autologous bone chips and osseous coagulum that have inherent osteogenic potential. Collectively, these features result in robust, new bone formation at rates significantly faster than those observed with conventional drilling protocols. These preclinical data have practical implications for the clinical preparation of osteotomies and alveolar bone reconstructive surgeries.

Comparing bar and double-crown attachments in implant-retained prosthetic reconstruction: a follow-up investigation.

OBJECTIVES: A removable implant-retained dental prosthesis in an edentulous mandible can use telescopic crowns or a bar superstructure as anchorage elements for an overdenture. The aim of this study was to compare the clinical results for bar-anchored and telescopic crown-retained overdentures in implant prosthetic treatment of the toothless lower jaw with two or more implants placed in the intraforaminal region. MATERIAL AND METHODS: A clinical and radiographical comparison was made of the telescope vs. the bar method for removable prosthetic rehabilitation treatments in patients with an edentulous mandible. For evaluation of the clinical data, the sulcus fluid flow rate, Periotest values, and the peri-implant bone loss were recorded. RESULTS: In the follow-up examinations, 19 implant losses were reported between insertion and review of 328 implants. The frequency distribution of the observed loss rates showed no treatment-specific trend. In the group with bar-treated implants, failure led to 'group loss' of the whole prosthetic superstructure. Failure of one of the double-crown-stabilized full dental prosthesis could usually be adapted so that the overdenture remained usable even without re-implantation. CONCLUSIONS: After comparing all the clinical parameters evaluated, no significant difference between the stabilization of full dentures via conus and telescopic crowns and bar-anchored dentures could be found. The choice of one particular method remains the decision of the professional treating the patient.

In vitro response of hFOB cells to pamidronate modified sodium silicate coated cellulose scaffolds.

The aim of the present study was to evaluate the suitability of cellulose-based scaffolds coated with pure sodium silicate gel and sodium silicate gels accumulated with different concentrations of the bisphosphonate pamidronate as scaffolds for attachment, proliferation and differentiation of human fetal osteoblasts (hFOB 1.19). Human osteoblasts were cultured in vitro for a period up to 14 days on different cellulose scaffolds. Unmodified and sodium silicate coated cellulose scaffolds were used as control. Two surface-coated modifications of cellulose were applied. The scaffolds were coated in a modified two-step dip coating process with pure sodium silicate gel and pamidronate enriched sodium silicate gel, respectively. In order to investigate the influence of the pamidronate, concentrations of 0.667 mg Na-pamidronate/ml sodium silicate solution, 0.333 mg Na-pamidronate/ml sodium silicate solution and 3.33 x 10(-3) mg Na-pamidronate/ml sodium silicate solution were used for the coating process. Cell proliferation, vitality and attachment were examined by means of cell counting, WST-1 test, fluorescence and scanning electron microscopy. The relative grade of differentiation of hFOB cells was examined by using quantitative real-time polymerase chain reaction (qRT-PCR) analysis for the gene expression of alkaline phosphatase and osteocalcin. Proliferation and differentiation of human osteoblasts was enhanced by the sodium silicate coatings accumulated with pamidronate compared to pure sodium silicate coatings. There was a reciprocal correlation of vitality with the concentration of pamidronate. The highest vitality was found on surfaces with the lowest pamidronate accumulation. Alkaline phosphatase, an early differentiation marker, was overexpressed after 7 days in cells on all pamidronate-containing surfaces (up to 350% compared to untreated cellulose). Osteocalcin, a late differentiation marker, was overexpressed after 14 days in cells on all coated surfaces (up to 300,000% compared to untreated cellulose). The results indicate that due to the modified coating procedure a homogeneous coating and thus, an enhancement of cell attachment and subsequent cellular functions can be achieved. Low concentrations of pamidronate seem to have a relevant effect on cell proliferation and vitality and, therefore, can be recommended for the improvement of the properties of a biomaterial.

The effect of provisional restoration type on micromovement of implants.

STATEMENT OF PROBLEM: The osseointegration or fibrous encapsulation of immediately loaded dental implants depends largely on the extent of implant micromovement. The impact of acrylic resin or metal-reinforced acrylic resin provisional restorations on this movement is currently unknown. PURPOSE: The purpose of this study was to isolate and measure the effect of provisional restoration type on the vertical displacement of adjacent implants under load at 2 locations. MATERIAL AND METHODS: Vertical loads ranging from 10-200 N were applied to polymethyl methacrylate resin (n=56) or metal-reinforced acrylic resin provisional restorations (n=56) supported by 4 implants inserted into homogenous artificial bone in a "u-shaped" alignment. Provisional restorations were first loaded in the anterior segment where the provisional restoration was supported by a mesial and distal implant, followed by loading on an extension 8 mm distal to the last implant. Vertical displacement of the 2 implants nearest the load application was measured and recorded using an optical image correlation technique based on photogrammetric principles. Data were subjected to a nonparametric multivariate analysis (generalized Wilcoxon test) and a Mann-Whitney test with a 2-tailed P value (alpha=.05). RESULTS: There was no significant difference in the vertical implant displacement of the 2 provisional restoration groups when they were loaded in the anterior segment. However, when loads were applied to the distal cantilever, metal reinforcement resulted in less vertical displacement of the next-to-last implant. The mean vertical displacement of the next-to-last implant when supporting an acrylic resin provisional restoration increased from 20 microm +/-3 microm (pooled loads of 10-50 N) to 130 microm +/-21 microm (pooled loads of 160-200 N), while the vertical displacement of the implant when retaining a metal-reinforced acrylic resin provisional restoration increased from 10 microm +/-2 microm to 69 microm +/-13 microm under the same loads (P

[Psychological and dental considerations in the prosthetic rehabilitation of children. Child prothesis--part I]. / Psychologische und zahnmedizinische Aspekte bei der prothetischen Versorgung von Kindern. Kinderprothesen--Teil I.

The fabrication of a prosthesis for a child requires an extensive diagnostic process together with a detailed medical and dental history. The treatment modalities for children and adults are different. By young patients attention must be paid in order to establish a feeling of trust and close cooperation between the dentist and the patient. The aim of the treatment with removable denture prosthesis is the re-establishment of aesthetic, phonetic and function while assuring at the same time a high standard of oral hygiene and periodontal maintenance. The continuous jaw growth and the dentition changes of a child must be closely monitored. Therefore, frequent (3-6 months recall intervals) follow-up examinations and denture adjustments are needed.

[Technical treatment considerations in making prostheses for children. Child prostheses--Part 2]. / Behandlungstechnische Aspekte bei der Anfertigung von Kinderprothesen. Kinderprothesen--Teil II.

The rehabilitation of a child's dentition with a removable prosthesis is more complex and time consuming, when comparing it to the one of adults. Prerequisite for a successful treatment is a careful consideration of age-related, technical, functional and psychological aspects. The aesthetic and functional replacement of the missing teeth using a removable prosthesis results in an increased self-esteem for the young patients. This case report describes the management of a young child as well as the treatment planning and the prosthetic rehabilitation process.