Search

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 (

Polyalkenoate cement (PAC) is a promising material for regenerative hard tissue therapy. The ionically rich glass component of PAC encourages bioactive interaction via. the release of essential ions. However, PAC bioactivity is restricted owing to (i) structurally inherent cationic network formers and (ii) surface bacterial biofilm formation. These two factors cause a deficiency in ion release, further complicated by secondary infections and premature therapeutic failure. Here, a multivalent zwitterionic network modifier (mZM) is presented for upregulation of ionic exchange and bioactivity enhancement. By introducing a non-zero charged mZM into PACs, an increase in the proportion of non-bridging oxygen occurs. The network modification promotes ion channel formation, causing a multiple-fold increase in ion release and surface deposition of hydroxy-carbonate apatite (ca. 74%). Experiments ex vivo and animal models also demonstrate the efficient remineralization ability of the mZM. Furthermore, divalent cationic interaction results in bacterial biofilm reduction (ca. 68%) while also influencing a shift in the biofilm species composition, which favors commensal growth. Therefore, PAC modification with mZM offers a promising solution for upregulation of bioactivity, even aiding in customization by targeting site-specific regenerative therapy in future applications.

Background Phosphate-based glass (PBG) is an attractive bioactive material for promoting the cellular regenerative response. PBG consists of glass network which contains phosphate as the main component and can be substituted into various therapeutic ions. Strontium (Sr) can stimulate osteogenic activity and inhibit the pro-inflammatory response. However, there are limited studies on the characterization and biological performance Sr-substituted PBG (PSr). In this study, PSr was characterized and its of immuno-osteogenic response potential was investigated for substituting Ca with Sr. Considering a priority for cellular activity, we compared the optimized PSr against the benchmark 45S5 bioactive glass (BG) for its effect on cellular bioactive response and regenerative hard tissue. Methods PSr groups were fabricated by a melt-quenching method; subsequently, they were characterized and their biological performance was investigated for the preference of PSr. Considering the clinically used BG as the benchmark, PSr was evaluated based on the cytotoxicity assay, osteogenic activity, pro-inflammatory response, and implantation of calvaria bone defect. Results PSr groups exhibited a glass structure and phosphate network similar to that of PBG. However, the results of ion release analysis showed that PSr6 was stable in accordance with Ca/P, Ca/Sr, and P/Sr ratios. Based on these results, the cellular response of PSr6 was the highest, which increased for the early osteogenic marker and inhibited the inflammatory response. Compared to the clinically used BG as the benchmark, PSr6 promoted osteogenic activity and suppressed inflammatory response. The results of in vivo study indicated that the new bone formation in the PSr6 was similar to that in benchmark BG. However, the limitation of this study was the four weeks of implantation. However, the results of our study suggest that PSr6 is promising for enhancing the immuno-osteogenic response and regenerating hard tissue with the optimized glass structure having Ca/Sr ratio of 2:1. Conclusions The developed PSr6 demonstrated stable physical properties, favorable cytocompatibility, and immune-osteogenic response. Compared with benchmark BG, PSr6 exhibited enhanced immuno-osteogenic response and regeneration of new bone and connective tissues. Therefore, PSr6 is a potential bone grafting material for regenerative hard tissue.

The first important step in orthodontic treatment is an accurate diagnosis and precise treatment planning to correct the malocclusion. This process entails a proper examination and understanding of the nature of malocclusion and the anomaly of the underlying structures. The emergence of three dimensional (3D) technology has transformed the field of orthodontics. The present article aims to take into account some of the applications of 3D technology in the field of orthodontics.

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.

ObjectivesThe use of 16S ribosomal RNA gene sequencing analyses has rapidly increased in clinical oral studies. However, cohort-based clinical research has not sufficiently accounted for the periodic stability in oral microbiota. Herein, we aimed to assess the stability of the oral microbiome across time from an intervention-free “healthy” cohort. Materials and MethodsWe 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 monthly (T1) and quarterly (T2) intervals for 16S ribosomal RNA gene sequencing analysis. ResultsWe 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 (pp

The orientation of the occlusal plane (OP) influences the functional and esthetic balance of the face. We report on two patients for which the careful consideration of OP angulation from diagnosis to treatment planning aided in achieving a superior esthetic correction and improved stability. In both surgical patients, adequate presurgical control of the OP facilitated the surgical correction with a rotation of the OP. The results showed a better esthetic outcome and improved orientation of the musculoskeletal relation. Therefore, in severe mandibular prognathism or retrognathism, adequate planning of the OP orientation is of high significance.

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@CeN

Poly(methyl methacrylate) (PMMA)-based denture base resins easily develop oral bacterial and fungal biofilms, which may constitute a significant health risk. Conventional bacterial-resistant additives and coatings often cause undesirable changes in the resin. Reduced bacterial resistance over time in the harsh oral environment is a major challenge in resin development. Poly(2-methoxyethyl acrylate) (PMEA) has anti-fouling properties; however, due to the oily/rubbery state of this polymer, and its surface aggregation tendency in a resin mixture, its direct use as a resin additive is limited. This study aimed to optimize the use of PMEA in dental resins. Acrylic resins containing a series of PMEA polymers with various molecular weights (MWs) at different concentrations were prepared, and the mechanical properties, surface gloss, direct transmittance, and cytotoxicity were evaluated, along with the distribution of PMEA in the resin. Resins with low-MW PMEA (2000 g mol

The main clinical and radiological defect in cleft maxilla is localised at the region of nasomaxillary complex and thereby the increased focus on maxillary interventional correction. During the period of development, the affected individual undergoes a series of periodic treatment approaches aimed towards normalisation of the function and aesthetics. However, such interventional procedures can have otherwise effects on the restriction of growth. Surgical and facial orthopaedic interventions can cause protrusion of the premaxilla. This influences the depth and height of the upper jaw and thus the total height causing clockwise rotation of the face. Similarly, the depth of the posterior maxilla is found to be reduced in CLP cases. The advancement of the anterior maxilla with callus distraction for correction of the cleft maxilla was first reported by KraKasis and Hadjipetrou in 2004. The technique has been used since then with variable success and less predictability. The present table clinic is targeted to showcase the key features of various stages critical in planning the anterior maxillary distraction in adult maxillary hypoplasia cases. The requirement of precision in planning and treatment is high in such cases to minimize the adverse effects. The novel methodology discussed here is the combination of CBCT, face bow transfer and stereolithography for surgical planning and simulation. With the use of CBCT diagnostic capacity is enhanced, enabling visualisation of the defect. It also helps to simulate surgical procedure virtually and/or with the application of stereolithography. Use of the face bow facilitates biomechanical planning. The registration of the maxillomandibular relation to the cranial base serves as a guide to position the distractor. This is a critical step, as it dictates the direction of the distraction force vectors. Precise orientation and planning enable predictable movement of the anterior maxilla and control the extent of anterior open bite opening, in most cases. This contrasts with the overbite created with counter clockwise jaw rotation, reducing the post distraction orthodontic management. This table clinic presentation also draws home the key points in identifying and mitigating the potential complications during and after the distraction. The use of the present methodology enables a predictive treatment outcome for the cases with minimal complications associated with distraction with a marked reduction in the magnitude of callus molding. Therefore, with the application of this novel clinical paradigm for AMD, a predictable result can be achieved, which helps in the reduction of the treatment time and gives a stable outcome

The properties of underlying substrates influence the quality of an intraoral scan, but few studies have compared the outcomes using common restorative materials. In this study, we aimed to compare the accuracy of digital and conventional impressions recorded for four different dental materials as the substrates. Experimental crowns were produced with a metallic surface (gold or cobalt-chromium alloy (Co-Cr)) or without a metallic surface (zirconia or PMMA (polymethyl methacrylate)). A conventional impression was made in the conventional group (CON group), and gypsum models were subsequently scanned with a tabletop scanner. An intraoral scanner was used to scan the crowns either after applying a powder spray to reduce the surface reflectivity (IOS-P group) or without the powder spray (IOS group). The scans were assessed in three dimensions for precision and trueness. The accuracy did not differ between the CON and IOS groups for the non-metallic crowns. However, it was statistically different for the Co-Cr metallic crown, reducing trueness observed between groups as CON &gt, IOS &gt, IOS-P. The study evidences the differences in outer surface accuracy observed with a change in the substrate material to be imaged using an oral scanner and with the impression method. These findings suggest that the restoration material present in the oral cavity should be considered when selecting an impression-taking method.

The plane formed by the intersection of bilateral porions (PoR and PoL) and left orbitale (OrL) is conventionally defined as the Frankfort horizontal (FH) plane. We aim to test the influence of the FH plane definition on a 3D cephalometric assessment. We selected 38 adult patients (20 males, 18 females, average age: 22.87 &plusmn, 5.17 years) without any gross asymmetry from retrospective records and traced and analyzed their cone-beam computed tomographic images. The findings were categorized into the following four groups: FH1: conventional, FH2: PoR, PoL, right orbitale (OrR), FH3: OrR, OrL, PoL, FH4: OrR, OrL, PoR. The average menton (Me) deviation from the MSP was statistically significant for the FH1 group (0.56 &plusmn, 0.27 mm, p &lt, 0.001), compared to the FH3 (1.37 &plusmn, 1.23 mm) and FH4 (1.33 &plusmn, 1.16 mm) groups. The spatial orientation level (SOL) of the FH plane showed a marked difference (p &lt, 0.05) between the FH2 (0.602&deg, &plusmn, 0.503&deg, ) and FH4 (0.944&deg, 0.778&deg, ) groups. The SOL of the MSP was comparatively small (p &lt, 0.001) for FH2 (0.015&deg, 0.023&deg, ) in comparison to both FH 3 (0.644&deg, 0.546&deg, ) and FH 4 (0.627&deg, 0.516&deg, ). Therefore, the FH plane definition can significantly influence the interpretation of cephalometric findings. Future studies should focus on standardization to improve the reliability and reproducibility of 3D cephalometry.

Objective: To investigate the cephalometric changes following anterior repositioning of the mandible for predicting the treatment effects in Class II adolescent patients. Study Design: Lateral cephalograms of 28 patients (ANB > 4°) were taken in centric occlusion (CO) and edge-to-edge bite (EtoE) before orthodontic treatment. The patients were classified into two groups according to their mandibular plane angle [MPA; low MPA (LMPA) ≤ 28° and high MPA (HMPA) > 28°]. Cephalometric changes of hard and soft tissues were measured and analyzed with an x-y cranial base coordinate system. Results: For CO to EtoE, there were no significant cephalometric changes between HMPA and LMPA, but the horizontal ratio of soft to hard tissue pogonion (H-Pog′/H-Pog) change was significantly greater with LMPA than with HMPA while the vertical ratio (V-Pog′/V-Pog) showed vice versa. For CO to EtoE, MPA showed significant correlations with H-Pog′/H-Pog and V-Pog′/V-Pog. Y-axis angle, V-Pog′/V-Pog and H-Pog′/H-Pog can be used as good tools to discriminate between HMPA and LMPA. Conclusion: Cephalometric findings for CO to EtoE may be useful in predicting the vertical and horizontal changes of hard and soft tissues with the treatment of growing adolescents having various vertical skeletal patterns of Class II malocclusion.

Since pits and fissures are the areas most commonly affected by caries due to their structural irregularity, bioactive resin-based sealant (RBS) may contribute to the prevention of secondary caries. This study aims to investigate the mechanical, physical, ion-release, enamel remineralisation, and antibacterial capabilities of the novel RBS with bioactive glass (BAG) and 2-methacryloyloxyethyl phosphorylcholine (MPC). For the synthesis, 12.5 wt% BAG and 3 wt% MPC were incorporated into RBS. The contact angle, flexural strength, water sorption, solubility, and viscosity were investigated. The release of multiple ions relating to enamel remineralisation was investigated. Further, the attachments of bovine serum albumin, brain heart infusion broth, and Streptococcus mutans on RBS were studied. Finally, the thickness and biomass of a human saliva-derived microsm biofilm model were analysed before aging, with static immersion aging and with thermocycling aging. In comparison to commercial RBS, BAG+MPC increased the wettability, water sorption, solubility, viscosity, and release of multiple ions, while the flexural strength did not significantly differ. Furthermore, RBS with MPC and BAG+MPC significantly reduced protein and bacteria adhesion and suppressed multi-species biofilm attachment regardless of the existence of aging and its type. The novel RBS has great potential to facilitate enamel remineralisation and suppress biofilm adhesion, which could prevent secondary dental caries.

Prevention of dental caries is a key research area, and improvement of the pit and fissure sealants used for caries prevention has been of particular interest. This report describes results of incorporating a zwitterion, sulfobetaine methacrylate (SB), into photo-polymerized resin-based sealants to enhance resistance to cariogenic bacteria and protein adhesion. Varying amounts (1.5&ndash, 5 wt%) of SB were incorporated into a resin-based sealant, and the flexural strength, wettability, depth of cure, protein adhesion, bacterial viability, and cell cytotoxicity of the resultant sealants were evaluated. The flexural strength decreased with the increasing SB content, but this decrease was statistically significant only for sealants containing &ge, 3 wt% SB. Incorporating a zwitterion led to a significant reduction in the water contact angle and protein adhesion. The colony-forming unit count showed a significant reduction in the bacterial viability of S. mutans, which was confirmed with microscopic imaging. Moreover, cell cytotoxicity analysis of SB-modified sealants using an L929 fibroblast showed a cytotoxicity comparable to that of an unmodified control, suggesting no adverse effects on the cellular metabolism upon SB introduction. Hence, we conclude that the addition of 1.5&ndash, 3 wt% SB can significantly enhance the inherent ability of sealants to resist S. mutans adhesion and prevent dental caries.

It is essential for 3D-printed intra-oral appliances to be able to withstand the mechanical and microbial insult existent in the harsh environment of the oral cavity. Poly(methyl methacrylate) (PMMA)-based appliances are widely used in dentistry. Hence, the present study aimed to evaluate the role of nanodiamonds (NDs) as fillers to enhance the resistance to friction and wear. Using a solution-based mixing technique, 0.1 wt% ND was incorporated into the PMMA, and specimens were 3D-printed for tribological and bacterial analysis. The control specimens without ND fillers were tested against specimens with both amine-functionalized NDs (A-ND) and pure non-functionalized NDs (ND). The surface hardness test revealed a statistically significant increase in the Vickers micro-hardness (p 0.001) in the nanocomposite groups. There was a significant reduction in the coefficient of friction (COF) (p 0.01) in both the ND and A-ND nanocomposites compared to the stainless steel (SS) counter surfaces. However, for titanium (Ti)-based specimens, the COF of the control group was similar to that of A-ND but lower than that of ND. The wear resistance evaluation revealed that both the ND and A-ND groups displayed enhanced resistance to surface loss in comparison to the controls for both SS and Ti counter-surfaces (p 0.001). Furthermore, both A-ND and ND exhibited significantly enhanced resistance to the formation of Streptococcus mutans biofilms after 48 h (p 0.01) compared to the control group. Hence, we concluded that the addition of 0.1 wt% ND in the PMMA-based resin for 3D printing resulted in significant improvement in properties such as COF, wear resistance, and resistance to S. mutans, without any notable impact associated with the functionalization of the NDs.

Anchorage in orthodontics is a decisive factor in progress and outcome of a case. With the advent of mini-implants, great advances have been achieved in terms of absolute anchorage. The following article compares the use of stainless steel and titanium implants in a split mouth, controlled clinical study, having direct in vivo comparison. 10 patients were selected for the same and carefully evaluated. The mini-implants were placed in the buccal mucosa, under local anaesthesia, after radiographic safe zone selection. The loading protocol was standardised with low immediate load, followed by incremental load up to 150g. For the study, the cases planned with en-masse retraction of the anteriors into the premolar space were selected for the uniformity in mechanics. The results are discussed with comparative analysis between the two materials and their success rate individually and in relation to upper and lower jaw respectively. In results, a significant success rate has been found with use of titanium implants, with higher implant failure in upper jaw compared to lower jaw.

During fixed orthodontic treatment, maintenance of a good gingival health is challenging. This necessitates use of prophylactic measures, such as use of fluoridated tooth pastes and application of varnish. Use of chlorhexidine (CHX) varnish, is believed to reduce the bacterial count and have a longer duration of action, by virtue of sustained release. Therefore, the aim of the present study is to assess the clinical effects of chlorhexidine varnish (Cervitec plus) on plaque accumulation and gingival health during multibracket orthodontic treatment. 26 patients were selected for the prospective clinical study. The study design was a split-mouth pattern, with contralateral sides serving as control. Application of CHX varnish was done twice, in a 12 week interval. Plaque and gingival indices were recorded before the application and at a 4 week interval. Using students T-test, comparative analysis between the control and CHX group was done. A significant reduction, in CHX group, in the gingival and plaque scores at 3 and 6 months after the first visit as compared to the baseline value. The control group showed an increase in the gingival and plaque scores at 0-3 and 0- 6 months interval. There was no significant reduction in gingival scores between 3 and 6 months in test (CHX) group. Chlorhexidine varnish brought about both significant reduction in gingival and plaque index scores over a period of 6 months when compared to the control. Second application of varnish did not bring about significant reduction in gingival and plaque scores when compared to control group.

The application of 3D imaging is at its cusp in craniofacial diagnosis and treatment planning. However, most applications are limited to simple subjective superimposition-based analysis. As the diagnostic accuracy dictates the precision in operability, we propose a novel method that enables objective clinical decision making for patients with mandibular asymmetry. We analyzed cone-beam computed tomography (CBCT) scans of 34 patients who underwent surgical correction for mandibular asymmetry using a high-throughput computing algorithm. Radiomic segmentation of quantitative features of surface and volume followed by exploration resulted in identification of a computed modified absolute mandibular midsagittal plane (cmAMP). Tomographic similarity scan (ToSS) curves were generated via bilateral equidistant scanning in an antero-posterior direction with cmAMP as the reference. ToSS comprised of a comprehensive similarity index (SI) score curve and a segment-wise volume curve. The SI score was computed using the Sørensen-Dice similarity coefficient ranging from 0 to 1. The volumetric analysis was represented as the non-overlapping volume (NOV) and overlapping volume (OV) for each segment, with two segmentation lines, at the mental foramen anteriorly and the intraoral vertical ramus osteotomy region posteriorly. Statistical analysis showed strong negative correlation between the NOV and SI scores for the anterior, middle, and total mandible (P 0.001). Additionally, a significant correlation was observed between the change in the SI scores for anterior (P = 0.044) and middle segments (P 0.001) to the total mandible when comparing the data before and after the surgery. This work demonstrated the potential of incorporating ToSS curves in surgical simulation software to improve precision in the clinical decision-making process.

Herein we evaluate the effect of nanodiamond (ND) incorporation on the mechanical properties of poly(methyl methacrylate) (PMMA) nanocomposite. Three quantities of ND (0.1, 0.3, and 0.5 wt.%) were tested against the control and zirconium oxide nanoparticles (ZrO). Flexural strength and elastic modulus were measured using a three-point bending test, surface hardness was evaluated using the Vickers hardness test, and surface roughness was evaluated using atomic force microscopy (AFM), while fungal adhesion and viability were studied using Candida albicans. Samples were also analyzed for biofilm thickness and biomass in a saliva-derived biofilm model. All groups of ND-PMMA nanocomposites had significantly greater mean flexural strengths and statistically improved elastic modulus, compared to the control and ZrO groups (P &lt, 0.001). The Vickers hardness values significantly increased compared to the control group (P &lt, 0.001) with 0.3% and 0.5% ND. ND addition also gave significant reduction in fungal adhesion and viability (P &lt, 0.001) compared to the control group. Finally, salivary biofilm formation was markedly reduced compared to the ZrO group. Hence, the incorporation of 0.1&ndash, 0.5 wt.% ND with auto- polymerized PMMA resin significantly improved the flexural strength, elastic modulus, and surface hardness, and provided considerable fungal resistance.

Objective The aim of this retrospective study was to evaluate the pre- and postsurgical bone densities at alveolar and extra-alveolar sites following twojaw orthognathic surgery. Methods The sample consisted of 10 patients (mean age, 23.2 years; range, 18.0-27.8 years; 8 males, 2 females) who underwent two-jaw orthognathic surgery. A three-dimensional imaging program (Invivo 5) was used with multidetector computed tomography images taken preand postoperatively (obtained 32.3 ± 6.0 days before surgery and 5.8 ± 2.6 days after surgery, respectively) for the measurement of bone densities at the following sites: (1) alveolar bone in the maxilla and mandible, (2) extra-alveolar sites, such as the top of the head, menton (Me), condyle, and the fourth cervical vertebrae (C4). Results When pre- and postsurgical bone densities were compared, an overall tendency of decrease in bone density was noted. Statistically significant reductions were observed in the densities of cancellous bone at several areas of the maxillary alveolar bone; cortical and cancellous bone in most areas of the mandibular alveolar bone; cortical bone in Me; and cancellous bone in C4. There was no statistically significant difference in bone density in relation to the depth of the alveolar bone. In a comparison of the bone densities between groups with and without genioplasty, there was almost no statistically significant difference. Conclusions Accelerated tooth movement following orthognathic surgery may be confirmed with reduced bone density. In addition, this study could offer insights into bone metabolism changes following orthognathic surgery, providing direction for further investigations in this field.

Poly(methyl methacralyate) (PMMA) has long been used in dentistry as a base polymer for dentures, and it is recently being used for the 3D printing of dental materials. Despite its many advantages, its susceptibility to microbial colonization remains to be overcome. In this study, the interface between 3D-printed PMMA specimens and oral salivary biofilm was studied following the addition of zwitterionic materials, 2-methacryloyloxyethyl phosphorylcholine (MPC) or sulfobetaine methacrylate (SB). A significant reduction in bacterial and biofilm adhesions was observed following the addition of MPC or SB, owing to their protein-repellent properties, and there were no significant differences between the two test materials. Although the mechanical properties of the tested materials were degraded, the statistical value of the reduction was minimal and all the properties fulfilled the requirements set by the International Standard, ISO 20795-2. Additionally, both the test materials maintained their resistance to biofilm when subjected to hydrothermal fatigue, with no further deterioration of the mechanical properties. Thus, novel 3D-printable PMMA incorporated with MPC or SB shows durable oral salivary biofilm resistance with maintenance of the physical and mechanical properties.

The increasing demand for orthodontic treatment over recent years has led to a growing need for the retrieval and reuse of titanium-based miniscrews to reduce the cost of treatment, especially in patients with early treatment failure due to insufficient primary stability. This in vitro study aimed to evaluate differences in the primary stability between initially inserted and re-inserted miniscrews within different cortical bone densities. Artificial bone was used to simulate cortical bone of different densities, namely 20, 30, 40, and 50 pound per cubic foot (pcf), where primary stability was evaluated based on maximum insertion torque (MIT), maximum removal torque (MRT), horizontal resistance, and micromotion. Scanning electron microscopy was used to evaluate morphological changes in the retrieved miniscrews. The MIT, MRT, horizontal resistance, and micromotion was better in samples with higher cortical bone density, thereby indicating better primary stability (P &lt, 0.05). Furthermore, a significant reduction of MIT, MRT, and horizontal resistance was observed during re-insertion compared with the initial insertion, especially in the higher density cortical bone groups. However, there was no significant change in micromotion. While higher cortical bone density led to better primary stability, it also caused more abrasion to the miniscrews, thereby decreasing the primary stability during re-insertion.

The creation of clinically patient-specific 3D-printed biomedical appliances that can withstand the physical stresses of the complex biological environment is an important objective. To that end, this study aimed to evaluate the efficacy of aminated nanodiamonds (A-NDs) as nanofillers in biological-grade acrylate-based 3D-printed materials. Solution-based mixing was used to incorporate 0.1 wt% purified nanodiamond (NDs) and A-NDs into UV-polymerized poly(methyl methacrylate) (PMMA). The ND and A-ND nanocomposites showed significantly lower water contact angles (p &lt, 0.001) and solubilities (p &lt, 0.05) compared to those of the control. Both nanocomposites showed markedly improved mechanical properties, with the A-ND-containing nanocomposite showing a statistically significant increase in the flexural strength (p &lt, 0.001), elastic modulus (p &lt, 0.01), and impact strength (p &lt, 0.001) compared to the control and ND-containing groups. The Vickers hardness and wear-resistance values of the A-ND-incorporated material were significantly higher (p &lt, 0.001) than those of the control and were comparable to the values observed for the ND-containing group. In addition, trueness analysis was used to verify that 3D-printed orthodontic brackets prepared with the A-ND- and ND-nanocomposites exhibited no significant differences in accuracy. Hence, we conclude that the successful incorporation of 0.1 wt% A-ND in UV-polymerized PMMA resin significantly improves the mechanical properties of the resin for the additive manufacturing of precisive 3D-printed biomedical appliances.

The goal of orthodontic treatment is to achieve a stable, functional result with enhanced aesthetics. In the discussed case report, a case with skeletal class III malocclusion is presented with compromised periodontal features and a bilaterally posteriorly edentulous mouth in upper and lower jaw. The case report highlights the corrections achieved and their stability without the support and utilization of the posterior teeth, otherwise deemed essential in the orthodontic treatment planning. The case is treated with orthognathic surgery in upper and lower jaw to improve aesthetic balance of the face. With the use of position screws, the case has been concluded displaying a stable occlusion with improved function. A four-year follow-up and an important note on retention and stability is discussed in the following case report