Resorption Level Research Articles

Cervical vertebrae for early bone loss evaluation in osteoporosis mouse models.

Osteoporosis (OP), a systemic skeletal disease common in aged population, is an important public health problem worldwide. Animal models are important tools for understanding OP. In ovariectomy (OVX) or orchiectomy (ORX) OP models, lumbar vertebrae are often used for evaluating of the OP progression. However, unlike the bipeds, the lumbar vertebrae are not weight loading bones in quadruped animal, but the head-bearing cervical vertebrae take much higher stress. So, we compared the murine cervical vertebrae with lumbar vertebrae for OP assessment. OVX and ORX mouse models were established on C57BL/6J mice. Serum estradiol, testosterone and bone related biomarkers were verified. Bone quantity and quality were determined using micro computed tomography (micro-CT) analysis. Hard tissue sections were prepared, stained for histomorphological analyzing, and micro-indentation measured for bone mechanical property evaluation. In OVX and ORX mice, serum estradiol or testosterone levels reduced, bone resorption level and related biomarkers elevated, indicated the successful generation of the OP models. In the early stage, the trabecular bone mineral density (BMD) of cervical vertebrae was already reduced 16.1% (OVX) and 21.7% (ORX) one-month post-gonadectomy, respectively; while this decline in the fifth lumbar vertebra were only 5% and 7.4%, respectively. Six months post-gonadectomy, the reduction of BMD in cervical vertebrae and the fifth lumbar vertebra were 31.2% & 36.1% and 28.5% & 30.7% respectively. In biomechanical aspects, cervical spines showed worse Vickers hardness (HV) and elastic modulus than lumbar spine in six-month OVX and ORX mice. We provide a new OP early-stage evaluation mouse model based on the cervical spine. Through the radiographic, biological and biomechanical assessments, the mouse cervical spine is more suitable for bone remodeling evaluation in OP models than the conventional lumbar vertebrae, especially for early-stage OP study.

Reduced bone formation and increased bone resorption drive bone loss in Eimeria infected broilers

Coccidiosis is an economically significant disease in the global poultry industry, but little is known about the mechanisms of bone defects caused by coccidiosis; thus, the study focused on effects of coccidiosis on the bone homeostasis of young broiler chickens. A total of 480 male Cobb500 broilers were randomly allocated into four treatment groups, including an uninfected control consuming diet ad libitum, two infected groups were orally gavaged with two different concentrations of sporulated Eimeria oocysts, and an uninfected pair-fed group fed the same amount of feed as the high Eimeria-infected group consumed. Growth performance and feed intake were recorded, and samples were collected on 6 days post infection. Results indicated that coccidiosis increased systemic oxidative status and elevated immune response in bone marrow, suppressing bone growth rate (P < 0.05) and increasing bone resorption (P < 0.05) which led to lower bone mineral density (P < 0.05) and mineral content (P < 0.05) under Eimeria infection. With the same amount of feed intake, the uninfected pair-fed group showed a distinguished bone formation rate and bone resorption level compared with the Eimeria infected groups. In conclusion, inflammatory immune response and oxidative stress in broilers after Eimeria infection were closely associated with altered bone homeostasis, highlighting the role of inflammation and oxidative stress in broiler bone homeostasis during coccidiosis.

An evaluation of the impact of En-masse retraction on root resorption and vertical alveolar bone level using cone-beam computed tomography

An evaluation of the impact of En-masse retraction on root resorption and vertical alveolar bone level using cone-beam computed tomography

The efficacy of hydrogel containing zinc oxide-loaded and minocycline serum albumin nanopartical in the treatment of peri-implantitis.

We conducted this animal study to assess the efficacy of the novel hydrogel containing zinc oxide-loaded and minocycline serum albumin nanoparticals (Mino-ZnO@Alb NPs) on peri-implantitis in an experimental mouse model. Mino-ZnO@Alb NPs was prepared as previously reported. The peri-implantitis model was successfully established in rats, and the rats were divided into three groups randomly: Mino-ZnO@Alb NPs (Mino-ZnO) group, minocycline group, and untreated group. Four weeks later, clinical and radiographic assessments were performed to evaluate soft tissue inflammation and bone resorption level. Histologic analysis was performed to estimate the amount of remaining supporting bone tissue (SBT) around implants. ELISA tests were used to determine the concentration of inflammation factor interleukin-1-beta (IL-1β) and anti-inflammation factor tumor necrosis factor-alpha (TNF-α) around implants. After one month, the Mino-ZnO group showed better results than the other two groups in regards to the results of bleeding on probing, probing pocket depth, bleeding index and gingival index. X-ray showed that SBT at mesial and distal sites around implants in the other two groups was significantly lower compared with that of Mino-ZnO group. The quantity of osteoclasts in peri-implant tissues of the Mino-ZnO group was less than that in the minocycline and untreated groups. IL-1β in the Mino-ZnO group was lower than that in the other two groups. TNF-α level was the opposite. Mino-ZnO@Alb NPs can effectively treat peri-implantitis and promote soft tissue healing, and may act as a promising product.

Biomedical response of femurs in male Wistar rat in chronic hypergravity environments

Bone is sensitive to mechanical stimulation and plays a loading-bearing role in the human body. However, regulation of bone biomechanical properties in chronic hypergravity environments is still unclear. In this study, male Wistar rats exposed to chronic hypergravity environments (4×g, 8×g, 10×g, and 20×g) for 4 weeks were set as the hypergravity groups, and rats exposed to the normal gravity as the control group. Morphology parameters and bone remodeling factors were obtained by means of micro-CT, Western blot, and q-PCR. Mechanical properties of femurs were measured utilizing three points bending test and creep test and were fitted into a viscoelastic-viscoplastic constitutive equation. The results indicate osteoporosis occurred in femurs of hypergravity groups. Accordingly, the protein and gene expressions of bone remodeling factors (OPG, RANKL, runx2) in hypergravity groups were significantly different from that in the control group, demonstrating that bone formation level increased and bone resorption level decreased. Meanwhile, mechanical properties of femurs in hypergravity groups showed that Young's modulus of femurs in the 20×g group was significantly higher than that in the control group. The viscoelastic-viscoplastic properties of bone tissue were changed in hypergravity environments. Among them, the 8×g group was closest to the control group in morphology and mechanical properties. To sum up, the biomechanical response regulation of rat femur under 4-20×g chronic hypergravity environments was presented. Hypergravity environments could lead to osteoporosis. The balance between bone formation and bone resorption would be disrupted in hypergravity groups due to bone adaptation. 20×g environment has a significant effect on elastic modulus on femurs. Due to the difference in biomechanical response of femurs, the viscoelastic-viscoplastic characteristics of femurs have a nonlinear relationship with hypergravity values. Bone tissue was least affected by 8×g hypergravity in morphology and mechanical properties.

Assessment of modified reconstructive technique effectiveness to treat chronic peri-implantitis

Relevance. The article presents positive clinical outcomes of using a modified reconstructive technique around 20 implants in 14 patients. Its effectiveness was statistically assessed using linear regression analysis. Material and methods. Clinical data of 20 patients treated from 2014 to 2021 for chronic peri-implantitis around 27 teeth provided the basis for the study. The patients formed two groups: control (6 patients (7implants)) and study (14 patients (20 implants)) groups. A staged treatment approach was applied to all patients and included anti-inflammatory, reconstructive and maintenance stages. In the control group of patients, we finished the treatment at the first stage, as stable clinical remission was achieved after the surgery. In the study group, there were two stages: anti-inflammatory treatment and reconstructive treatment with a modified reconstructive technique. Before and after treatment, we isolated biomarkers specific to surgery results, represented by independent and dependent variables. The received data were statistically evaluated using linear regression analysis (Gretl) to assess the effectiveness of a new surgical technique by studying numerical relationships between two groups of variables. Results . The modified reconstructive technique as a part of a staged approach increased the effectiveness of chronic peri-implantitis treatment up to 74%. The statistical analysis demonstrated a significant influence of the baseline bone resorption level (vr1), defect shape (fd) and inflammation level (s) on the formation of new tissue attachment around the implants (gz2). The intensity of surgically induced stress response (str) directly correlated with surgery injury (hm) and baseline inflammation level (s). Surgical wound healing (pk), most closely related to implant survival (del), did not have a meaningful relationship with surgery-induced stress response intensity (str), which indicates the crucial role of the microbial fac tor in surgical wound healing around implants. Conclusion . A new modified surgical technique increases the effectiveness of chronic peri-implantitis treatment to 74% due to the stability of a pedicled vascularized submucoperiosteal flap in the inflammation area. The study did not detect the direct impact of the periosteal reparative-regenerative potential on the radiological bone level restoration. However, it demonstrated clinically significant positive results. Inability to fully control microbial biofilm on the implant surface remains the main problem of chronic peri-implantitis treatment.

Effect of Posterior Residual Ridge Resorption and Relining for Mandibular Implant Overdentures on Bending Strain Around Implants.

To examine the influence of posterior residual ridge resorption (PRRR) and relining on bending strain around implants under an overdenture. Maxillary and mandibular edentulous models were made and covered with white silicone. Four strain gauges were placed on four sides of each implant. Two tissue-level implants were placed bilaterally in the part between the lateral incisors and canines of the mandible. A maxillary conventional denture and a mandibular overdenture were fabricated to fit the models. Three levels of bone resorption around the implant were created: 0, 0.8, and 1.5 mm. The surface of the residual ridge was uniformly removed from the area near the distal side of the implant to the retromolar section, and three levels of PRRR were created (0, 1, and 1.5 mm). After the measurement, the experimental denture of the PRRR of 1 mm and 1.5 mm were relined. Locator attachments were used. A 98-N occlusal force was applied, and bending strains around the implant were measured. The Kruskal-Wallis test and Bonferroni correction were employed to analyze the data. Without relining, at each bone resorption level around the implant, the bending strain was smallest with PRRR of 0 mm and largest with PRRR of 1.5 mm. The bending strain after relining was smaller than the bending strain with ridge resorption. Bending strains after relining were smaller than bending strains with no ridge resorption, but there was no significant difference in bending strain between these three groups. As PRRR increased, the bending strain increased without relining. As bone resorption around the implant progressed, PRRR enhanced the increase in the peri-implant bending strain. Bending strain was reduced when relining was performed.

The changes in bone turnover markers of female systemic lupus erythematousus patients without glucocorticoid.

SLE is a chronic autoimmune disease, which can affect the level of bone metabolism and increase the risk of osteoporosis and fracture. The purpose of this research is to study the effect of SLE on bone turnover markers without the influence of glucocorticoids. A total of 865 female subjects were recruited from Zhejiang Provincial People's Hospital and the First Hospital of Jiaxing, including 391 SLE patients without the influence of glucocorticoids and 474 non-SLE people. We detected Bone turnover markers including amino-terminal propeptide of type 1 procollagen (P1NP), C-terminal turnover of β - I collagen (β-CTX), N-terminal midfragment of osteocalcin (NMID) and 25(OH)D, and analyzed the difference in Bone turnover markers between the SLE group and the control group, as well as the influence of age and season on bone metabolism in female SLE patients. In the SLE group, the average age was 43.93±13.95 years old. In the control group, the average age was 44.84±11.42 years old. There was no difference between the two groups (t = 1.03, P = 0.30). P1NP, NMID and 25(OH)D in the SLE group were significantly lower than those in the control group (Z = 8.44, p < 0.001; Z = 14.41, p < 0.001; Z = 2.19, p = 0.029), and β-CTX in the SLE group was significantly higher than that in the control group (Z = 2.61, p = 0.009). In addition, the levers of β-CTX, NMID, P1NP and 25(OH)D in older SLE female patients were statistically significantly higher than those in younger (ρ = 0.104, p = 0.041; ρ = 0.223, p < 0.001; ρ = 0.105, p = 0.038; ρ = 0.289, p < 0.001). Moreover, β-CTX reached a high value in summer and PINP reached a low value in winter. The bone formation markers of female SLE patients without glucocorticoid were lower than those of normal people and the bone resorption marker was higher than that of normal people. The 25 (OH) D of female SLE patients without glucocorticoid was lower than that of normal people. The risk of osteoporosis and fracture may be higher in elderly women with SLE. The bone resorption level of female SLE patients is high in summer and the bone formation level is low in winter.

Evaluation of apical root resorption occurrence in orthodontic patients treated with fixed braces depending on selected clinical parameters

Abstract An aim of the work was analysis of the possible connections between the selected clinical parameters and external apical root resorption (EARR) in patients after orthodontic treatment. The study comprised 101 persons, who underwent complex orthodontic treatment with the use of fixed braces (straight-arch technique). The teeth chosen for measurement of resorption level were central and lateral incisors of mandible and maxilla, as well as maxillary first molars, which are the most susceptible to root resorption. The roots were measured on the basis of the dental radiographs taken before and at the end of treatment. The measurements were made on digital radiographs with the use of diagnostic software (Planmeca Romexis® Viewer), which allows the image filters ensure the highest precision when localizing roots end points. Proportional measurements of the chosen teeth were made with the use of Linge’s method and Linge’s method modified by Brezniak et al. For further analysis, the persons taking part in the study were divided into two groups depending on the presence of postorthodontic EARR or its lack, resulting from radiographic measurements: a control group comprising 61 patients without EARR (with 0.90 ≤ rRCR ≤ 1.00) and a study group including 40 patients with EARR (rRCR &lt; 0.90). In statistical analysis there was used verification of statistical hypotheses based on the following tests: Pearson’s chi-squared test, Student’s t-test, Mann-Whitney U test. On the basis of the made analyses and achieved results, it was found out that age, sex, type of skeletal malocclusion, increased overjet and overbite do not constitute risk factors for EARR occurrence. Excessive proclination of central and lateral incisors of mandible and maxilla predisposes to shortening the roots of these teeth during orthodontic treatment with fixed braces (p &lt; 0.01).

The variability of electric pulp response thresholds in primary molars: a clinical study

The variability of the EPT response threshold is the most important part of accurate diagnosis of pulp status of caries-affected resorbing primary teeth. This study evaluated the mean EPT threshold values and appropriate electrode placement sites for primary molar teeth based on their physiological root resorption levels. This study was conducted with 100 primary second molars in 100 children ages 3-12 (mean age: 7.88years). Teeth were divided into 2 groups according to physiological root resorption levels. EPT response thresholds were recorded at the mesiobuccal cusp, occlusal third, middle third and cervical third of the crown. Data were analyzed according to resorption level using one-way analysis of variance and Duncan tests, with the level of significance set at 0.05. Mean threshold values at all placement sites were higher in the group with the higher level of physiological root resorption. In terms of placement, the lowest mean EPT threshold values were obtained at the mesiobuccal cusp regardless of resorption level. According to the study results, higher resorption levels were associated with higher physiologocial threshold values for EPT of primary second molars, with the mesiobuccal site identified as the most appropriate electrode placement site, regardless of resorption level.

Flowable Urethane Dimethacrylate-Based Filler for Root Canal Obturation in Primary Molars: A Pilot SEM and microCT Assessment.

Pulpectomy in deciduous teeth involves endodontic access opening, root canal debridement and obturation with an appropriate filling material. EndoREZ (ER) is the urethane dimethacrylate-based filler, which can be used for root canal obturation in permanent and primary teeth. This observation aimed to evaluate the behavior of the ER as a filler in root canals of two primary molars after the physiological resorption process using the scanning electron microscopy (SEM) and micro-computed tomography (µCT) in second lower molars after their natural exfoliation. The SEM analysis revealed a non-uniform, porous and lacunary structure of ER, visually similar to the resorbed surface of the dentine. The µCT observations demonstrated the differences in the resorption level of the root and material surfaces. The preliminary observations suggest that ER is resorbed faster than root tissues and can therefore be a suitable material for the root canal filling in primary teeth. However, more investigations are needed to support these preliminary findings.

Effect of the Features of Mandibular Implant Overdenture Attachments on the Bending Strain Around Implants

To examine the effect of the attachment features (abutment height, retention, and freedom of rotation) of implant overdentures on the bending strain around implants under an overdenture. Mandibular and maxillary edentulous models were fabricated and covered with silicone rubber. Strain gauges were attached to the four sides of each implant. Two implants (tissue-level implant, 4.1-mm diameter, 10-mm length) were placed bilaterally in the area between the mandibular canines and lateral incisors. A maxillary conventional denture and a mandibular overdenture were made to fit the edentulous models. Three levels of peri-implant bone resorption were created sequentially: no bone resorption, 0.8 mm, and 1.5 mm. Three kinds of attachments (magnetic, stud, and ball attachments) were used. Bending strains generated from a 98-N occlusal load through the maxillary denture were measured using a sensor interface, and the data were analyzed using the Kruskal-Wallis and Bonferroni tests. Multiple regression analysis was used to find the relationship between independent variables (peri-implant bone resorption level, abutment height, retention, and freedom of rotation) and the dependent variable (bending strain). For all attachment types, the bending strains were smallest with no bone resorption and largest with 1.5-mm bone resorption (P < .05). Multiple regression analysis showed that abutment height had the greatest impact on the reduction of bending strain (beta = .413), followed by freedom of rotation (beta = -.349), and retention (beta = .107). Low abutment height, large freedom of rotation, and low retention can minimize bending strain around implants.

Socket Preservation During Preimplantation Period: Effi cacy of Osteoplastic Material Application Using Cone Beam Computed Tomography

Aim. To analyse the effi ciency of osteoplastic material application in order to reduce the resorption level after tooth extraction in the preimplantation period according to the data of cone beam computed tomography.Materials and methods. The study involved 80 patients who were divided into 4 equal groups depending on the preservation material used. The fi rst group was treated with Cerabone (Botiss, Germany) xenomaterial based on natural bovine bone. Plasma enriched with PRGF growth factors obtained by the BTI Endoret (Spain) technology was used for the patients of the second group. The third group consisted of patients who underwent a socket preservation of the extracted tooth with a powdered autologous dentin matrix (ADM) obtained from their own tooth. In the fourth group, bone-plastic material based on hydroxyapatite with Collapan-L lincomycin hydrochloride (Intermedapatit, Russia) was used to prevent socket resorption. All patients had a cone beam computed tomography of the maxillofacial region before the extraction and 3 months after the preservation in order to evaluate the level of bone resorption. After the installation of dental implants, a comparative assessment of the bone resorption level in the vertical and horizontal directions before tooth extraction and in the preimplantation period was carried out.Results. The smallest level of vertical bone resorption after socket preservation was observed in group 1 (Cerabone) and group 3 (ADM). The median value of the socket resorption level in group 1 was 0.7 mm (8.54 %) in the vertical direction and 0.5 mm (9.45 %) in horizontal measurement as compared to the level of bone tissue before tooth extraction. Similar indicators were observed in the group using an autologous dentin matrix. The vertical decrease in the socket bone tissue was 0.61 mm (7.75 %), horizontal — 0.51 mm (6.2 %). The level of bone resorption was signifi cantly higher using two other materials.Conclusions. The use of three-dimensional radiation research methods allows a comprehensive assessment of the bone tissue volume to be carried out, which in turn determines the choice of the dental implant size, the need for further bone-plastic surgery to increase the width/height of the alveolar ridge. The use of cone beam computed tomography showed that the most optimal results can be obtained by introducing Cerabone material into the socket of the extracted tooth, as well as using the innovative method of preservation with the patient’s own powdered tooth (ADM).

A bone resorption marker as predictor of rate of change in femoral neck size and strength during the menopause transition.

Composite indices of the femoral neck's ability to withstand compressive (compression strength index, CSI) and impact (impact strength index, ISI) forces integrate DXA-derived femoral neck width (FNW), bone mineral density (BMD), and body size. During the menopause transition (MT), FNW increases, and CSI and ISI decrease. This proof-of-concept study assessed whether a bone resorption marker, measured early in the MT, is associated with rates of change in FNW, CSI and ISI during the MT. We used previously collected bone resorption marker (urine collagen type I N-telopeptide [U-NTX]) and femoral neck strength data from 696 participants from the Study of Women's Health Across the Nation (SWAN), a longitudinal study of the MT in a multi-ethnic cohort of community-dwelling women. Adjusted for MT stage (pre- vs. early perimenopause), age, body mass index (BMI), bone resorption marker collection time, and study site in multivariable linear regression, bone resorption in pre- and early perimenopause was not associated with transmenopausal decline rate in femoral neck BMD. However, each standard deviation (SD) increase in bone resorption level was associated with 0.2% per year slower increase in FNW (p = 0.03), and 0.3% per year faster declines in CSI (p = 0.02) and ISI (p = 0.01). When restricted to women in early perimenopause, the associations of bone resorption with change in FNW, CSI, and ISI were similar to those in the full sample. Measuring a bone resorption marker in pre- and early perimenopause may identify women who will experience the greatest loss in bone strength during the MT.

What are the best materials to use for the first arch wire in orthodontic treatment?

Data sources Six electronic databases/registries including Medline, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Oral Health's Trials Register, Embase, World Health Organization International Clinical Trials Registry Platform and The US National Institutes of Health Trials Registry (ClinicalTrials.gov) were searched up to October 2017. No restrictions of language or publication date were set.Study selection Only randomised controlled trials (RCTs) assessing the efficiency of initial arch wires to align teeth with fixed orthodontic braces in either or both upper and lower arches.Data extraction and synthesis Two reviewers abstracted data independently. Risk of bias was assessed using the Cochrane Collaboration Risk of Bias tool. Rate of alignment was considered the main outcome. Root resorption and pain level were considered adverse effects. Meta-analysis was performed when possible. Results Twelve RCTs involving 799 participants were included. Three studies were judged at high RoB, six were unclear and three were at low RoB. There was insufficient evidence to determine if there is a difference in the alignment rate between Multistrand stainless steel (MSS) and superelastic nickel-titanium (SNT) arch wires (mean difference (MD) -7.5 mm per month, 95% confidence interval (CI) -26.27 to 11.27; one study), between MSS and thermoplastic NiTi (TNT) arch wires, between conventional Niti (CNT) and TNT arch wires, between CNT and TNT arch wires and between SNT and TNT arch wires. In regards to pain level only two comparisons were assessed (MSS vs. SNT and SNT vs. TNT). The first one did not show meaningful differences while in the second insufficient evidence was identified. Conclusions In general terms there is insufficient evidence that any particular material is clinically superior to any other in regards to alignment rate, pain or root resorption.

Influence of the Presence of Alveolar Mucosa at Implants: A Histological Study in Humans.

To evaluate the influence of the presence or absence of keratinized mucosa on hard and soft tissues around implants. Sixteen volunteers with edentulous regions in the distal aspect of the mandible participated in the study. In each patient, 2 solid titanium screw-shaped devices, 3.5 mm in diameter and 5 mm long, were installed. The incision of the mucosa was performed in such a way to allow that, after the suture of the flaps, only the alveolar mucosa surround the test sites and the keratinized mucosa surround the control implants. After 3 months of healing, biopsies were retrieved and ground sections were prepared for histological analysis. Eighteen biopsies from 9 patients were collected for analysis. Both buccal bone resorption and most coronal level of osseointegration were higher at the test sites compared with the control sites, the difference between the 2 sites being 0.2 and 0.5 mm, respectively. The difference in the coronal level of osseointegration between the test and control sites was statistically significant. Mineralized bone-to-implant contact was 70.6% ± 10.9% at the test sites and 71.5% ± 9.2% at the control sites. The presence of alveolar mucosa at implants resulted in a more apical position of the coronal level of osseointegration in respect of the implant margin compared with the presence of keratinized mucosa.

Mathematical rationale and results of clinical use of IRIS short implants

The aim of the study was to provide a mathematical justification of the possibility of using 6.5 mm IRIS implants and to evaluate the results of orthopedic treatment in patients with partial loss of teeth. For the calculations was constructed of a composite three-dimensional computer models: the abutment screw-implant-bone. A total of 3 models were prepared: M1-implant in the spongy bone tissue, this model corresponds to the implantation on the HF when replacing one molar; M2-2 implants in the spongy bone tissue located at a distance of 4 mm connected via abutments, this model corresponds to the implantation of RF when replacing two molars; M3-implant in the cortical bone tissue, this model corresponds to the implantation of LF when replacing one molar. Loading of implants was carried out by occlusive force applied to its end surface. The results of the calculations showed that the equivalent stresses and limiting stresses of compression-tension are within the permissible values, which were obtained by us earlier in respect of the irregular implants and are consistent with the results of calculations for other systems of short implants. The clinical part of the work consisted in the treatment of 27 patients with partial loss of teeth, who had 41 iris evolution implants with a diameter of 5 mm, length of 6.5 mm after 3 years, there was a slow bone resorption in the cervical region not exceeding 0.35 mm, which corresponds to generally accepted international standards. During the first three years of operation there were no cases of loss of established implants. Thus, the data of mathematical modeling by finite element method and retrospective three-year analysis of prosthetics on IRIS evolution implants with length of 6.5 mm showed that the use of short implants in the recovery of upper and lower jaw molars is an effective method with a high success rate at long - term and resorption level of 0.34 mm.

Practice-Based Longitudinal Study of Multifactorial Risk Assessment for Periodontal Condition and Survival of Remaining Teeth in Patients with Removable Partial Dentures.

This retrospective cohort study examined factors affecting the periodontal condition and survival of remaining teeth 5 years after removable partial denture (RPD) placement using multivariate analyses. Of 231 patients who received RPDs at Tohoku University Hospital, 108 patients who had agreed to undergo a 5-year follow-up were examined. The outcomes of RPD treatment were assigned to one of three categories: successful (n = 58), remake (n = 36), and failure (n = 14). A total of 80 patients in the successful and remake groups were included in this study. The parameters analyzed to evaluate the periodontal condition were probing depth, Miller index of tooth mobility, and bone resorption level. Criterion variables were the outcome of each periodontal condition, deterioration, and tooth loss. Independent variables were sex, age, smoking habit, number of periodic maintenance appointments, location of RPD, number of abutment teeth, denture base material, design, and existence of a denture in the opposite jaw. Bivariate analyses were performed using chi-square test, and multivariate regression analysis was used to assess significance. Sex and frequency of maintenance care were independently associated with deterioration of the periodontal condition. Sex and existence of a denture in the opposite jaw were independently associated with tooth loss. The findings suggest that periodic maintenance care and condition of the opposite jaw are essential for maintaining the condition of the remaining teeth.

Altered bone microarchitecture and gene expression profile due to calcium deficiency in a mouse model of myeloma

It is not clear why patients with an indolent form of multiple myeloma (MM) develop into an aggressive form with poor prognostic. We investigated the effect of a dietary calcium deficiency on tumor growth, osteolysis and gene expression in the 5T2MM murine model.Two groups of C57BL/KaLwRij mice received 5T2MM cells and started a diet with normal (0.8%; “normal-Ca-MM”) or low calcium content (0.05%; “low-Ca-MM”). Two control groups (without 5T2MM cells) received either a normal or low calcium diet (normal-Ca and low-Ca groups). Tumor growth, osteolysis and marrow gene expression of the Wnt pathway, RANKL and MIP-1α were monitored at 6, 8 and 10 weeks (w) after cell injection.In low-Ca mice, serum level of PTH was higher after 10w; microCT showed trabecular bone loss and decrease of cortical thickness at the tibia. A higher M-protein level was evidenced at 10w and 4 mice developed paraplegia at 8/9w in low-Ca-MM group only. Numerous cortical perforations of the tibia were observed in MM groups with a marked decrease in cortical thickness in low-Ca-MM. At 6w, osteoclast number from the endosteum was significantly higher in low-Ca-MM compared to normal-Ca MM. This observation was not found at 8 and 10w. MicroCT of the lumbar vertebrae showed dramatic bone destruction in the low-Ca-MM group. qPCR revealed no difference in RANKL expression whereas differences were obtained in the expression of Lrp5/Lrp6 and MIP-1α from 6w.A low calcium diet induced higher bone destruction in the tibia and vertebra associated with an earlier decrease in bone formation level and a higher increase in bone resorption level at early time in the MM development.

Perspectives of images superimposition principle use during the registration of peri-implant bone dynamic changes.

Background. Analysis of peri-implant bone level changes with the use of superimposition principle is argumented by the specific remodeling process of bone structure under various mechanical loads, and justified by the possibilities of graphic images modalities provided by cone-beam computer tomography. Objective. To provide a retrospective analysis of superimposition principle use in dental practice according to the literature data and to develop adapted approach for peri-implant bone changes evaluation by a graphical investigation algorithm of CT scanning results. Methods.Retrospective analysis of the literature was provided with the use of Google Scholar and keyword search principle using words "superimposition", "dental", "tomography" as main references. DICOM-files of patients who have undergone the procedure of dental implantation at the University Dental Clinic (Uzhgorod National University) were used as objects of the experimental study. Files of .dcm format were converted to the .stl format with the use of Invesalius 3 software (CentrodeTecnologiadaInformaçãoRenatoArcher). Superimposition of STL model was provided in Geomagic®Control™ by the function of ‘‘Bestfitalignment”. Individualized volumetric bone loss at peri-implant region was calculated by the formula: Vind = Vc.u. * HU (where Vind–an individual volume reduction of bone tissue, an indicator of bone resorption level defined by superimposition principle, and HU - an indicator of bone density defined in terms of Hounsfield units). Results. Principle of image superimposition is a partial representation of the superposition method, which allows to impose the studied areas with the possibility of their segmental analysis and discrete comparison for the visualization and objectification of changes in a particular anatomical region. Proposed algorithm of STL files superimposition formed from DICOM results of CT-scanning provides an adaptive approach for evaluation of individual volume reduction of bone tissue in conventional units due to the offered novel formula. Conclusion. Practical use of super imposition principle can be effective during the verification of residual ridge changes after dental implantation with the ability to register dynamics of bone remodeling processes at different time’s periods after iatrogenic intervention. Thus, the use of such evaluation algorithm may not only deploy settings of bone loss at the peri-implant area, but also expands the opportunities to evaluate the effect of comprehensive iatrogenic and biological factors on circular bone loss around dental implant, which can be registered only with use of computed tomography method.