Three dimensionally printed template with an interproximal isolation design guide consecutive closure of multiple diastema with injectable resin composite.

OBJECTIVE: This article describes a novel 3D-printed template armed with interproximal matrices to isolate interproximal contact areas and guide injectable resin composite for consecutive closure of multiple diastema. CLINICAL CONSIDERATIONS: Among several treatment options proposed for diastema closure, direct resin composite is noninvasive and easy to repair. The "composite injection technique" has been introduced to improve time efficiency and reduce technique sensitivity for clinicians. However, in the case of multiple diastema, the overflow of excess resin materials onto the adjacent teeth during injection poses challenges for recontouring the interproximal anatomy. A 3D-printed template with special-designed gaps at interproximal areas was designed and fabricated based on a virtual diagnostic wax-up. Flowable resin composite was then consecutively injected through the template to close diastemata at multiple adjacent teeth. CONCLUSION: This technique using a 3D-printed template with interproximal isolation design contributed to an efficient and accurate operation for multiple anterior diastema closure. CLINICAL SIGNIFICANCE: Efficient and accurate freehand buildups of composite restoration for multiple diastema are challenging in operative dentistry. The described noninvasive full digital workflow provides a predictable method to accurately recontour the multiple target restorations and reduce the chair-side time and technical sensitivity.

A digital workflow for tooth-supported complete overdentures with a composite resin injection technique to manage the treatment of a child with ectodermal dysplasia.

This clinical report describes a digital workflow for the rehabilitation of an 8-year-old patient diagnosed with ectodermal dysplasia. Based on the patient's digital primary casts, small custom trays and an arch tracer were designed and 3-dimensionally printed. The mandibular custom tray and retention plate with a tracing screw were assembled with tracing plate, forming an individual assembled mini-arch tracer system to record the jaw relationship together with a conventional facebow and a digital articulator. In addition, composite resin injection guides were designed and fabricated to form the predesigned targeted shape of the abutment teeth and provide a buffer. By following this workflow, complete overdentures with good fit, occlusion, and acceptable esthetics were delivered.

Accuracy of the novel digital non-cross-arch surgical guides with integration of tooth undercut retention and screw-bone support for implant placement in mandibular free-end.

BACKGROUND: Large cross-arch free-end surgical guides can obscure the visual field, compromising surgical accuracy due to insufficient stability at the free-end. This in vitro study aims to evaluate the accuracy of novel digital non-cross-arch surgical guides designed for implant placement at the mandibular free-end, incorporating tooth undercut retention and screw-bone support. MATERIALS AND METHODS: A mandibular dental model lacking left molars was utilized to fabricate unilateral (cross-arch) tooth-supported surgical guides (GT I, n = 20). Subsequently, two additional types of surgical guides were fabricated: GT II (covering two teeth, n = 20) and GT III (covering three teeth, n = 20). These novel surgical guides were designed to utilize the undercut of the supporting teeth for retention and enhance stability with screw-bone support at the guide's free-end. Furthermore, 60 identical guiding blocks were assembled on the three types of surgical guides to facilitate the implants' insertion. On a phantom head, 120 implant replicas were placed at the Federal Dentaire Internationale (FDI) teeth positions #36 and #37 on the dental model, employing a combination of surgical guides and guiding blocks. To assess accuracy, planned and placed implant positions were compared using intraoral optical scanning. Discrepancies in angulation and linear deviations, including the coronal/apical 3D deviations, lateral deviation as well as depth deviation, were measured. Statistical analysis was performed using two-way ANOVA and Bonferroni test (α = 0.05). RESULTS: GT I exhibited significantly largest discrepancies, including angular and linear deviations at the crest and apex at every implant site. Especially in depth, at implant site #36, the mean deviation value of GT I (0.27 ± 0.13 mm) was twice as large as GT III (0.13 ± 0.07 mm), and almost twice as large as GT II (0.14 ± 0.08 mm). However, at implant site #37, this deviation increased to almost a five-fold relationship between GT I (0.63 ± 0.12 mm) and II (0.14 ± 0.09 mm), as well as between GT I and III (0.13 ± 0.09 mm). No significant discrepancies existed between the novel surgical guides at either implant site #36 or #37. CONCLUSION: This study provides a practical protocol for enhancing accuracy of implant placement and reducing the size of free-end surgical guides used at mandibular molar sites.

A digital workflow for complete arch rehabilitation with zirconia crowns on restored posterior teeth and a polyetheretherketone framework denture.

A clinical and laboratory workflow for the digital design and fabrication of zirconia crowns and polyetheretherketone removable partial dentures for complete arch rehabilitation is described. The definitive crowns and polyetheretherketone framework can be delivered simultaneously because of the digital design and milling fabrication with retentive areas, guide planes, and rest seats in high-translucency zirconia crowns. The workflow helps simplify clinical and laboratory procedures and reduces patient visits and chairside time.

Technique to restore the midline space of central incisors using a two-in-one template: A clinical report.

Using composite resin restoration of full-coverage crowns to obtain a completely symmetrical esthetic restoration of individual central incisors remains difficult. Freehand direct composite resin restoration is challenging even for highly skilled dentists. This clinical report describes a digital protocol for achieving symmetrical restoration of two central incisors using a custom-designed, two-in-one template.

Clinical decision making of implant guidance methods guided by new classification of surgical area mouth ope-ning.

When selecting implant guidance methods or judging whether the patient can be implanted, many doctors ignore or only use visual inspection to estimate a patient's mouth opening. This phenomenon often leads to failure to complete the implantation due to insufficient mouth opening or the deflection of the implant due to limited angle, resulting in the high incidence of corresponding complications. The main reason is that doctors lack accurate analysis and control of the overall geometric conditions of the intraoral surgical area, and three-dimensional position blocking of surgical instruments occurs during the operation. In the past, mouth opening was defined as the distance between the incisor edges of the upper and lower central incisors when the patient opens his mouth widely, and the implant area could be in any missing tooth position. When it is in the posterior tooth area, the specific measurement scheme of the mouth opening could not be simply equivalent to the previous measurement method in the anterior tooth area. However, how to measure quickly and conveniently the mouth opening of any surgical area to determine whether it could be implanted and meet the needs of the selected guidance method remains unclear. This paper introduces new concepts, establishes new classification and corresponding accurate measurement scheme of implant area, and establishes a decision tree of implant methods guided by the actually measured value. Results provide a quantitative basis for rational formulation and implementation of implant treatment.

Efficient remediation of soils contaminated with petroleum hydrocarbons using sustainable plant-derived surfactants.

Surfactant-enhanced multiphase extraction is recognized as an effective method to remove petroleum related contaminants from soil. Owing to the high biodegradability and low biotoxicity, plant-derived surfactants are considered as promising alternatives to synthetic surfactants. In this study, two plant surfactants were respectively extracted from Sapindus mukorossi (PS-1) and Fructus Gleditsiae sinensis (PS-2). Component analysis and chemical structure characterization indicated that triterpenoid saponins were the main components of both plant surfactants. The removal efficiency of tetradecane by PS-1 and PS-2 was 75.6% and 62.2%, respectively, which was comparable with that by Tween-80. The results were validated by column leaching experiments. The abundant hydroxyl, aldehyde and epoxy groups in the plant surfactants made them readily self-assemble to form micelles via hydrogen bonding and van der Waals interactions, which promoted the solubilization of tetradecane in the liquid phase, particularly at appropriate ionic strength and temperature. Due to the reduced electrostatic attraction by the acidic and ionizable functional groups in the plant surfactants, their sorption capacities (0.15 and 0.24 g1-n Ln·kg-1 for PS-1 and PS-2, respectively) onto the soil were much lower than that of Tween-80, making them much easier to be extracted from contaminated soil. This study would deepen our understanding to improve the performances of plant surfactants in petroleum hydrocarbons-contaminated soil remediation.

In vivo and in vitro evaluation of chitosan-modified bioactive glass paste for wound healing.

In this work, the role of chitosan (CS) in improving the properties of bioactive glass (BG) paste for wound healing was studied. Based on in vitro evaluation, it was found that the addition of CS neutralizes the pH value from 11.0 to 7.5, which did not lead to decreasing the bioactivity of BG paste in vitro. The rheological properties showed that the composite paste had higher bio-adhesion and better affinity with the skin surface than either CS or the BG paste. The antibacterial property evaluation showed that the composite paste had stronger antibacterial activity than either CS or BG paste and promoted the proliferation of HUVECs (human umbilical vein endothelial cells) and HaCat (human immortalized keratinocyte cells). Comparatively, the effect of promoting the proliferation of HUVECs is more significant than that of HaCat. The burn-wound model of rat was developed for evaluating in vivo activity, and the addition of CS effectively promoted wound healing without obvious inflammation according to the IL-1ß and IL-6 staining. This novel paste is expected to provide a promising alternative for wound healing.