Custom Tray Research Articles

Digital workflow for an esthetic rehabilitation using a facial and intraoral scanner and an additive manufactured silicone index: A dental technique

The present article describes a digital workflow for planning an esthetic treatment by using a facial and intraoral scanner, the dental and open-source software design of a facially generated diagnostic waxing, and additive manufactured (AM) clear silicone indices. A virtual design was created to fabricate a unique 3-piece AM index composed of flexible, clear silicone at the labial and lingual aspects and a rigid clear custom tray. The 3-piece AM clear indexes provided advantages compared with conventional procedures, including accurate reproduction of the digital diagnostic waxing, control of index thickness, various insertion paths of the silicone indices, flexibility of the indices, and online storage of the designs.

Effectiveness of a simplified method for final impression in complete denture treatment: A pragmatic clinical trial.

This study aimed to compare two methods for final impression during the fabrication of complete dentures: a traditional method using custom trays (T-group) and a simplified method using the trial denture baseplate (S-group). A pragmatic clinical trial was conducted among edentulous individuals referred for conventional denture treatment. A consecutive sample of edentulous patients was assigned to two groups by cluster randomisation according to the final impression strategy, 30 in the T-group and 38 in the S-group. In the T-group, an auto-polymerising acrylic resin custom tray was used for impression; in the S-group, the final impression was performed using the try-in dentures. For both groups, zinc oxide eugenol paste was used as the impression material. The quality of the dentures was assessed using two rating scales (Functional Assessment of the Dentures and Kapur method). Moreover, clinical time for denture fabrication, number of post-insertion appointments for adjustments, patient satisfaction and post-treatment oral health-related quality of life impacts were also assessed. There were no significant differences between groups regarding prosthodontic and patient-reported outcomes. The S-group demanded less clinical time (P=0.002), with a 23.3% mean reduction in clinical time (P=0.002) and lower number of appointments until the delivery of the dentures (S-group=4.18 vs T-group=5.0; P=0.001). This study showed that the alternative method for final impression is less time-consuming and has similar clinical outcomes when compared to the traditional final impression method. Findings suggest that this alternative may be considered when efficiency is a critical issue in healthcare services.

An update on applications of 3D printing technologies used for processing polymers used in implant dentistry.

Polymer additive manufacturing (AM) technologies have been incorporated in digital workflows within implant dentistry. This article reviews the main polymer AM technologies in implant dentistry, as well as their applications in the field such as manufacturing surgical guides, custom trays, working implant casts, and provisional restorations.

Three-dimensional differences between intraoral scans and conventional impressions of edentulous jaws: A clinical study

Statement of problemUsing intraoral scans for removable dentures has been questioned because of a suggested lack of accuracy. However, data regarding the accuracy of digital intraoral complete-arch scans are sparse, present some methodological issues, and mostly come from in vitro studies on dentate casts, which are very different from edentulous arches. PurposeThe purpose of this clinical study was to evaluate 3D differences between intraoral scans (IOS) and conventional impressions of edentulous arches by means of digital analysis. Material and methodsTen maxillary and 10 mandibular edentulous arches were investigated. For each of them, IOS was performed, and a custom tray was digitally designed based on these scans. Trays were built by using a 3D printer and used to make a conventional impression with a polysulfide impression material. The conventional impression was scanned immediately by using the same intraoral scanner and by the same dentist. Standard tessellation language (STL) files of IOS and the scans of the corresponding conventional impressions (CIS) were superimposed with a 2-phase best-fit alignment in a reverse engineering software program. The corresponding full-scan, 3D mean distance was measured. This procedure was repeated after trimming the IOS and CIS to eliminate peripheral areas not present in both files, as well as nonmatching areas caused by practical aspects related to obtaining the IOS (mobile tissue stretching) and the conventional impressions (mobile tissue compression and folding at the margin of impression), which could have impaired alignment and, consequently, measurement accuracy. The mean distance between the full and trimmed IOS and CIS was statistically investigated, and subgroup analysis was performed for the maxillary and mandibular arches. The statistical significance of the differences between the 2 impression methods was also investigated. ResultsThe full-scan mean distance between the IOS and CIS (−0.19 ±0.18 mm) was significantly different from that of the trimmed scan mean distance (−0.02 ±0.05 mm), with no significant differences for maxillary and mandibular arches. The differences between the IOS and CIS were statistically significant for full scans; they were not significant for trimmed scans, except for the maxillary subgroup. ConclusionsThe mean distance between the IOS and CIS may be significantly different if they are not properly superimposed. The mean distance (−0.02 ±0.05 mm) between the IOS and CIS falls within the range of mucosa resilience. Thus, 3D differences between the IOS and CIS can be attributed to the different physics behind the 2 impression methods and not to defects in accuracy of one method compared with the other. The size of the measured difference between the 2 impression methods was not statistically significant and was not clinically significant for removable denture fabrication.

Accuracy of multi-implant impressions using 3D-printing custom trays and splinting versus conventional techniques for complete arches.

To assess the three-dimensional (3D) accuracy of multi-implant impressions for complete arches obtained using 3D printing technology, and to determine the clinical feasibility of this approach by comparing the results obtained with those obtained with conventional impression techniques. A maxillary model matrix with four implant analogs was used to fabricate 10 stone reference models (control) to simulate edentulous patients. Ten 3D-printed impressions were made using polylactic acid custom open trays with component splinting (3D-printed group). To make 10 conventional impressions of the reference models, the poly(methyl methacrylate) open trays with splinting technique was used (conventional group). Impressions were poured with a type IV dental stone, which had been digitalized utilizing a high-resolution laboratory scanner after connecting the polymer scan bodies. Standard tessellation language (STL) datasets from the two groups of stone models were superimposed with the corresponding reference models. The interimplant distances and interimplant angulations for each implant pair were measured for the reference models and for the two test groups' definitive models, to assess 3D deviations. In addition, the mechanical properties of polylactic acid and poly(methyl methacrylate) tray materials were compared by means of three-point loading and tensile bond tests. The Student t test was used to compare the differences in implant position and mechanical properties between the two groups, while implant angulations were analyzed with Wilcoxon's rank-sum test, at P = .05. There was less implant-position deviation for the 3D-printed group (mean ± SD: 56.37 ± 12.52 μm) than for the conventional group (71.94 ± 18.86 μm) (P = .014). No significant differences were found in angular deviation between the two groups (P > .05). Flexural strength results suggested that polylactic acid (112.7 ± 1.62 MPa) was stronger than poly(methyl methacrylate) (104.0 ± 2.17 MPa; P < .0001). The tensile bond strength of polylactic acid (0.07 ± 0.005 MPa) was higher than that of poly(methyl methacrylate) (0.03 ± 0.004 MPa; P < .0001). The 3D-printing multi-implant impression technique could be an alternative to conventional impression techniques for complete arches.

Accuracy of complete-arch implant impression made with occlusal registration material

Statement of problemWhich impression material, impression tray type, and implant impression technique combination produces the most accurate complete-arch impression is unclear. PurposeThe purpose of this in vitro study was to compare the implant impression accuracy of a completely edentulous arch made with addition silicone occlusal registration material and an open tray with the implant impression accuracy of other conventional impression techniques. Material and methodsA master cast was fabricated from Type IV gypsum with four 3.8-mm diameter implants with internal hexagon located in the area of mandibular canines and first molars. Impressions (N=60) were made from the master cast using the 6 techniques investigated: group B-OC-N with occlusal registration impression material (B), open custom tray (OC), and nonsplinted impression pins (N); group B-OS-N with occlusal registration impression material (B), open plastic perforated stock tray (OS), and nonsplinted impression pins (N); group PE-OC-N with polyether medium-body impression material (PE), open custom tray (OC), and nonsplinted impression pins (N); group PE-OC-S with polyether medium-body impression material (PE), open custom tray (OC), and impression pins splinted (S) with autopolymerizing resin cut after 17 minutes and reconnected; group PE-CC-N with polyether medium-body impression material (PE), closed custom tray (CC), and nonsplinted impression pins (N); group PVS-CS-N with simultaneous double-mix polyvinyl siloxane impression material (PVS), closed stock perforated metal tray (CS), and nonsplinted impression pins (N). Type IV gypsum casts were fabricated 24 hours after making the impressions. A computerized numerical control 3D coordinate measuring machine was used to measure the absolute differences of the distances between the centroids of the 4 implants among the casts produced and the distances measured at the master cast. The Kruskal-Wallis test was used to determine differences among the experimental groups (α=.05). The Mann-Whitney U post hoc analysis was used for all group combinations. ResultsNo significant differences were found between the test groups B-OC-N and PE-OC-S, which were more accurate than the other groups. Group B-OS-N resulted in the least accurate impressions of all experimental groups. Group PE-OC-S resulted in more accurate impressions than the PE-OC-N group. No statistically significant differences were found between groups PE-OC-N and PE-CC-N or between groups PVS-CS-N and PE-CC-N. ConclusionsFor complete edentulism, the use of silicone occlusal registration material with an open custom tray and nonsplinted impression pins resulted in impressions as accurate as those produced with PE open custom tray with splinted impression pins. These 2 techniques resulted in more accurate impressions than the other 4 techniques studied.

Establishment and preliminary clinical evaluation of edentulous custom trays designed and fabricated by chair-side CAD and 3D printing systems

To design and fabricate edentulous custom trays by chair-side computer-aided design and 3-dimensional printing (CAD/3DP) system of independent research and development and to evaluate their clinical effects based on prosthodontists'satisfaction using the visual analogue scale (VAS). Fifteen edentulous patients were randomly recruited by three prosthodontists who passed the unified operating process training. The custom trays for each patient were fabricated using both chair-side CAD/3DP system of independent development and manually conventional method, and the final impressions were made by silicone impression materials (light body). The prosthodontist's satisfaction was surveyed by the three prosthodontists via the questionnaire based on visual analogue scales. In the degree of the prosthodontist's satisfaction of final impressions, the average satisfactions of "try in" (the overall size, shape, convenience, etc.) on the 3DP custom tray made by independent development chair-side system and the manually conventional method were 9.18±0.19 and 8.23±0.22, respectively. The average satisfactions of the border line position (border extensions, frenal notch)were 8.91±0.40 and 7.96±0.23, respectively. The average satisfactions of the stability in border molding were 8.80±0.83 and 8.01±0.81, respectively. The average satisfactions of the quality of final impression (completeness, thickness of impression material, exposure of custom tray, shape of border) were 8.94±0.68 and 7.99±0.42, respectively. The average satisfactions of the difficulty of high quality impression (times of repetition, efficiency) were 9.20±0.37 and 7.88±0.22, respectively. The average satisfactions of the overall satisfaction were 9.11±0.49 and 7.95±0.15, respectively. There was significant difference in the satisfaction of "try in", border line position, stability in border molding, quality of final impression, difficulty of high quality impression, and overall satisfaction between the 3DP custom tray made by chair-side system of independent development and the manually conventional method (P<0.05). In the degree of the prosthodontist's satisfaction of final impression, the 3DP custom tray made by chair-side system of independent development is higher than that of the conventional custom tray, and it meets the clinical requirements and can be popularized in clinical application.

Management of bisphosphonate related osteonecrosis of jaw (BRONJ) with topical drug delivary using custom made tray: A case report

Bisphosphonates (BPs) are effective inhibitors of osteoclast mediated bone resorption and thus frequently used in patients with multiple myeloma, osteoporosis, metabolic bone diseases and metastatic bone cancer. Inspite of its benefits, patients are at increased risk of developingBRONJ which adversely affects their quality of life. BPs induced inhibition of osteoclast function may cause defect in jaw bone physiologic remodeling which along with its antiangiogenic properties may predispose the patient to osteonecrosis of jaw. Here, we present a case in which patient with BRONJ who is terminally ill and only conservative management can be given responded favourably to topical medication using custom trays. Keywords: Bronj, Bisphosphonates, Zolendronate, Osteonecrosis, Custom made tray.

Use of Implant-Supported Custom Milled Impression Copings to Capture Soft-Tissue Contours and Incisal Guidance.

A technique is presented where a custom milled impression coping is used to replicate the clinically established anterior incisal guidance to the definitive prosthesis when multiple implants are restored in the esthetic zone. A conventional impression is initially made, then the stone cast is scanned, and a digitally designed custom screw-retained, implant-supported interim prosthesis is milled from a polymethylmethacrylate (PMMA) billet. This is aimed to digitally design the pontic areas, contour the gingival soft tissue, and establish an anterior incisal guidance. A custom milled impression coping (CMIC) is then fabricated. The CMIC has contours similar to the contours of the interim prosthesis and is fabricated from a PMMA billet. Titanium inserts are placed in the interim prosthesis and the CMIC. The CMIC is inserted intraorally and used for the final impression by using a custom tray and by following the open tray impression protocol. With the proposed technique, the exact contours of the digitally designed and clinically verified interim prosthesis are used to fabricate the definitive restoration.

Clinical evaluation of tissue stops on 3D-printed custom trays

This study evaluated the quality of impressions taken using three-dimensional (3D)-printed custom trays with different tissue stops to optimize the custom tray designs. Different custom trays were designed and printed based on six edentulous patients. These trays were divided into four groups based on the tissue-stop designs: 3DP trays (3D-printed trays without tissue stops), 3DPS trays (3D-printed trays with saddle-shaped tissue stops), 3DPM trays (3D-printed trays with marginal-band tissue stops) and 3DPIM trays (3D-printed trays with inner marginal-band tissue stops). Final impressions were taken using these trays, of which, the 3DP and 3DPIM trays were preborder-moulded. The finished complete dentures were used to take impressions that were set as the reference group to analyse the accuracy of the final impressions. The impressions taken using the 3DP custom trays (preborder-moulded) were used as a reference to analyse the extensions of the impressions taken using the other three custom trays. Randomized block or Friedman tests were used to evaluate each group’s statistical significance. The results revealed that the 3DPIM custom trays with the inner marginal-band tissue stop facilitated the preborder-moulding process and improved the accuracy and extension of the impression.

Masticatory performance of different impression methods for complete denture fabrication: A randomized controlled trial

ObjectivesTo compare the effect of conventional complete dentures fabricated using two different impression methods on masticatory performance and factors relating to masticatory performance in a randomized controlled trial. MethodsA crossover randomized controlled trial was performed with edentulous patients requiring maxillomandibular complete dentures. Mandibular complete dentures were fabricated using two different methods. The conventional method (C) used a custom tray border molded with an impression compound and a silicone. The simplified method (S) used a stock tray and an alginate. Participants were randomly divided into the two groups. In the C–S group, the conventional method was used first, followed by the simplified method; the order was reversed in the SC group. Adjustments were performed four times. The wash out period was 1 month. Masticatory performance as assessed by the mixing of a color-changeable chewing gum (mixing ability). Maximum occlusal force, occlusal contact area, and perceived chewing ability were assessed for each group. ResultsTwenty-seven patients underwent randomization and 24 participants completed the trial. With regard to occlusal contact area, the conventional method showed significantly larger occlusal contact area than the simplified method. No significant differences were observed between the two methods regarding mixing ability, maximum occlusal force, and perceived chewing ability. ConclusionsThis study showed that complete dentures fabricated with the conventional method had a significantly larger occlusal contact area than those made using the simplified method. Clinical SignificanceComplete dentures fabricated with the conventional method, comprising a preliminary impression using alginate in a stock tray followed by a final impression using silicone impression material in a border molded custom tray, resulted in fewer post-insertion adjustments than the simplified method, potentially contributing to earlier stability of new dentures.

Case report: A novel, fixed chairside space maintainer

Introduction: To prevent the dental arch deficiency after untimely loss of primary teeth, a space maintainer is employed. Space maintainers currently in use like band and loop are considered a non-aesthetic appliance. Light Cured Acrylic Resins LCAR are commonly utilized in dental practice. They provide the essential mechanical and physical properties with the necessary characteristics to be used in diverse functions in dentistry. Aim: To provide an aesthetic alternative space maintainer after premature extraction of second primary molar. Case Description: An eight-year-old healthy boy reported with a recently missing lower left second primary molar. A pink color sheet of LCAR Triad® VLC (Custom Tray) product was used to construct a space maintainer. After complete examination, full arch isolation was performed using rubber dam and suction. Both the abutment teeth were cleaned with pumice slurry and then etched with 35% orthophosphoric acid for 30 seconds for primary first molar and 20 seconds for the permanent first molar. The teeth were rinsed, air-dried, and wetted with an adhesive that was light-cured for 20 seconds. A thin layer of flowable composite was applied to the buccal surfaces of the abutment teeth without light-curing it. The cut length of LCAR was placed over the flowable composite extending from the buccal aspect of permanent first molar to buccal aspect of the primary second molar. The ends of the LCAR were adapted to the teeth surfaces with a plastic instrument. The composite and LCAR was light-cured for 2 minutes. for each end of LCAR.Conclusion: This case report showed that the Light Cure Acrylic Resin space maintainers can be a new alternative to the traditionally fixed space maintainers used in pediatric dentistry.

Accuracy of casts produced from conventional and digital workflows: A qualitative and quantitative analyses.

PURPOSEComparing the accuracy of casts produced from digital workflow to that of casts produced from conventional techniques.MATERIALS AND METHODSWhole arch alginate (ALG) and polyvinyl siloxane (PVS) impressions were taken with stock trays and custom trays, respectively. The ALG impressions were poured with type III dental stone, while the PVS impressions were poured with type IV dental stone. For the digital workflow, IOS impressions were taken and physical casts were produced by 3D printing. In addition, 3D printed casts were produced from images obtained from a laboratory scanner (LS). For each technique, a total of 10 casts were produced. The accuracies of the whole arch and separated teeth were virtually quantified.RESULTSWhole arch cast accuracy was more superior for PVS followed by LS, ALG, and IOS. The PVS and ALG groups were inferior in the areas more susceptible to impression material distortion, such as fossae and undercut regions. The LS casts appeared to have generalized errors of minor magnitude influencing primarily the posterior teeth. The IOS casts were considerably more affected at the posterior region. On the contrary, the IOS and LS casts were more superior for single tooth accuracy followed by PVS and ALG.CONCLUSIONFor whole arch accuracy, casts produced from IOS were inferior to those produced from PVS and ALG. The inferior outcome of IOS appears to be related to the span of scanning. For single tooth accuracy, IOS showed superior accuracy compared to conventional impressions.

Evaluation of alpha-adrenomimetic agents for gingival retraction: A randomized crossover clinical trial.

Context:The displacement of the gingiva around the tooth allows proper access during preparation, precise impression taking, and cementation procedures that has a direct bearing on the health of the periodontium. Several methods and agents are used for this purpose.Aims:The primary aim of the study was to clinically evaluate the efficacy of naphazoline as a gingival retraction agent. The secondary aim was to compare it with tetrahydrozoline and aluminum chloride.Settings and Design:Fifteen patients participated in a randomized crossover clinical trial at the Army College of Dental Sciences, Secunderabad, Telangana, India.Subjects and Methods:Preliminary maxillary impressions were made with irreversible hydrocolloid for all patients to fabricate custom trays. After that, baseline impressions and cast for control group measurements were prepared. Gingival displacement was carried out in the right maxillary central incisor for all, with retraction cord soaked in three agents, either, aluminum chloride, tetrahydrozoline, or naphazoline. These agents were used in all patients with a washout period of 14 days. Elastomeric monophase impressions and die stone casts were recorded for each group. The central incisors were sectioned, and gingival retraction was measured using a measuring stereomicroscope.Statistical Analysis Used:The gingival displacement was statistically analyzed using one-way ANOVA and post hoc Bonferroni.Results:Naphazoline had the highest retraction (138.160 μm) followed by tetrahydrozoline (136.039 μm) and aluminum chloride (130.759 μm).Conclusions:Naphazoline, tetrahydrozoline, and aluminum chloride show a clinically and statistically significant amount of displacement when compared to control. Among the three agents, naphazoline showed maximum displacement and maybe a good alternative with fewer side effects.

Evaluation and comparison of tensile bond strength of addition silicone impression material with different tray adhesives

Statement of Problem: Very few studies have been conducted on the comparative evaluation of bond strength of elastomeric impression material to custom tray material using two different universal adhesive systems. Materials and Methods: A special mold was made for the fabrications of 24 samples of tray resin materials. They were divided into two main groups of 12. Perforations followed by adhesive application were done according to the grouping of samples. Polyvinyl siloxane material (medium body) was placed over the samples. A universal testing machine with a crosshead speed of 5 mm/min was used to determine the tensile bond strength of tray resin samples to medium body impression material by using different universal adhesives. Based on these values, Student's “t” test, group statistics, and ANOVA test were applied. Results: By using analysis of variance, there was no significant difference between the strength of bonding of tray resin material and medium body addition silicone by different adhesive systems. Conclusion: It was concluded that Medicept Universal tray adhesive system is as good as 3M™ universal tray adhesive system to achieve a good bond between tray resin and medium body addition silicone.

Comparison of Dimensional Accuracy of Stone Models Fabricated by Three Different Impression Techniques Using Two Brands of Polyvinyl Siloxane Impression Materials

The aim of this study is to check the dimensional precision of stone models made by two different brands of polyvinyl siloxane impression materials using the monophase, one-step, and two-step putty/light-body impression techniques. A metal model, having two crown preparations, was fabricated. With each technique, 40 impressions were made using two types of polyvinyl siloxane impression materials (Aquasil and Virtual). A total of 240 impressions were made with both the polyvinyl siloxane impression materials. Monophase impressions were made with a medium body using an acrylic custom tray. By simultaneous usage of putty and light-body, one-step impressions were made with a perforated metal stock tray. For two-step impressions, a 25-40 microns thick cellophane sheet spacer was used. The stone casts were obtained from the impressions of the stainless steel model. Three different dimensions (height, diameter, and inter-abutment distance) on these resultant stone casts were compared with the standard die. The accuracy of two different brands of impression materials was also compared. The results were then statistically analyzed. The resultant casts obtained from the different impression techniques had significantly larger dimensions in height and diameter, but smaller dimensions were observed for the inter-abutment distance. Larger deviation in resultant casts was observed in the monophase than one-step impression technique and the least deviation was observed in the two-step impression technique. The two-step impression technique produced the most accurate results in terms of the resultant casts. Out of the two different brands, Aquasil produced more fare results. Adequate marginal adaptation, proper fit and least distortion of the castings, and the final prosthesis can be achieved by using the adequate impression technique and impression material.

Influência da moldeira contendo dentifrício na redução da sensibilidade causada por clareamento dental de consultório

Objetivo: avaliar clinicamente a utilização de dentifrício dessensibilizante, aplicado através de moldeira plástica, na redução da dor e variação de cor causadas pela técnica de clareamento dental de consultório. Material e Métodos: Para o estudo foram selecionados 24 voluntários que foram submetidos ao clareamento dental de consultório em 3 sessões clínicas com intervalo de uma semana, com a utilização de gel clareador (peróxido de hidrogênio - 35%). Na noite referente a cada sessão de clareamento, os voluntários utilizaram uma moldeira plástica por 4 horas contendo um dos dentifrícios relativos aos grupos experimentais: (1) Sucralose (S); (2) Fosfato de sódio (FS) e Silicato de cálcio (SC) (Tecnologia NR-5). A dor foi avaliada antes do uso da moldeira plástica com dentifrício (S1, S3, S5) e após (S2, S4, S6) durante 4 semanas, utilizando a escala numérica analógica com escores de 0 a 10. Para a variação de cor (?E) utilizou-se espectrofotômetro (Easyshade). Resultados: O grupo FS e SC apresentaram redução da dor em relação aos demais grupos (p&amp;lt;0,05). Houve uma redução da dor após o uso da moldeira com dentifrício (S2, S4, S6) por 4h e não houve diferença para ?E entre os grupos experimentais após o tratamento clareador (p=0,91). Conclusão: Conclui-se que a utilização de dentifrício dessensibilizante com FS e SC (Tecnologia NR-5) em moldeira plástica foi eficiente para a redução da dor causada por clareamento dental de consultório e o uso de dentifrício dessensibilizante não influenciou a eficácia do tratamento clareador.

A digital implant custom tray fabrication method using the design process for simulating the position of the impression copings and 3D printing technology

The technique described allowed an implant custom tray to be fabricated referencing the location of connected impression copings. The technique uses dental computer-aided design (CAD) software and 3D printing technology. The method controls the thickness of the impression material around the impression copings, improving the impression-making process.

Influence of treatment duration on the efficacy of at-home bleaching with daytime application: a randomized clinical trial.

The aim of this study is to determine whether prolonging the daytime at-home bleaching treatment by 1week increases the bleaching effect without causing more side effects. Fifty participants were randomly divided into two groups, (A) with a 14-day treatment and (B) with a 21-day treatment. A gel with 10% carbamide peroxide was applied for 2h a day in custom trays. Color measurement was performed using a dental spectrophotometer on the right maxillary central incisor and the canine at baseline, at the end of treatment, and 1 and 6months afterwards. Daily, participants recorded their tooth sensitivity and gingival irritation. At the end of the treatment, the ΔE00 of group B (5.77 ± 2.15) was significantly higher than the ΔE00 of group A (4.74 ± 1.94) (p = 0.005 (95% CI: - 2.13 to - 0.39)). After 6months, tooth color was more stable in group B. The ΔSGU values between the different appointment times were higher in the 3-week group. Participants from group B reported more side effects, but statistically, there were no differences compared with group A (p = 0.225 for tooth sensitivity and p = 0.758 for gingival irritation). Daytime application of at-home bleaching for 3weeks achieves greater bleaching results than for 2weeks, immediately after treatment and 1 and 6months afterwards. However, slightly more side effects could occur. When daytime application of at-home bleaching is required, the treatment duration should be prolonged from 2 to 3weeks to achieve greater and more stable results.

Computer-based implant planning involving a prefabricated custom tray with alumina landmark structures

The purpose of this technical report was to describe a method for the fabrication of a custom tray with landmark structures to coordinate cone beam computed tomography and scan data for use in guided implant surgery in patients with numerous artifact-causing metal prostheses. The fabricated custom tray can be used to coordinate cone beam computed tomography data and scan data from the dentition, as well as to fabricate the prostheses.