Maxillofacial rehabilitation after rhinectomy using two different treatment options: clinical reports

The aim of these clinical reports was to describe two different approaches to prosthetic rehabilitation after facial disfigurement because of a total rhinectomy. A man with a total rhinectomy was scheduled for craniofacial implants in the nasal residual defect. Three oral implants were used instead of craniofacial ones. A conventional framework was designed to connect the prosthesis to the implant abutments in the anterior nasal floor, and a custom-made ball attachment was positioned in the glabella abutment. A woman with a free rectum abdomis flap covering the defect of the middle face was scheduled for a nasal prosthesis. A titanium framework with a novel connection between the eyeglasses and the prosthesis was manufactured. The two clinical reports presented in this article illustrate favourable clinical treatment outcomes in the rehabilitation of disfigurement.     

Nasal stent fabrication involved in nasal reconstruction: Clinical report of two patient treatments

Total or near-total rhinectomy during tumor ablative surgery creates a large postsurgical defect. Surgical or prosthetic reconstruction may be considered. Surgical reconstruction of such a defect depends on support of the reconstructive tissues to prevent collapse. Without support, the esthetic results and airway patency are compromised. The purpose of this clinical report is to present the use of a nasal stent to support soft and hard tissues for the reconstruction of near-total rhinectomy in 2 patients.     

Digital Versus Conventional Impressions in Fixed Prosthodontics: A Review

Purpose

To conduct a systematic review to evaluate the evidence of possible benefits and accuracy of digital impression techniques vs. conventional impression techniques.

Materials and Methods

Reports of digital impression techniques versus conventional impression techniques were systematically searched for in the following databases: Cochrane Central Register of Controlled Trials, PubMed, and Web of Science. A combination of controlled vocabulary, free‐text words, and well‐defined inclusion and exclusion criteria guided the search.

Results

Digital impression accuracy is at the same level as conventional impression methods in fabrication of crowns and short fixed dental prostheses (FDPs). For fabrication of implant‐supported crowns and FDPs, digital impression accuracy is clinically acceptable. In full‐arch impressions, conventional impression methods resulted in better accuracy compared to digital impressions.

Conclusions

Digital impression techniques are a clinically acceptable alternative to conventional impression methods in fabrication of crowns and short FDPs. For fabrication of implant‐supported crowns and FDPs, digital impression systems also result in clinically acceptable fit. Digital impression techniques are faster and can shorten the operation time. Based on this study, the conventional impression technique is still recommended for full‐arch impressions.     

Combining Conventional Impressions and Intraoral Scans: A Technique for the Treatment of Complete Denture Patients with Flabby Tissue

The conventional method for impressions of flabby tissue uses modified trays and highly flowable materials, but mucostatic impressions are difficult to achieve due to the viscous and the elastic natures of impression materials. In this report, a technique is presented in which conventional impression and intraoral scanning for a fully edentulous patient with flabby tissue are combined. The definitive impression was obtained by applying appropriate pressure to each tissue area, and the denture can be maintained passively and stable at rest and during function.     

Implant-Retained Nasal Prosthesis for a Patient Following Partial Rhinectomy: A Clinical Report

Prosthetic rehabilitation of facial defects has always perplexed maxillofacial prosthodontists. Facial defects lead to functional and cosmetic deficiencies. Early rehabilitation improves patients' quality of life. Osseointegrated rehabilitation of the maxillofacial prosthetic patient presents the potential for overcoming many of the disadvantages associated with conventional retentive methods. This paper presents the clinical report of a patient who had undergone partial rhinectomy due to basal cell carcinoma. Following post-surgical healing, the patient was rehabilitated with a temporary acrylic resin nasal prosthesis retained by eyeglass frame. Later a silicone nasal prosthesis supported by an implant-retained framework was fabricated as a definitive replacement.     

Intraoral Digital Impression Technique: A Review

With the techniques of computer‐aided design and computer‐aided manufacturing (CAD/CAM) being applied in the field of prosthodontics, a concept of intraoral digital impressions was put forward in the early 1980s. It has drawn comprehensive attention from dentists and has been used for dental prosthesis fabrication in a number of cases. This new digital impression technique is expected to bring about absolute digitization to the mode of prosthodontics. A few published articles have indicated that dental prostheses fabricated from intraoral digital impressions have exhibited remarkable advantages over those from conventional impressions in several respects. The present review discusses intraoral digital impression techniques in terms of the following aspects: (1) categories and principles of intraoral digital impression devices currently available; (2) operating characteristics of the devices; and (3) comparison of the manipulation, accuracy, and repeatability between intraoral digital impression and conventional impression.     

Full arch scans: conventional versus digital impressions--an in-vitro study

The digital intraoral impression has become a central part of the CAD/CAM technique. The objective of the present study was to compare the accuracy (trueness and precision) of digital impressions of the full arch with that of conventional impressions on the in-vitro model. For this purpose, a master model was acquired with a new reference scanning process, the measuring trueness of which was +/- 4.1 microm and the precision +/- 2.5 microm. On the one hand, conventional impressions and then plaster models (n = 5) were produced from this master model, and on the other hand, digital impressions were made with the Cerec AC Bluecam and the Lava COS system (each n = 5). The plaster models were also scanned with the reference scanner. The available data records were superimposed and the differences determined. The deviation from the master model defines the trueness of the impression method. The deviations of the models among one another demonstrate the precision of the method. The trueness of the impressions was 55 +/- 21.8 microm in the conventional impression group, for digital impressions with Cerec Bluecam it was 49 +/- 14.2 microm and for digital impressions with Lava COS 40.3 +/- 14.1 microm. The precision was 61.3 +/- 17.9 microm for conventional impression with Impregum, 30.9 +/- 7.1 microm for digital impression with the Cerec Bluecam and 60.1 +/- 31.3 microm for digital impression with Lava COS. These in-vitro results show that accuracy of the digital impression is similar to that of the conventional impression. These results will have to be confirmed in further clinical studies.     

Prosthetic rehabilitation of a total rhinectomy patient resulting from squamous cell carcinoma of the nasal septum: a clinical report

The clinical characteristics and prosthetic rehabilitation of a patient with squamous cell carcinoma of the nasal septum after combined radiation therapy and a total rhinectomy is presented.     

Manufacturing implant supported auricular prostheses by rapid prototyping techniques

Maxillofacial prostheses are usually fabricated on the models obtained following the impression procedures. Disadvantages of conventional impression techniques used in production of facial prosthesis are deformation of soft tissues caused by impression material and disturbance of the patient due to. Additionally production of prosthesis by conventional methods takes longer time. Recently, rapid prototyping techniques have been developed for extraoral prosthesis in order to reduce these disadvantages of conventional methods. Rapid prototyping technique has the potential to simplify the procedure and decrease the laboratory work required. It eliminates the need for measurement impression procedures and preparation of wax model to be performed by prosthodontists themselves In the near future this technology will become a standard for fabricating maxillofacial prostheses.     

Implant-retained nasal prosthesis for reconstruction of large rhinectomy defects: the Salisbury experience

The authors report their experience with 34 patients who had large full thickness nasal defects reconstructed with an implant-retained prosthesis. Their technique of modifying post-rhinectomy defects is described and factors influencing implant success are evaluated. 111 implants were placed to retain a nasal prosthesis. Age, sex and tumour histology did not affect the outcome. Smoking, extent of rhinectomy, use of radiotherapy (pre- and post-implant), hyperbaric oxygen, length and location of the implant and type of retention (bar/magnets) influenced implant success. The overall success rate was 89% (99/111); 94% in patients who did not receive radiotherapy and 86% in those who did. The prosthesis was in place in all patients (100%) at the time of last follow up. Post-rhinectomy defect modification enables adequate access for safe placement of long implants with good primary stability and helps the maintenance of good hygiene (further enhanced by the use of skin grafts). The authors think implant-retained prosthesis is a reliable option for reconstructing large full thickness rhinectomy defects. They suggest their technique of modifying the defect, use of long implants and magnets for retention is responsible for the high success rate of implants used to retain a nasal prosthesis.     

Randomized controlled clinical trial of digital and conventional workflows for the fabrication of zirconia-ceramic fixed partial dentures. Part I: Time efficiency of complete-arch digital scans versus conventional impressions

Statement of problem

Clinical trials are needed to evaluate digital and conventional technologies for providing fixed partial dentures.

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目的 评价末端游离缺失患者使用不同印模材制取功能性印模过程中以及义齿修复后的临床疗效.方法 选择2011年2-9月在山西医科大学口腔医院修复科就诊的末端游离缺失患者40例,随机分为A组和B组(各20例),分别使用印模膏加藻酸盐印模材和硅橡胶(重体加轻体)制取印模,常规方法制作义齿,比较制取印模过程中以及义齿戴用3个月后患者的满意度.结果 制取印模过程中,患者对硅橡胶印模材的满意度高于印模膏加藻酸盐印模材(P＜0.05);义齿戴用3个月后,患者对印模膏加藻酸盐印模材组的满意度较硅橡胶印模材组高,差异均有统计学意义(P＜0.05).结论 可摘局部义齿修复末端游离缺失时,使用印模膏加藻酸盐印模材制取功能性印模其义齿修复效果好,但制取印模过程中患者感觉用硅橡胶印模材较舒适.由此可见,不同的印模材具有各自的优越性,要根据临床需要进行选择.     

Accuracy of impression and pouring techniques for an implant-supported prosthesis

PURPOSE: The purpose of this in vitro study was to compare the dimensional accuracy of a stone index and of 3 impression techniques (tapered impression copings, squared impression copings, and squared impression copings splinted with acrylic resin) associated with 3 pouring techniques (conventional, pouring using latex tubes fitted onto analogs, and pouring after joining the analogs with acrylic resin) for implant-supported prostheses. MATERIALS AND METHODS: A mandibular brass cast with 4 stainless steel implant-abutment analogs, a framework, and 2 aluminum custom trays were fabricated. Polyether impression material was used for all impressions. Ten groups were formed (a control group and 9 test groups formed by combining each pouring technique and impression technique). Five casts were made per group for a total of 50 casts and 200 gap values (1 gap value for each implant-abutment analog). RESULTS: The mean gap value with the index technique was 27.07 microm. With the conventional pouring technique, the mean gap values were 116.97 microm for the tapered group, 57.84 microm for the squared group, and 73.17 microm for the squared splinted group. With pouring using latex tubes, the mean gap values were 65.69 microm for the tapered group, 38.03 microm for the squared group, and 82.47 microm for the squared splinted group. With pouring after joining the analogs with acrylic resin, the mean gap values were 141.12 microm for the tapered group, 74.19 microm for the squared group, and 104.67 microm for the squared splinted group. No significant difference was detected among Index, square/latex techniques, and master cast (P >.05). CONCLUSIONS: The most accurate impression technique utilized squared copings. The most accurate pouring technique for making the impression with tapered or squared copings utilized latex tubes. The pouring did not influence the accuracy of the stone casts when using splinted squared impression copings. Either the index technique or the use of squared coping combined with the latex-tube pouring technique are preferred methods for making implant-supported fixed restorations with dimensional accuracy.     

Modified soft tissue cast for fixed partial denture: a technique

In process of fabrication of a fixed partial denture, dies are trimmed to expose margins of the preparations. The need for the soft tissue cast is quite evident as the soft tissue emergence profile that surrounds the prepared tooth is destroyed in the process of fabrication. This article describes a modified technique to fabricate the soft tissue cast for the conventional fixed partial denture. The impression made with the polyvinylsiloxane was first poured to prepare the die cast. After retrieval of the cast, the same impression was poured second time with the resin based resilient material to cover the facial and proximal gingival areas. The remaining portion of the impression was poured with the gypsum material. This technique does not require additional clinical appointment, second impression procedure, technique sensitive manipulations with impression, or cumbersome laboratory procedures. The simplicity of this technique facilitates and justifies its routine use in fabrication of the fixed partial denture.     

Total nasal reconstruction using composite radial forearm free flap and forehead flap as a one-stage procedure with minor revision

The refashioning of the many distinct structures necessary for successful anatomical and aesthetic reconstruction of the nose after total rhinectomy is difficult. Several significant operations are needed to produce good aesthetic results with functional patency of the nasal airway. We describe a method using autologous grafts that has produced good results on both occasions when it was done. It has the advantage of only one major operation and one subsequent minor revision.     

Marginal gap of monolithic zirconia endocrowns fabricated by using digital scanning and conventional impressions

Statement of problemThe digital scanning technique has been introduced as an alternative to the conventional impression technique for the fabrication of fixed restorations. However, adequate information is not available on the efficacy of digital scanning for the fabrication of endocrowns regarding their marginal accuracy.PurposeThe purpose of this in vitro study was to compare the marginal gap of endocrowns fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) technology and digital scanning and conventional impression techniques.Material and methodsAn endodontically treated mandibular molar tooth was prepared to receive an endocrown. The impressions were made by using the conventional impression technique with polyvinyl siloxane material (n=11) and digital scanning by using an intraoral scanner (n=11). Endocrowns were fabricated from monolithic zirconia blocks by using a milling machine. Each restoration was seated on the prepared tooth, and the marginal gap was measured by using a video measuring machine at 8 points under magnification. The mean marginal gap for each restoration and the overall mean marginal gap for each group were calculated. Data were analyzed by using a statistical software program. Marginal gaps were compared with the Mann-Whitney U test (α=.05).ResultsThe mean marginal gap was 74 μm for the conventional impression group. A similar mean marginal gap (70 μm) was found for the digital scanning group. No statistically significant difference was found between the groups (P=.375).ConclusionsThe digital scanning technique and the conventional impression technique yielded crowns with comparable marginal adaptation.     

Orofacial rehabilitation with zygomatic implants: CAD-CAM bar and magnets for patients with nasal cancer after rhinectomy and partial maxillectomy

Nasal carcinoma extending into the premaxilla requires radical surgical excision including rhinectomy and partial maxillectomy. Rehabilitation is complex and involves the use of removable prostheses. Three patients treated with zygomatic implants and custom-milled bars to retain an obturator and nasal prosthesis are presented.     

摄影测量与传统印模技术制取牙列缺失种植修复印模精度的比较研究

目的:通过体外实验对比摄影测量与传统印模技术制取牙列缺失种植修复印模的精度。方法:选择1例2019年9月就诊于首都医科大学口腔医学院种植中心的74岁男性上颌牙列缺失患者的上颌石膏模型,其上含螺丝固位基台替代体8个。通过开窗夹板式印模复制该石膏模型,将复制模型作为参考模型。由同1名主治医师用两种方法制取参考模型种植体基台...     

Prosthetic rehabilitation of a patient after partial rhinectomy: a clinical report

Carcinoma of the nasal vestibule often requires radical surgical excision, which results in total or partial loss of the nose followed by radiation therapy. A noninvasive, cost-effective technique for rehabilitation of a patient with squamous cell carcinoma of the nasal vestibule following partial rhinectomy and radiation therapy using heat-polymerizing clear acrylic resin is presented.     

In Vivo and In Vitro Comparison of Internal and Marginal Fit of Digital and Conventional Impressions for Full-Coverage Fixed Restorations: A Systematic Review and Meta-analysis

PurposeThis study aims to evaluate digital and conventional impressions for full-coverage restorations in terms of marginal and internal discrepancies.Study selectionThe analysis included in vivo and in vitro studies reporting the marginal or internal gap of full-coverage restorations that provide both the conventional and digital impression. The PubMed, Cochrane Trials, and Scopus databases were searched. The quality of clinical trials was rated using Cochrane Collaboration's tool, and the quality of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation tool. Heterogeneity among the studies was evaluated, and a meta-analysis with subgroup analysis was conducted whenever it was possible.ResultsThirty-three articles (8 prospective clinical trials and 26 in vitro studies) were selected to extract data after applying the predefined selection criteria. The standard mean difference (SMD) of the meta-analysis for marginal adaptation was ?0.76 (95% confidence interval: ?1.23 to ?0.29) and ?0.59 (95% confidence interval: ?0.93 to ?0.24) for in vitro and in vivo studies, respectively, indicating digital impressions provided significantly less marginal gap than conventional impressions in in vitro studies (P = .002). The impression technique did not significantly influence the internal adaptation.ConclusionsDifferences in marginal adaptation between the digital and conventional groups are not significant for in vivo studies, but for in vitro studies, the digital impression resulted in better marginal adaptation. Based on the Grading of Recommendations, Assessment, Development, and Evaluation approach for marginal adaptation, clinical studies were classified as high confidence and in vitro studies were graded moderate because of the inconsistency. Furthermore, high-quality studies are needed to confirm our results (the International Prospective Register of Systematic Reviews; CRD42017077925).