Forced eruption in impacted teeth: analysis of failed cases and outcome of re-operation.

BACKGROUND: Forced eruption of an impacted tooth usually requires surgical and orthodontic interventions to successfully bring the tooth into the dental arch. The clinical time required for a forced eruption is difficult to predict before treatment begins and success rates are affected by several factors before and after an eruption. This study was conducted to identify factors that affect the success of forced eruption, the duration of orthodontic treatment of impacted teeth, and the reasons for re-operation and forced eruption failure in a various teeth and cases. METHODS: In this retrospective study, the records regarding the forced eruption of 468 teeth in 371 patients from June 2006 to May 2020 at the Advanced General Dentistry Department of Yonsei University Dental Hospital were initially examined. The records of 214 teeth in 178 patients who completed orthodontic treatment were included in the analysis. Data on patient demographics, tooth characteristics, orthodontic treatment duration, re-operations, and failures were collected from electronic medical records. RESULTS: There was a significant difference in age between the success and failure forced eruption. Factors significantly affecting treatment duration were apex formation, position, rotation, and re-operation. Re-operation had a 96% success rate. The average orthodontic treatment duration was 29.99 ± 16.93 months, but the average orthodontic treatment duration for teeth that undergone re-operation was 20.36 ± 11.05 months, which was approximately 9 months shorter. Additionally, there was an interaction effect between rotation and re-operation on the duration of orthodontic treatment. The causes for failure of forced eruption in 6 cases were ankyloses (3 cases), incomplete alignment with the normal dental arch (2 cases), and a significant deviation in the impacted tooth's location (1 case). CONCLUSIONS: To increase the success rate of forced eruption, age should be considered as a priority, and in order to predict the treatment period, the apex formation status, position in the arch, and rotation should be considered in addition to age. When determining re-operation, considering factors such as ankylosis, root curvature, and apex formation can help in the success of orthodontic treatment.

Combined distalization and lingual cortex remodeling during mandibular growth for facial profile improvement: a case report.

Borderline crowding poses a challenge in deciding whether or not to prescribe premolar extraction. This case report describes the two-phase nonextraction orthodontic treatment of an 11-year-old girl with a hyperdivergent skeletal Class I pattern exhibiting anterior crowding and moderate lip protrusion. The initial phase of treatment included maxillary and mandibular expansion to correct the transverse discrepancy as an early intervention. Subsequently, comprehensive treatment was initiated at the age of 13 years, with fully erupted permanent second molars and growth potential remaining. Phase II treatment involved a second round of maxillary expansion, followed by simultaneous bimaxillary total arch intrusive distalization, using interradicular, temporary skeletal anchorage devices to correct dental crowding and improve the facial profile. Although the limited retromolar space posed a challenge to mandibular tooth distalization, gradual bone remodeling was observed in the lingual cortex of the mandibular body, enabling sufficient orthodontic tooth movement without noticeable side effects. After 4 years 3 months of treatment, her dental crowding was relieved, with significant improvement in the facial profile and proper occlusion. The treatment outcomes remained stable 2 years 4 months after retention.

Occlusive membranes for guided regeneration of inflamed tissue defects.

Guided bone regeneration aided by the application of occlusive membranes is a promising therapy for diverse inflammatory periodontal diseases. Symbiosis, homeostasis between the host microbiome and cells, occurs in the oral environment under normal, but not pathologic, conditions. Here, we develop a symbiotically integrating occlusive membrane by mimicking the tooth enamel growth or multiple nucleation biomineralization processes. We perform human saliva and in vivo canine experiments to confirm that the symbiotically integrating occlusive membrane induces a symbiotic healing environment. Moreover, we show that the membrane exhibits tractability and enzymatic stability, maintaining the healing space during the entire guided bone regeneration therapy period. We apply the symbiotically integrating occlusive membrane to treat inflammatory-challenged cases in vivo, namely, the open and closed healing of canine premolars with severe periodontitis. We find that the membrane promotes symbiosis, prevents negative inflammatory responses, and improves cellular integration. Finally, we show that guided bone regeneration therapy with the symbiotically integrating occlusive membrane achieves fast healing of gingival soft tissue and alveolar bone.

Dimensional accuracy, mechanical property, and optical stability of zirconia orthodontic bracket according to yttria proportions.

This in vitro study evaluated comprehensively the performances of zirconia brackets with varying yttria proportions in manufacturing advanced orthodontic brackets. Three experimental groups of zirconia brackets were fabricated using yttria-stabilized zirconia (YSZ) materials with different yttria proportions-3 mol% yttria (3Y-YSZ), 4 mol% yttria (4Y-YSZ), and 5 mol% yttria (5Y-YSZ) (Tosoh Ceramic, Japan). A polycrystalline alumina ceramic bracket (3M™ Clarity™ Advanced, MBT 0.022-in. slot) was employed as the control group. Morphological properties, including slot surface structure and dimensions, were examined using scanning electron microscopy and surface profiler analysis. Manufacturing accuracy was assessed with root mean square calculations of trueness and precision. Mechanical properties were tested, encompassing static and kinetic frictional resistance (FR) and fracture strength. Optical stability was evaluated through 20,000 cycles of thermocycling and a 7-day immersion in various coloring agents. Within the limitations of this study, zirconia brackets containing 3 to 5 mol% YSZ presented enhanced reliability in terms of dimensional accuracy and demonstrated favorable optical stability. Notably, owing to its advantageous mechanical properties, the 3Y-YSZ variant showed remarkable potential as an advanced material for fabricating orthodontic brackets.

A novel orthodontic adhesive containing zinc-doped phosphate-based glass for preventing white spot lesions.

OBJECTIVES: This study aimed at demonstrating the remineralization effect of the enamel around the brackets to aid reduction in white spot lesions (WSLs) with use of zinc-doped phosphate-based glass (Zn-PBG) containing orthodontic adhesives. METHODS: Zn-PBG powder was synthesized, and particle morphology, size, and density were evaluated. Orthodontic adhesives with increasing loading percentage of Zn-PBG powder were prepared: ZnPG3 (3 wt.%), ZnPG6 (6 wt.%), and ZnPG9 (9 wt.%). Brackets were bonded on the etched enamel surface and stored in distilled water (DW) for 1 h. Following, Shear bond strength (SBS) along with adhesive remnant index were analyzed. The release of calcium (Ca), phosphorus (P), and zinc (Zn) from adhesive specimens in DW was evaluated after 7, 15 and 30 days of immersion. The remineralization effect was confirmed by microhardness and surface morphology analysis with scanning electron microscopy. RESULTS: The SBS value was observed between 20 and 22 MPa on enamel surface. The concentration of Ca, P and Zn released in DW increased with loading percentage of Zn-PBG. The microhardness increased in the experimental groups after immersion in artificial saliva for 7 days. Apatite-like crystal formation was observed after 30 days in the ZnPG 9 group. CONCLUSIONS: The orthodontic adhesive containing Zn-PBG with an optimal SBS performance has an enamel remineralization effect, and therefore can aid in prevention of WSLs. CLINICAL SIGNIFICANCE: The orthodontic adhesive containing Zn-PBG is clinically advantageous as it can promote remineralization and resist the formation of WSLs that may occur during orthodontic therapy.

Quantitative light-induced fluorescence enables effective detection of orthodontic adhesive residues in diverse environments.

BACKGROUND: Adhesive remnants post-orthodontic treatment might have deleterious effects on oral health, including enamel demineralization, plaque accumulation, and elevated risk of caries development. The aim of this study was to identify and characterize adhesive residues in an ex vivo environment rich in salivary microbiota using quantitative light-induced fluorescence (QLF) technology. METHODS: Disc-shaped adhesive samples with thickness ranging from 800 to 100 µm were prepared using GC Ortho, GOTO, T Orthobond, and Transbond XT and subsequently evaluated utilizing a QLF system. Bovine teeth containing GC Ortho and GOTO adhesives and isolated human premolar teeth bonded with brackets were subjected to a 10-day incubation in an artificial saliva environment. Daily imaging was conducted using QLF during incubation. Data with ΔR > 30% and simple hygiene score (SHS) were obtained with a software for further analysis. RESULTS: Fluorescence intensity exhibited significant differences among the four orthodontic adhesives (p < 0.05). Results of incubation in artificial saliva revealed that red fluorescence surrounding the adhesive on the tooth surface was distinctly observable from day five onwards, with ΔR > 30% and SHS levels higher than those of the control group without adhesive (p < 0.05). Observation of fluorescence images of isolated human premolar teeth with bonded brackets indicated that red fluorescence was primarily present around the brackets. CONCLUSIONS: Application of QLF is efficacious in identifying and demarcating adhesive residues within an environment rich in salivary microbiota.

Effect of strontium substitution on functional activity of phosphate-based glass.

Phosphate-based glass (PBG) is a bioactive agent, composed of a glass network with phosphate as the primary component and can be substituted with various therapeutic ions for functional enhancement. Strontium (Sr) has been shown to stimulate osteogenic activity and inhibit pro-inflammatory responses. Despite this potential, there are limited studies that focus on the proportion of Sr substituted and its impact on the functional activity of resulting Sr-substituted PBG (PSr). In this study, focusing on the cellular biological response we synthesized and investigated the functional activity of PSr by characterizing its properties and comparing the effect of Sr substitution on cellular bioactivity. Moreover, we benchmarked the optimal composition against 45S5 bioactive glass (BG). Our results showed that PSr groups exhibited a glass structure and phosphate network like that of PBG. The release of Sr and P was most stable for PSr6, which showed favorable cell viability. Furthermore, PSr6 elicited excellent early osteogenic marker expression and inhibition of pro-inflammatory cytokine expression, which was significant compared to BG. In addition, compared to BG, PSr6 had markedly higher expression of osteopontin in immunocytochemistry, higher ALP expression in osteogenic media, and denser alizarin red staining in vitro. We also observed a comparable in vivo regenerative response in a 4-week rabbit calvaria defect model. Therefore, based on the results of this study, PSr6 could be identified as the functionally optimized composition with the potential to be applied as a valuable bioactive component of existing biomaterials used for bone regeneration.

Three-dimensional micromorphology of human midpalatal suture and pterygomaxillary articular complex.

BACKGROUND: Sutures exist in the craniofacial area, and the pattern of maturation and synostosis of facial sutures is largely unknown. METHODS: For a comprehensive understanding of the three-dimensional circummaxillary suture micromorphology, human midpalatal suture (MPS) and pterygomaxillary articular complex from eight subjects' (five males, three females, 72-88 years old) autopsies were longitudinally scanned with microcomputed tomography. Additional histology was performed for hematoxylin and eosin staining. Sutural micromorphology was assessed by interdigitation index (II), obliteration index (OI) and obliteration number. Intergroup comparisons were performed with Kruskal-Wallis and Mann-Whitney U with Bonferroni correction (α = 0.005). Correlation with anteroposterior and craniocaudal gradients was assessed with Spearman's correlation test (α = 0.05). RESULTS: Maxillary region of MPS presented a higher II 1.50 (0.61) and obliteration number per slice 8 (9) (P < 0.005). OI was increased in palatomaxillary 35% (47%) followed by pterygopalatine suture 25% (49%) (P < 0.005). The II and OI of the MPS exhibited only a weak anteroposterior gradient, with relatively low correlations. Obliteration areas were found sporadically along the entire MPS. CONCLUSIONS: Based on these findings, it is conceivable that the success of nonsurgical maxillary expansion largely depends on individual variations in sutural morphology and maturation rather than appliance design.

Pattern of lip retraction according to the presence of lip incompetence in patients with Class II malocclusion.

Objective: The aim of this retrospective study was to compare changes in hard tissue and soft tissue after the four first premolars were extracted with anterior teeth retraction according to the presence or absence of lip incompetence. Methods: Patients who underwent the four first premolars were extracted with anterior teeth retraction were divided into competent (n = 20) and incompetent lip (n = 20) groups. Cephalometric measurements for hard tissue and soft tissue changes were performed pre-treatment and post-treatment. Results: In the competent group, the upper and lower lips retreated by 2.88 mm and 4.28 mm, respectively, and in the incompetent group by 4.13 mm and 5.57 mm, respectively; the differences between the two groups were significant (p < 0.05). A strong positive correlation between retraction of the upper lip and upper incisors was observed in both groups (p < 0.05), whereas a correlation between retraction of the lower lip and lower incisors was only found in the incompetent group. A simple linear regression analysis showed that the pattern of lip retraction following the retraction of the anterior teeth was more predictable in the incompetent group than in the competent group. Conclusions: These findings suggest that the initial evaluation of lip incompetence in patients with skeletal Class II is essential for the accurate prediction of the soft tissue changes following retraction of the anterior teeth in premolar extraction treatment. Therefore, sufficient explanation should be provided during patient consultations.

Differences in the 3-dimensional aging changes of the lips among female adults with skeletal Class I, II, and III malocclusion.

INTRODUCTION: The objective of this study was to evaluate and compare the 3-dimensional (3D) aging changes of the lips among adult skeletal Class I, II, and III malocclusion. METHODS: Female adult orthodontic patients aged 20-50 years with pretreatment cone-beam computed tomography scans were retrospectively classified according to age (20s [20-29 years], 30s [30-39 years], and 40s [40-49 years]) and then subclassified by malocclusion into skeletal Class I, II, and III relationship (9 groups; n = 30 per group). Positional differences in midsagittal and parasagittal soft-tissue landmarks and 3D morphologic aging changes of the lips were evaluated using cone-beam computed tomography scans. RESULTS: Labiale superius and cheilion for patients in their 40s indicated a significant downward and backward position compared with those in their 20s, regardless of skeletal classifications (P <0.05). Accordingly, the upper lip height decreased, and the mouth width increased significantly (P <0.05). For Class III malocclusion, the upper lip vermilion angle was greater for patients in their 40s than those in their 20s (P <0.05), whereas the lower lip vermilion angle was only lower for patients with Class II malocclusion (P <0.05). CONCLUSIONS: Middle-aged adult females (40-49 years) had a lower upper lip height and greater mouth width than those in their 20s, regardless of skeletal malocclusion. However, prominent morphologic aging changes of the lips were noted on the upper lip for skeletal Class III malocclusion and the lower lip for skeletal Class II malocclusion, implying that the underlying skeletal features (or malocclusion) may influence 3D aging changes of the lips.

Skeletal and dentoalveolar effects of miniscrew-assisted rapid palatal expansion based on the length of the miniscrew: a randomized clinical trial.

OBJECTIVES: To compare skeletal and dentoalveolar changes of miniscrew-assisted rapid palatal expansion (MARPE) according to the length of the miniscrews. MATERIALS AND METHODS: This two-arm parallel-randomized controlled trial included 32 adult patients aged 19-35 years who received orthodontic treatment with MARPE. Patients were allocated to two groups, group long (L) and short (S), through block randomization according to the length of the miniscrews installed in MARPE. Cone-beam computed tomography was performed before expansion and after removal of the MARPE; superimposition of the images was conducted. The primary outcome included the amount of bone expansion and the change in the inclination of the anchorage teeth. The secondary outcome included the success rate of midpalatal suture opening and stability of the miniscrews. Blinding was performed during outcome assessment. RESULTS: The final sample comprised 31 patients. There was no significant difference in patient characteristics between group L (n = 16) and group S (n = 15). The change in the width of the processus zygomaticus (P = .010) and ectocanine (P = .001) was significantly higher in group L. A significantly higher success rate of the posterior miniscrews was seen in group L (P = .024). There was no statistically significant difference in the success rate of suture separation or change in tooth inclination. Notable complications were not reported. CONCLUSIONS: MARPE with longer miniscrews can increase the amount of expansion of the maxillary basal bone and canine alveolar bone. Although it also aided in miniscrew stability, it did not guarantee successful midpalatal suture separation.

Stability of vertical dimension following total arch intrusion.

BACKGROUND: The purpose of this study is to evaluate stability of vertical dimension following total arch intrusion using miniscrews by measuring the change during treatment and relapse amount after more than one year of retention. METHODS: Thirty patients (6 men, 24 women) were included in this study. Lateral cephalographs were taken with conventional radiography at the start of treatment (T0), after treatment (T1), and at least one year after treatment (T2). The evaluation was performed by measuring changes of selected parameters during treatment and the extent of relapse after more than one year. RESULTS: During total arch intrusion treatment (T1-T0), anterior and posterior teeth intruded significantly. The mean vertical distance between the maxillary posterior teeth and palatal plane was reduced by 2.30 mm (P < 0.001). The mean vertical distance between the maxillary anterior teeth and palatal plane was reduced by 2.04 mm (P < 0.001). The anterior facial height was also reduced by 2.70 mm (P < 0.001). During retention period (T2-T1), the vertical distance between the maxillary anterior teeth and the palatal plane significantly increased by 0.92 mm (P < 0.001). The anterior facial height increased by 0.81 mm (P < 0.01). CONCLUSIONS: Anterior facial height significantly decreases after treatment. During retention period, relapse of AFH and maxillary anterior teeth observed. There was no correlation between initial amount of AFH, mandibular plane angle, or SNPog and posttreatment AFH relapse. However, there was a significant correlation between the amount of intrusion of anterior and posterior teeth achieved by the treatment and the extent of relapse.

Cerium oxide nanozymes confer a cytoprotective and bio-friendly surface micro-environment to methacrylate based oro-facial prostheses.

Poly-(methyl methacrylate) (PMMA) is the preferred biomaterial for orofacial prostheses used for the rehabilitation of naso-palatal defects. However, conventional PMMA has limitations determined by the complexity of the local microbiota and the friability of oral mucosa adjacent to these defects. Our purpose was to develop a new type of PMMA, i-PMMA, with good biocompatibility and better biological effects such as higher resistance to microbial adhesion of multiple species and enhanced antioxidant effect. The addition of cerium oxide nanoparticles to PMMA using a mesoporous nano-silica carrier and polybetaine conditioning, resulted in an increased release of cerium ions and enzyme mimetic activity, without tangible loss of mechanical properties. Ex vivo experiments confirmed these observations. In stressed human gingival fibroblasts, i-PMMA reduced the levels of reactive oxygen species and increased the expression of homeostasis-related proteins (PPARg, ATG5, LCI/III). Furthermore, i-PMMA increased the levels of expression of superoxide dismutase and mitogen-activated protein kinases (ERK and Akt), and cellular migration. Lastly, we demonstrated the biosafety of i-PMMA using two in vivo models: skin sensitization assay and oral mucosa irritation test, respectively. Therefore, i-PMMA offers a cytoprotective interface that prevents microbial adhesion and attenuates oxidative stress, thus supporting physiological recovery of the oral mucosa.

Reorientation methodology for reproducible head posture in serial cone beam computed tomography images.

Low dose and accessibility have increased the application of cone beam computed tomography (CBCT). Often serial images are captured for patients to diagnose and plan treatment in the craniofacial region. However, CBCT images are highly variable and lack harmonious reproduction, especially in the head's orientation. Though user-defined orientation methods have been suggested, the reproducibility remains controversial. Here, we propose a landmark-free reorientation methodology based on principal component analysis (PCA) for harmonious orientation of serially captured CBCTs. We analyzed three serial CBCT scans collected for 29 individuals who underwent orthognathic surgery. We first defined a region of interest with the proposed protocol by combining 2D rendering and 3D convex hull method, and identified an intermediary arrangement point. PCA identified the y-axis (anterioposterior) followed by the secondary x-axis (transverse). Finally, by defining the perpendicular z-axis, a new global orientation was assigned. The goodness of alignment (Hausdorff distance) showed a marked improvement (> 50%). Furthermore, we clustered cases based on clinical asymmetry and validated that the protocol was unaffected by the severity of the skeletal deformity. Therefore, it could be suggested that integrating the proposed algorithm as the preliminary step in CBCT evaluation will address a fundamental step towards harmonizing the craniofacial imaging records.

Multistability and hysteresis in states of oral microbiota: Is it impacting the dental clinical cohort studies?

INTRODUCTION: Microbiome from a "healthy cohort" is used as a reference for comparison to cases and intervention. However, the studies with cohort-based clinical research have not sufficiently accounted for the multistability in oral microbial community. The screening is limited to phenotypic features with marked variations in microbial genomic markers. Herein, we aimed to assess the stability of the oral microbiome across time from an intervention-free "healthy" cohort. METHODS: We obtained 33 supragingival samples of 11 healthy participants from the biobank. For each participant, we processed one sample as baseline (T0) and two samples spaced at 1-month (T1) and 3-month (T2) intervals for 16S ribosomal RNA gene sequencing analysis. RESULTS: We observed that taxonomic profiling had a similar pattern of dominant genera, namely, Rothia, Prevotella, and Hemophilus, at all time points. Shannon diversity revealed a significant increase from T0 (p < .05). Bray Curtis dissimilarity was significant (R = -.02, p < .01) within the cohort at each time point. Community stability had negative correlation to synchrony (r = -.739; p = .009) and variance (r = -.605; p = .048) of the species. Clustering revealed marked differences in the grouping patterns between the three time points. For all time points, the clusters presented a substantially dissimilar set of differentially abundant taxonomic and functional biomarkers. CONCLUSION: Our observations indicate towards the presence of multistable states within the oral microbiome in an intervention-free healthy cohort. For a conclusive and meaningful long-term reference, dental clinical research should account for multistability in the personalized therapy approach to improve the identification and classification of reliable markers.

Changes in masticatory performance during the retention period following 4-premolar extraction and non-extraction orthodontic treatment.

OBJECTIVES: To evaluate changes in masticatory performance (MP) during the retention period after extraction and non-extraction treatment and compare it with MP in individuals with normal occlusion. MATERIALS AND METHODS: Adult patients who had completed orthodontic fixed appliance treatment comprised the extraction and non-extraction treatment groups, and those with normal occlusion comprised the control group. Their mixing ability (MA), maximum bite force (MBF), and occlusal contact area (OCA) were recorded immediately after the fixed appliance was removed and at 1 month, 6 months, and 1 year post-treatment. The MA was measured via the two-color chewing gum MA test using ViewGum software, and the MBF and OCA were measured using Dental Prescale II system. RESULTS: MA immediately after orthodontic treatment was lower than that in the normal group but showed a time-dependent gradual increase during a 1-year retention period (P < 0.01). The MA at 1 month post-treatment was not significantly different between the three groups (P > 0.05). The MA revealed a significant correlation with the MBF and OCA (P < 0.01). CONCLUSIONS: The MP immediately after orthodontic treatment was lower than that in the normal group but increased gradually, with levels comparable to those of the normal occlusion group at 1 month post-treatment. Further, extraction did not affect the recovery of the MP after orthodontic treatment. CLINICAL RELEVANCE: No other study has evaluated the changes in MP during the retention period after orthodontic treatment. The findings show that compared with MBF and OCA, the patients' MP improved faster to levels found in normal occlusion.

Changes in mechanical and bacterial properties of denture base resin following nanoceria incorporation with and without SBA-15 carriers.

Poly (methyl methacrylate) (PMMA) is a commonly used material for the fabrication of biomedical appliances. Although PMMA has several advantages, it is susceptible to microbial insults with practical use. Therefore, different bioactive nanomaterials, such as nanoceria (CeN), have been proposed to enhance the properties of PMMA. In this study, we investigated the effect of the incorporation of CeN into PMMA with and without the use of mesoporous silica nanoparticle (SBA-15) carriers. The unmodified PMMA specimens (control, CTRL) were compared to groups containing SBA-15, CeN, and the synthesized SBA-15 impregnated with CeN (SBA-15@CeN) at different loading percentages. The mechanical and physical properties of the different SBA-15@CeN groups and their effects on cell viability were investigated, and the optimal CeN concentration was identified accordingly. Our results revealed that flexural strength was significantly (P < 0.01) reduced in the SBA-15@CeN3× group (containing 3-fold the CeN wt. %). Although the surface microhardness increased with the increase in the wt. % of SBA-15@CeN, cell viability was significantly reduced (P < 0.001). The SBA-15@CeN1× group had the optimal concentration and displayed significant resistance to single-and multispecies microbial colonization. Finally, the enzymatic activity of CeN was significantly high in the SBA-15@CeN1× group. The proinflammatory markers (IL-6, IL-1ß, TNF-α, CD80, and CD86) showed a significant (P < 0.001) multifold reduction in lipopolysaccharide-induced RAW cells treated with a 5-day eluate of the SBA-15@CeN1× group. These results indicate that the addition of SBA-15@CeN at 1.5 wt % improves the biological response of PMMA without compromising its mechanical properties.

Polybetaine-enhanced hybrid ionomer cement shows improved total biological effect with bacterial resistance and cellular stimulation.

Hybrid ionomer cements (HICs) are aesthetic polyelectrolyte cements that have been modified with a resin. The setting of HICs occurs by both monomer polymerization and an acid-base reaction. In addition, HICs contain a resin, which is substituted for water. Thus, the competition between the setting reactions and reduced water content inherently limits polysalt formation and, consequently the bioactive interactions. In this study, we explored the effects of polybetaine zwitterionic derivatives (mZMs) on the augmentation of the bioactive response of HICs. The polybetaines were homogenized into an HIC in different proportions (α, ß, and γ) at 3% w/v. Following basic characterization, the bioactive response of human dental pulp stem cells (hDPSCs) was evaluated. The augmented release of the principal constituent ions (strontium, silica, and fluoride) from the HIC was observed with the addition of the mZMs. Modification with α-mZM elicited the most favorable bioactive response, namely, increased ion elution, in vitro calcium phosphate precipitation, and excellent biofouling resistance, which deterred the growth of the bridging species of Veillonella. Moreover, α-mZM resulted in a significant increase in the hDPSC response, as confirmed by a significant increase (p < 0.05) in alizarin red staining. The results of mRNA expression tests, performed using periodically refreshed media, showed increased and early peak expression levels for RUNX2, OCN, and OPN in the case of α-mZM. Based on the results of the in vitro experiments, it can be concluded that modification of HICs with polybetaine α-mZM can augment the overall biological response.

Evaluation of miniscrew-assisted rapid palatal expansion success by comparing width of circummaxillary sutures before expansion in adult male patients.

OBJECTIVES: To investigate the relationship between circummaxillary sutures and miniscrew-assisted rapid palatal expansion (MARPE) success in adult male patients and to evaluate the correlation between the width of the sutures and the maxilla expansion ratio. MATERIALS AND METHODS: This retrospective study comprised 40 adult male patients treated with MARPE divided into a separation group (N = 20, mean age, 21.9 years) consisting of subjects with midpalatal suture opening and a nonseparation group (N = 20, mean age, 21.7 years) consisting of subjects with no midpalatal suture opening. Cone-beam computed tomography images were obtained before MARPE expansion for both groups and after expansion for the separation group. Vertical and horizontal skeletal relationships, palate length, and widths of 10 circummaxillary sutures before expansion were compared. The correlation between maxilla expansion ratio (jackscrew expansion to maxillary expansion ratio) and circummaxillary suture widths was also analyzed in the separation group. RESULTS: There were no significant differences in age, vertical and horizontal skeletal relationships, and palate length between the two groups. Zygomaticomaxillary, pterygomaxillary, midpalatal, and transverse palatine sutures showed significantly greater width in the separation group (P < .05). The zygomaticomaxillary suture showed the greatest difference (Δ = 0.36 mm) between the groups. The zygomaticomaxillary and pterygomaxillary sutures showed significant positive correlation with the maxilla expansion ratio (P < .01). CONCLUSIONS: In adult male patients, greater circummaxillary suture widths before MARPE expansion, especially zygomaticomaxillary and pterygomaxillary sutures, resulted in a better chance of successful suture separation and more maxillary expansion.

Accuracy and stability of computer-aided customized lingual fixed retainer: a pilot study.

BACKGROUND: With advances in digital technology, new types of lingual fixed retainers are being developed. However, there are few studies that quantitatively evaluate the accuracy and stability of lingual fixed retainers. The aim of this study was to assess the accuracy and stability of two types of computer-aided customized lingual fixed retainers and a conventional lingual fixed retainer. METHODS: A total of 10 maxillary and 10 mandibular duplicated dental models were selected, and then, three types of retainers were fabricated on the canine-to-canine area for each model. To evaluate accuracy, wire clearance at interproximal area (WCI) was measured using superimposition analysis. Initial flatness deformation was also measured for vertical distortion of retainers. Lateral width, anteroposterior length, and flatness deformation were measured at three-time points for stability assessment. Thermocycling was used to induce 6 months of time flow. RESULTS: The custom-bent group showed significantly higher WCI than the custom-cut and manual groups in the maxillary arch (P = 0.002). The custom-cut group showed significantly less flatness deformation, which was followed by the custom-bent and manual groups in both the maxillary and mandibular arch (P < 0.001). There was no significant difference in stability between the three retainer groups during 5100 cycles of thermocycling (corresponding to 6-month period). CONCLUSIONS: Since there was no difference in stability between the three groups, it is recommended to use custom-cut type retainers in light of accuracy. However, accuracy and stability are not the only factors to consider when selecting type of retainers. Because each retainer has advantages and disadvantages, the type of retainers should be decided in consideration of the clinical environment.