Contralateral Teeth Research Articles

Dental Anomalies in Parry-Romberg Syndrome: A 40-Year Retrospective Review.

This study investigates crown and root anomalies in patients with Parry-Romberg Syndrome. This is a retrospective review of patients with Parry-Romberg Syndrome who were evaluated at a tertiary care center from 1980-2020. Patients seen in the dental unit from 1980-2020. Seventeen patients with documented Parry-Romberg Syndrome were referred for dental evaluation. All dental anomalies were documented. Root anomalies were assessed using panoramic radiographs and cone beam CT (CBCT) scans to evaluate buccal-lingual, mesio-distal, and axial measurements of hypoplastic teeth, which were compared to those of contralateral teeth. Findings included agenesis (29%, n = 5), hypoplastic teeth (29%, n = 5), delayed canine eruption (24%, n = 4), and mulberry molars (12%, n = 2). Of the five patients with tooth hypoplasia, four had CBCT records and the fifth had panoramic radiographs available for assessment. Axial length was always shorter in hypoplastic teeth relative to contralateral teeth, with differences ranging from 1.2-9.2 mm. Differences in crown size of hypoplastic versus contralateral teeth were unpredictable but always present. Patients with Parry-Romberg Syndrome can have hypoplastic roots with atypical crown morphology. A patient's specific dental anomaly will influence planning and treatment.

Morphological changes of the root apex in anterior teeth with periapical periodontitis: an in-vivo study

IntroductionThe aim was to analyze the morphological changes of root apex in anterior teeth with periapical periodontitis.Methods32 untreated anterior teeth with periapical periodontitis were enrolled, compared with the healthy contralateral teeth. Two-dimensional measurement of Cone-beam computed tomography was used to determine the location and measure diameter of the apical constriction according to Schell’s methods. An open-source software (3D Slicer) was used to reconstruct the teeth. The apical constriction form was analysis according to Schell’s topography. The distances of apical constriction to apical foramen and anatomical apex were measured respectively.ResultsThe difference value between buccolingual and mesiodistal diameter was (0.06 ± 0.09) mm and (0.04 ± 0.04) mm in periapical periodontitis and controls (p < 0.05). The mean distance between apical constriction and anatomical apex was significantly shorter in periapical periodontitis than controls, so was the mean distance of apical constriction to apical foramen. The most common form of apical constriction was flaring (65.6%) in periapical periodontitis.ConclusionsThe anterior teeth with periapical periodontitis had shorter distances of apical constriction to anatomical apex and apical foramen, bigger disparities between the diameters of buccolingual and mesiodistal, and higher proportion of flaring apical constriction.

Correlations between additional roots in maxillary second molars, maxillary first premolars, mandibular first molars and mandibular first premolars: a retrospective cone-beam computed tomography analysis.

This study aimed to determine the prevalence of additional roots in maxillary second molar (MSM), maxillary first premolar (MxFP), mandibular first molar (MnFM) and mandibular first premolar (MnFP) teeth and evaluate the correlations between the number of roots for these teeth. Images of 630 Turkish patients, in which all dental groups examined in the study were present bilaterally, were analyzed using cone-beam computed tomography. The images for the presence of the fourth root in MSMs, third root in MxFPs, distolingual root in MnFMs and complicated-root structure in MnFPs were assessed and divided additional roots into subgroups. The Chi-square test was used for categorical variables such as sex and tooth position. Logistic regression analysis was performed to understand the predictor variability of other teeth in teeth with extra roots. A p < 0.05 was considered statistically significant. Prevalence of the fourth root in MSMs was 1.75%, third root in MxFPs was 6.35%, third root in MnFMs was 3.57%, and complicated root in MnFPs was 21.9%. Positive correlations were observed between MSM, MxFP and MnFP teeth for increasing root numbers (P < 0.05). There was no significant correlation between root numbers of MnFM teeth and other tooth groups (P > 0.05) In the tooth groups examined, there was at least one explanatory variable (except for the right MnFM) tooth in addition to the contralateral tooth for the presence of additional roots.

Positive Osteocalcin Expressions in Periodontium Regenerated by Nano Bioceramics after Orthodontic Tooth Movement

The research is to analyse the immunohistochemical reaction of orthodontic force on the periodontium reformed by nanobiphasic calcium phosphate ceramics (nBCP). Two third incisors were selected randomly and operated as experimental groups in 2 Beagle dogs. In the labial aspects of the third incisors, alveolar bone defects were surgically made and implanted with NBCP. The contralateral teeth in the same jaw did not receive any treatment as control. After 24 weeks, all the third incisors were moved labially. The dogs were euthanized 4 weeks later. The expression levels of osteocalcin were detected by immunohistochemical staining. Positive osteocalcin expressions in regenerated periodontium were observed and compared with the normal periodontium in the control groups. There were no significant differences within and between them. It means the periodontium regenerated by nBCP can bear orthodontic forces with a normal function. Based on these findings, we concluded that nBCP may offer a new bone graft choice for periodontic disease patients who have demands for orthodontic treatment.

Long-term follow-up of mandibular dental arch changes in patients with complete non-syndromic unilateral cleft lip, alveolus, and palate.

BackgroundTreatment of cleft lip and palate (CLP) requires a comprehensive interdisciplinary approach and long-term follow-up. Only a few studies are available that reported on changes after treatment, which showed that in particular the transverse dimension, in patients with CLP is prone to changes after treatment. However, those studies did not pay attention to concomitant changes in the mandibular arch that occur after treatment.ObjectivesTo evaluate mandibular transverse dental arch dimensions and interarch transverse changes in patients with complete non-syndromic unilateral cleft lip, alveolus, and palate (CUCLAP) up to five years after treatment.Material and MethodsRetrospective longitudinal study in 75 consecutive patients with CUCLAP directly after comprehensive treatment (T0), two (T2), and 5 years after treatment (T5). Great Ormond Street, London and Oslo (GOSLON) scores were available for all patients. Three-dimensional scans of all dental casts were made. Inter premolar and intermolar distances between the mandibular contralateral teeth were measured. The modified Huddart Bodenham (MHB index) was applied to assess the transverse interarch relationship. Paired t-tests and ANOVA were used to analyze transverse and interarch transverse changes. Linear regression analysis was done to define contributing factors.ResultsPaired t-tests showed a significant decrease of the mandibular inter first and second premolar distances (p < 0.05) and an increase of the inter second molar distance, whilst the MHB Index deteriorated at all time points for all segments and for the total arch score (p < 0.05). Linear regression showed no significant contributing factors on the decrease of the transverse distances. However, inter arch transverse relationship was significantly affected by age at the end of treatment, missing maxillary lateral incisor space closure, and the GOSLON Yardstick score at the end of treatment (p < 0.05), especially during the first two years after treatment.ConclusionsChanges occurred in the mandibular arch expressed as changes in the transverse dimensions and interarch relationship measured by the MHB Index. A younger age at the end of treatment, space closure for a missing maxillary lateral incisor and a higher GOSLON score at the end of treatment negatively influence the interarch transverse deterioration especially in the first two years after treatment. For the transverse dimensional changes in the mandibular arch such influencing factors could not be determined.

Orthodontic tooth movement alters cementocyte ultrastructure and cellular cementum proteome signature.

Cementum is a mineralized tissue that covers tooth roots and functions in the periodontal attachment complex. Cementocytes, resident cells of cellular cementum, share many characteristics with osteocytes, are mechanoresponsive cells that direct bone remodeling based on changes in loading. We hypothesized that cementocytes play a key role during orthodontic tooth movement (OTM). To test this hypothesis, we used 8-week-old male Wistar rats in a model of OTM for 2, 7, or 14days (0.5N), whereas unloaded contralateral teeth served as controls. Tissue and cell responses were analyzed by high-resolution micro-computed tomography, histology, tartrate-resistant acid phosphatase staining for odontoclasts/osteoclasts, and transmission electron microscopy. In addition, laser capture microdissection was used to collect cellular cementum, and extracted proteins were identified by liquid chromatography coupled to tandem mass spectrometry. The OTM model successfully moved first molars mesially more than 250μm by 14days introducing apoptosis in a small number of cementocytes and areas of root resorption on mesial and distal aspects. Cementocytes showed increased nuclear size and proportion of euchromatin suggesting cellular activity. Proteomic analysis identified 168 proteins in cellular cementum with 21 proteins found only in OTM sites and 54 proteins only present in control samples. OTM-down-regulated several extracellular matrix proteins, including decorin, biglycan, asporin, and periostin, localized to cementum and PDL by immunostaining. Furthermore, type IV collagen (COL14A1) was the protein most down-regulated (-45-fold) by OTM and immunolocalized to cells at the cementum-dentin junction. Eleven keratins were significantly increased by OTM, and a pan-keratin antibody indicated keratin localization primarily in epithelial remnants of Hertwig's epithelial root sheath. These experiments provide new insights into biological responses of cementocytes and cellular cementum to OTM.

Evaluating the Correlation between Periodontal Status of Teeth Adjacent and Contralateral to Implant with Peri-Implantitis - A Retrospective Study

Background: Previous history of periodontitis associated with smoking and poor oral hygiene are considered as one the risk factor for peri-implantitis which in-turn leads to implant failure. Periodontitis is regarded as the most prevalent infectious diseases with around 75% of adults being affected. A similarity between the pathogenesis of periodontitis and peri-implantitis is as a result of intra-oral translocation of periodontal pathogen from teeth showing periodontitis to the peri-implant niche. Aim: The main aim of the study is to evaluate the prevalence of peri-implantitis in patients suffering from periodontitis. Material and Methodology: A retrospective study was conducted in the department of periodontology on 30 patients suffering from periodontitis and with dental implant insertions. In all the patients, periodontal and bone conditions were evaluated. Probing depth, gingival recession, clinical attachment levels, and radiographic bone loss was calculated around the implants, adjacent teeth and contra- lateral teeth to evaluate correlation between periodontitis and implant failures. Results: On evaluation of results with 30 patients, periodontal depth, clinical attachment levels, and gingival recession showed statistically significant around implants when compared with the periodontal parameters around the adjacent teeth and contra-lateral teeth. Non significant results were obtained when radiographic bone loss was evaluated. Conclusion: Within the limitations of the study, it was concluded that dental implant therapy is strongly affected by the periodontal health and health of adjacent teeth plays an important role in determining the failure or success of the implant while contra-lateral teeth have no or minimal relationship between periodontitis and implant failure. Keywords: Implant, Oral Health, Peri-Implantitis, Periodontitis, Translocation.

Impact of 0.12% Chlorhexidine Gluconate Mouthwash on Peri-Implant Mucositis and Gingivitis After Nonsurgical Treatment: A Multilevel Analysis.

This study investigated the impact of 0.12% chlorhexidine gluconate mouthwash on dental implants with periimplant mucositis and contralateral teeth with gingivitis at 6 months of follow-up after nonsurgical treatment. This was a secondary analysis of data from a previous controlled, randomized, double-blinded clinical trial of 30 patients diagnosed with peri-implant mucositis and gingivitis in contralateral teeth, at 6 months following treatment. Patients were randomly assigned into a test group (basic periodontal therapy + 0.12% chlorhexidine mouthwash) or a control group (basic periodontal therapy + placebo). Therapy consisted of an adaptation of the full-mouth scaling and root planing protocol. The clinical parameters of visible Plaque Index, Gingival Bleeding Index, probing depth, bleeding on probing, keratinized mucosa width, and gingival and peri-implant phenotype were evaluated at baseline and at 1, 3, and 6 months posttherapy. Data were analyzed using Poisson multilevel regression analysis with a significance level of .05. The study analyzed 47 implants and contralateral teeth (376 sites) in the test group and 49 implants and contralateral teeth (392 sites) in the control group. No differences were found between the groups at the patient level. At the site level, the teeth and implants presented statistical differences in bleeding on probing, probing depth, and keratinized mucosa width at 3 months for both treatment groups. However, no difference was observed in bleeding on probing in the test group (P = .484) at 6 months, whereas the control group demonstrated increased bleeding on probing (indicating more inflammation) at implant sites than at teeth sites (P = .039). Additionally, implant sites with a thin peri-implant phenotype (P < .001) and located posteriorly (P = .002) presented greater inflammation. Use of a 0.12% chlorhexidine mouthwash for 14 days was beneficial for implant sites with peri-implant mucositis, compared to contralateral teeth sites with gingivitis, as indicated by the reduced percentage of teeth with bleeding on probing.

Impact of interproximal composite restorations on periodontal tissue health: Clinical and cytokine profiles from a pre-post quasi-experimental study.

The aim of this study is to clinically and molecularly evaluate the effect of an interproximal iuxta/subgingival direct composite restoration on periodontal tissue healing. Individuals in need of a posterior iuxta/subgingival interproximal restoration were consecutively enrolled. After enrollment, a test (site with tooth decay) and a control site (intact contralateral tooth) were identified. After a periodontal examination (probing depth [PD], clinical attachment level, recession, plaque, and bleeding on probing [BOP]) and a sampling of gingival crevicular fluid, the composite restoration was performed (T0 ). Clinical and molecular assessments were repeated at 3 (T3 ), 6 (T6 ), and 12 (T12 ) months after the restoration. Intragroup pre-post comparisons for quantitative variables were performed either through one-way ANOVA or Kruskal-Wallis test. A multivariate linear regression analysis was then modeled. With α = 0.05, a power of 80% will be reached with the inclusion of 41 individuals. Biometric parameters demonstrated an increased mean PD (ΔPDT0 -T12 = -0.83 mm; P = 0.001) and loss of attachment (AL) (ΔCALT0 -T12 = -0.91 mm; P = 0.005) in the test site at 12 months. Accordingly, in the final multivariate regression model the radiographic distance between the bone crest and the restorative margin at baseline accounted for the dependent variable "attachment loss (AL)" (ΔCALT0 -T12 ) (P <0.05). Iuxta/subgingival interproximal restorative margins jeopardized clinically and molecularly the periodontal tissue healing at least up to 1 year of follow-up.

Soft and Hard Tissue Changes Subsequent to Spontaneous Healing of the Extraction Sockets Using Cone-Beam Computed Tomography: A Cross-Sectional Study.

This study sought to compare the thickness of hard and soft tissues between edentulous and contralateral tooth sites. This split-mouth study evaluated 153 partially edentulous patients. The measurements were made on cone-beam computed tomography (CBCT) scans. The soft tissue thickness was measured at the cementoenamel junctional (CEJ) level, and at 2, 4, and 6mm apical to the CEJ in the facial and palatal aspects. The bone thickness of the opposite quadrant was also recorded at 2, 4, and 6mm apical to the CEJ. The Mann-Whitney U test and the Spearman's rank correlation coefficient were applied for further statistical analyses. At the edentulous sites, significant soft tissue loss was noted at the CEJ level (p < 0.0001) and a considerable gain was noted at 2, 4, and 6mm apical to the CEJ (p = 0.004, p < 0.0001, p ≤ 0.0001, respectively). A significant hard tissue loss was noted at 2mm apical to the CEJ but a significant hard tissue gain was observed at the edentulous sites (p < 0.0001). The soft tissue gain at 6mm apical to the CEJ was significantly associated with an increase in buccolingual diameter (p = 0.004) while the hard tissue loss at 2mm apical to the CEJ was significantly correlated with a reduction in buccolingual diameter (p = 0.020). Different amounts of tissue thickness alterations occurred in different levels of socket.

Evaluation of patient satisfaction and the color difference between natural teeth and all-ceramic crowns fabricated from "Celtra press" treated with different surface finishing protocols. (Randomized controlled clinical trial)

All studies agree that glazing can produce a smooth porcelain surface, but although the glaze is an important factor in esthetics, with respect to light reflection, it can frequently change the color value of the restorations, reflecting more light than the natural teeth, thus creating an artificial effect on these restorations. A number of more recent studies have suggested that a polished surface may be as acceptable as a glazed surface. Many ceramists prefer polishing instead of glazing to control the surface luster. Other studies have reported no significant differences between polished and glazed surfaces.Since studies addressing the effect of surface finishing protocols on the color of ZLS ceramics are rare, thus our study is important to investigate this issue. Methodology: 20 teeth esthetic zone requiring full - coverage crown -with their contralateral are sound and not severely discolored - were prepared to receive an all -ceramic crown. The crowns are divided into two groups: Group I: Teeth received crowns fabricated from glazed Celtra Press ceramic Group II: Teeth received crowns fabricated from polished Celtra Press. The color difference ΔE was measured using an intraoral spectrophotometer and evaluated for each group. Shade matching to the contralateral tooth was evaluated by 2 experienced prosthodontists according (USPHS) criteria. Patient satisfaction of the two groups assessed using the (VAS) scale which is Binary and documented in the chart. Results: Patient satisfaction was graded according to the (VAS) scale. There was no statistically significant difference between (Group I) and (Group II). The color change was recorded according to the (ΔE), the polished Celtra Press group recorded statistically non-significant higher color changes than the glazed Celtra Press group. shade matching was graded according to USPHS, where in Glazed Celtra Press group most of the patients stated Alpha score (80%) while minority showed Bravo score (20%). In the Polished Celtra Press group, all of the patients informed Bravo score100%. Conclusion: Within the limitations of this clinical study: Glazed and polished Celtra Press full coverage restorations revealed excellent patient satisfaction. Glazed celtra restorations have a clinically more acceptable shade matching.

Evaluation of the Marginal Location and Periodontal Health in Crowns and Bridges – A Patient Preference Based Study

OBJECTIVE: The objective of this paper was to evaluate the marginal location preference and periodontal health in extra coronal restoration of anterior and posterior teeth. METHODOLOGY: In this prospective case control study, a total of 652 patients who had crown and bridge for not less than six months were included. The gingival margin location preference and reasons behind choosing a particular gingival margin was asked from the patients. Additionally, the teeth with and without restoration were also examined for periodontal health. Split mouth technique was used as unrestored, healthy contra lateral teeth in the same individual served as controls. Descriptive statistics and Chi square test were used for analysis to formulate the results. RESULTS: Ironically, 92% patients were not given a chance by their dentist to give input about margin location preference. The majority of patients preferred equi gingival margin for their anterior crowns 495 (75.92%) and supra gingival margin 586 (89.87%) for their posterior teeth, with esthetics 547 (83.89%) and hygiene 599 (91.87%) respectively being the most common reasons for selecting the particular margin location. The clinical examination revealed that supra gingival and equi gingival margins demonstrated superior gingival health indices as compared to subgingival margins CONCLUSION: This study concluded that the supra gingival and equi gingival margins demonstrated superior gingival health indices as compared to subgingival margin and in order to achieve optimal periodontal health and patient satisfaction the health professionals should wisely consider the margin location and involve the patient in treatment decisions wherever possible. KEY WORDS: Crown and Bridge, Margin location, Patient preference, Periodontal Health.

Does the pre-operative buccal soft tissue level at teeth or gingival phenotype dictate the aesthetic outcome after flapless immediate implant placement and provisionalization? Analysis of a prospective clinical case series

BackgroundImmediate implant placement (IIP) often is related to mid-buccal recession in literature. To draw conclusions about the behavior of the soft tissues following IIP, pre-operative aesthetic measurements have to be taken into account. The aim of analysis of these prospective clinical case series data was to elucidate whether the pre-operative buccal soft tissue level (STL) or gingival phenotype influence the 1-year pink aesthetic outcome after performing flapless immediate implant placement and provisionalization (FIIPP) maxillary incisor cases.Materials and methodsIn 97 patients, a maxillary incisor was replaced performing FIIPP. STL and phenotype were analyzed on light-photographs made pre-operatively (T0), direct post-operatively (T1), after placement of the permanent crown (T2), and 1 year post-operatively (T3). To investigate if a pre-operative buccal soft tissue deficiency or excess influenced the total pink esthetic score (total-PES) per patient at T3, PES-3 was modified by adding a minus (“−”) or plus (“+”) in case of a STL-deficiency or excess, respectively.ResultsPre-operatively, 40% of the cases showed a mid-buccal recession (STL-deficiency), 19% STL-excess, while in 41% an equal level in comparison with the contra-lateral tooth was observed (STL-neutral). One year post-operatively, 79% (31/39) of the recession cases showed soft tissue gain, while STL-excess cases showed the highest rate of soft tissue reduction (94%; 17/18). This resulted in a decrease of soft tissue recessions and excesses (to 26% and 4%, respectively), and an increase of ideal STL (PES-3-score 2) to 70%. The 1-year aesthetic outcome was not statistically different (p = 0.577) between patients with a pre-operative soft tissue recession (mean T3 total-PES = 12.18) or STL excess (mean T3 total-PES = 11.94). Of the total population, 71 patients with a thin, and 26 with a thick phenotype were evaluated. No statistical difference (p = 0.08) was present in aesthetic outcome between the two phenotypes (thin mean T3 total-PES = 12.30, thick mean T3 total-PES = 11.65).ConclusionRegardless of phenotype, preoperative soft tissue recession, or excess, comparable high aesthetic outcomes were achieved 1 year post-operatively.Trial registrationEthical approval was obtained and registered on 20 October 2015 (NTR5583/NL4170).

Influence of Dental Pulp Harvesting Method on the Viability and Differentiation Capacity of Adult Dental Pulp-Derived Mesenchymal Stem Cells.

Objective To compare two pulp harvesting methods for stem cell expansion, namely, conservative pulpotomy and pulpectomy from exodontia. Method Ten freshly extracted sound third molars from five patients were selected. Five were used in the control group, where pulp harvesting was performed by exodontia and the remaining teeth were used in the test group, where the pulp was harvested by conservative pulpotomy (preserving the tooth). This was a split-mouth design study, where a third molar from one side was randomly allocated into the test group and the contralateral tooth in the control group. After pulp harvesting, the following evaluations were performed: cell morphology, sterility test, immunophenotyping, differentiation assays, first pass live cell counts, time to cryopreservation, and total number of expanded cells at the end of the fourth pass. Results Regarding morphology, the cells from both groups presented a fibroblastic phenotype. All samples were sterile. Immunophenotyping demonstrated a positive expression for CD105, CD90, and CD73 and negative expression for CD45 in both groups. Differentiation assays were positive for osteogenic and chondrogenic differentiation in both groups. Regarding live cell counts in the first passage, the control group had 95.8% live cells in the total count and the test group 91.2% (p < 0.05). The time required for cryopreservation was equivalent in both groups 51.6 days and 52.6 days, respectively (p > 0.05). The total number of cells at the end of the fourth passage was 5,286,782 and 5,736,862, respectively (p > 0.05). Conclusion These results suggest that adult stem cell harvesting from conservative pulpotomy is as effective as the traditional exodontia-based method.

Systemic administration of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4)-Ig abrogates alveolar bone resorption in induced periodontitis through inhibition of osteoclast differentiation and activation: An experimental investigation.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a critical immunoregulatory molecule expressed on T cells. CTLA-4 also binds to the surfaces of monocytes and macrophages, precursors of osteoclasts. Research on rheumatoid arthritis demonstrated that CTLA-4suppresses inflammation and bone resorption. However, its effects on alveolar bone have yet to be understood. The purpose of this study was to investigate the role and potential mechanism of CTLA-4 in bone resorption in periodontitis. In vivo, the effects of systemic administration of CTLA-4 immunoglobulin fusion protein (CTLA-4-Ig) on alveolar bone resorption were investigated using a periodontitis mouse model. A total of 20 C57BL/6J mice were randomly assigned to two groups according to the administration modes. Periodontitis was induced by placing a ligature around the left maxillary second molar. The contralateral tooth was left un-ligated. In the CTLA-4-Ig (+) group, CTLA-4-Ig was administered by intraperitoneal injection at 1 and 3days after ligature placement. Animals in the CTLA-4-Ig (-) group were given only phosphate-buffered saline each time. At 5days after ligature placement, bone resorption was assessed by micro-computed tomography and histological examination, and the prevalence of osteoclast-like cells was assessed by tartrate-resistant acid phosphatase (TRAP) staining. In vitro, the effects of CTLA-4-Ig on osteoclasts were evaluated. Viability of RAW 264.7 cells treated with receptor activator of nuclear factor-κB ligand (RANKL) and CTLA-4-Ig was tested by WST-1 assay. Osteoclast-like cells were enumerated by TRAP staining, and osteoclast activity was evaluated by resorption pit assay. Gene expression levels of osteoclast differentiation markers (macrophage-colony stimulating factor receptor, carbonic anhydrase II, cathepsin K, and Trap) and protein phosphatase 2A (PP2A), a major serine-threonine phosphatase, were assessed by quantitative real-time polymerase chain reaction. The effect of CTLA-4-Ig on the nuclear factor-κB (NF-κB) activation was assessed by enzyme-linked immunosorbent assay. In vivo, ligature-induced bone resorption and the numbers of osteoclast-like cells were significantly decreased by the administration of CTLA-4-Ig. In vitro, treatment with RANKL and CTLA-4-Ig had no significant effect on cell viability. CTLA-4-Ig significantly reduced the prevalence and activation of osteoclast-like cells and decreased the expressions of osteoclast differentiation markers, compared with the RANKL-treated control. CTLA-4-Ig significantly suppressed RANKL-induced phosphorylation of NF-κB p65 but increased PP2A expression. These results suggest that CTLA-4-Ig abrogates bone resorption in induced periodontitis, possibly via inhibition of osteoclast differentiation and activation. The regulation of the NF-κB pathway and PP2A expression may be one mechanism by which CTLA-4-Ig suppresses osteoclast behavior.

Randomized clinical trial of zirconia and polyetheretherketone implant abutments for single-tooth implant restorations: A 5-year evaluation

Statement of problemTitanium-supported polyetheretherketone (PEEK) abutments provide an economic alternative to zirconia abutments in esthetically important areas. Research comparing the performance regarding esthetics, longevity, and biologic parameters of PEEK abutments is lacking. PurposeThe purpose of this clinical study was to determine whether PEEK implant abutments provide similar esthetic and biologic parameters and survival rates as zirconia implant abutments. Material and methodsForty participants (age 20 to 50 years) receiving maxillary anterior and premolar implants were enrolled in the study and randomly assigned into 1 of 2 groups: Group PEEK (20 titanium-supported PEEK abutments) and group ZIR (20 zirconia abutments). Both groups were restored with pressed lithium disilicate ceramic crowns. Technical, biologic, and esthetic evaluation was performed at baseline and at 1, 3, and 5 years. The probing pocket depth, plaque control record, and bleeding on probing were recorded at the abutments (test) and compared with those at the corresponding contralateral teeth (control) and also between the 2 test groups. Standardized digital radiographs of the implants were made, and the bone level was recorded with the implant shoulder as the reference on the mesial and distal sides. The color difference between the peri-implant mucosa and control teeth gingiva and the discoloration of the implant crowns were determined with a spectrophotometer. The Student unpaired t test and repeated-measure ANOVA were used to statistically analyze the data (α=.05). ResultsFrom the 5-year evaluation, both PEEK and zirconia abutments with ceramic crowns showed 100% survival rate without any fracture or restoration loss. Differences in the biologic parameters of zirconia and PEEK abutments were statistically similar: mean probing pocket depth (group ZIR: 2.32 ±0.50 mm, group PEEK: 2.13 ±0.60 mm); mean plaque control record (group ZIR: 0.19 ±0.19, group PEEK: 0.15 ±0.17); and mean bleeding on probing (group ZIR: 0.12 ±0.11, group PEEK: 0.08 ±0.12). The mean marginal bone loss at 5 years was similar for implants supporting zirconia and PEEK abutments: mean mesial bone level (group ZIR: 1.8 ±0.5 mm; group PEEK: 1.9 ±0.6 mm), and mean distal bone level (group ZIR: 1.7 ±0.6 mm, group PEEK: 1.8 ±0.3 mm). The initial color difference (ΔE) between the peri-implant mucosa and gingiva of the analogous contralateral teeth diminished over time. No discoloration of the definitive restoration supported by PEEK or zirconia was detected over 5 years. ConclusionsAt the 5-year evaluation, zirconia and PEEK abutments exhibited the same survival rate with similar biologic and esthetic outcomes.

Unprepared surface areas, accumulated hard tissue debris, and dentinal crack formation after preparation using reciprocating or rotary instruments: a study in human cadavers.

This study using contralateral teeth from human cadavers assessed the amount of unprepared wall surface areas (USA), accumulated hard tissue debris (AHTD), and dentinal crack formation after root canal preparation using either reciprocating or rotary instruments. Incisors with a single root canal from 11 human mandibles had their root canals prepared with Reciproc or Mtwo. Each contralateral tooth was treated with one of the test instruments in order to create matched pairs. Micro-CT scans were taken before and after preparation to instrument sizes 40 and 50 in both groups. USA and AHTD were evaluated in the full canal length or the apical portion only. Crack formation was also evaluated in the full root length. After size 40, no significant differences in USA and AHTD were observed in the full canal length (P > .05). Separate analysis of the apical 4-mm canal revealed no difference in AHTD, but significantly more USA with Mtwo than Reciproc (P < .05). After size 50, the amount of USA was similar between groups both in the full canal and in the apical canal (P > .05). More AHTD were observed in the full canal after using Mtwo size 50 (P < .05), but no difference occurred in the apical canal only (P > .05). Intragroup analyses showed a significant decrease of USA and a significant increase of AHTD when preparation size increased from 40 to 50 (P < .05). In teeth without any pre-existing detectable dentinal defect (n = 38), crack formation occurred in 4 teeth, 2 from each preparation system. Reciproc instrument size 40 resulted in more prepared areas in the apical canal than Mtwo instrument of the same size. However, the amount of AHTD did not differ between them at this file size. Canal enlargement to size 50 prepared more walls but created more debris. Dentinal defects were produced after preparation with both systems.

Variation in Dental Occlusal Schemes Two Years After Placement of Single-Implant Posterior Crowns: A Preliminary Study

Some authors have recommended that implant-supported single crowns should only contact during heavy clenching. However, a lack of occlusal contact with moderate clenching may cause supraeruption of antagonist natural teeth. The main objective of this study was to assess changes in the occlusal contacts of posterior implant-supported single crowns with natural antagonist teeth 2 years after placement. The occlusal schemes of 14 patients who received 16 implant-supported single crowns in molar and premolar regions were assessed in this prospective study. Just after crown placement, at 6 months and after 2 years, a silicone maxillomandibular relationship and T-scan records were obtained during the intercuspal position with light and heavy clenching, determined using near half of the maximum force and maximum force, respectively. Occlusal contacts were assessed quantitatively and qualitatively in the implant-supported single crowns, contralateral tooth, and adjacent tooth; the latter 2 were used as controls. After 6 months and 2 years, no significant variations were observed in any region of the occlusal scheme in any assessments, including silicone record or T-Scan, using light or heavy clenching, and qualitative or quantitative occlusal contact assessment. In this preliminary study, the occlusal scheme did not vary at the intercuspal position 2 years after placing posterior implant-supported single crowns.

The application of individualized abutment-crown integrated provisional restoration in optimizing the peri-implant soft tissue contour in the esthetic zone.

This article introduced a modified method to fabricate an individualized abutment-crown integrated provisional restoration for single-tooth implant restoration in the esthetic zone, which created a satisfactory peri-implant soft tissue architecture. Three months after the implant placement, the individualized abutment-crown integrated provisional restoration was designed and fabricated in the laboratory, by referring to the profile of natural contra-lateral tooth digitally, and seated on the implant afterwards. The peri-implant soft tissue architecture was evaluated and the Pink Esthetic Score (PES) was recorded. The provisional restoration stayed on the implant for 3 months until the individualized definitive ceramic abutment and crown were fixed on the implant. This protocol provided an alternative solution for shaping the peri-implant soft tissue morphology in the esthetic zone by using an individualized abutment-crown integrated provisional restoration and showed promising effect on the esthetics of anterior single-tooth implant restoration. The individualized abutment-crown integrated provisional restoration whose emergence profile mirroring that of the natural contra-lateral tooth, was designed with the help of computer-aided design-manufacture (CAD/CAM). It may help shaping the peri-implant soft tissue in the esthetic zone with merits of saving amount of hand labor of technicians as well as clinicians, and reducing the visits of patients.

Quantitative analysis on the wear of monolithic zirconia crowns on antagonist teeth

BackgroundThe present study aimed to quantitate the wear of the highly transparent Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) ceramic monolithic zirconia crown on the enamel in vivo and discuss the prone position of the wear and the underlying mechanism.Methods A total of 43 patients with 43 posterior teeth were selected for full zirconia crown restoration and examined immediately, at 6 months, and at 1 year after restoration. During the follow-up visit, the fine impression of the patients’ monolithic zirconia crowns, the antagonist teeth, the corresponding contralateral natural teeth, the super plaster cast, and epoxy resin model was ontained. The model of epoxy resin was observed under a stereo microscope, and the microstructure parts were observed under a scanning electron microscope.ResultsAfter 1 year, the mean depth and volume of wearing of the monolithic zirconia crown were the smallest (all P < 0.01), while those of the antagonist teeth were significantly larger than those of the natural teeth (P < 0.0001), and no significant difference was found among the natural teeth (P = 0.3473, P = 0.6996). The amount of wear after one year was remarkably higher than that at 6 months (P < 0.0001). The microscopic observation revealed the tendency of wearing of the monolithic zirconia crown on the antagonist teeth at the protruding early contact points. Electron micrographs of tooth scars showed that the wearing mechanism of the monolithic zirconia crown on natural teeth was mainly abrasive and fatigue wear.ConclusionsAlthough the self-wearing is insignificant, the monolithic zirconia crown can cause wear of the antagonist teeth via occlusal or early contact significantly; the amount of wearing is higher than that of natural teeth and increases over time. The wearing mechanism is mainly abrasive and fatigue wear.