Accuracy of Conventional and 3D-Printed Casts for Partial Fixed Prostheses.

PURPOSE: To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers. MATERIALS AND METHODS: In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner. All data were exported in STL file format, processed, and sent to five 3D printers. Five casts were manufactured in each printer group: SG (CARES P20, Straumann); FG (Form 2, Formlabs); WG (Duplicator 7, Wanhao); ZG (Zenith D, Zenith); and MG (Moonray S100, Moonray). Measurements of the accuracy (trueness and precision) of the casts obtained from conventional elastomeric impressions and 3D-printing methods were accomplished using a 3D analysis software (Geomagic Control). RESULTS: The FG group showed the lowest values for trueness (indicating a value closer to real dimensions), which were similar to the SG group only (P > .05). MG, WG, and ZG groups presented higher values and were similar compared to each other. Data on precision demonstrated that all 3D-printed groups showed lower values for precision (smaller deviation) when compared to the CG. CONCLUSIONS: The trueness depends on the chosen 3D printer. All of the tested 3D printers were more precise than cast models obtained from conventional elastomeric impressions.

Relationship between soft tissue dimensions and tomographic radial root position classification system for immediate implant installation.

The aim of this study was to evaluate the relationship between soft tissue dimensions and radial root position (RRP) classification for immediate implant placement on maxillary anterior teeth. Maxillary anterior teeth (n = 420) were analyzed in the radial plane of cone beam computed tomography (CBCT) scans. Each tooth was classified according to its RRP: class I, (IA, IB); class II (IIA, IIB) class III; class IV, and class V. Soft tissue thickness at different landmarks, supracrestal soft tissue height, and crestal bone thickness were measured in CBCT. Keratinized tissue width was clinically measured. Gingival phenotype (thick or thin) was evaluated by transparency of the periodontal probe and at the landmark 2 mm from the gingival margin in CBCT. Class I tooth position accounted for 31.7%, class II for 45%, class III for 13.3%, class IV for 0.5%, and class V for 9.5%. The gingival phenotype was associated with RRP (χ2 test, p < 0.05). Soft tissue dimensions were significantly different over RRP classes (ANOVA and Tukey tests, p < 0.05). Types IA and IIA presented both thick soft and hard tissues. When planning immediate implants in the anterior maxilla, soft tissue dimensions evaluation should be incorporated into RRP classification to increase the accuracy and predictability of treatment outcomes.

Accuracy of conventional and 3D printed casts for partial fixed prosthesis.

PURPOSE: To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers. MATERIALS AND METHODS: In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner. All data were exported as an STL file format, processed, and sent to five 3D printers. Five casts were manufactured in each group: SG (CARES P20, Straumann); FG (Form 2, Formlabs); WG (Duplicator 7, Wanhao); ZG (Zenith D, Zenith); and MG (Moonray S100, Moonray). Measurements of the accuracy (trueness and precision) of the casts obtained from conventional elastomeric impressions and 3D-printing methods were accomplished using a 3D analysis software (Geomagic Control). RESULTS: The FG group showed the lowest values for trueness (closer to real dimensions), which were similar to the SG group only (P > .05). Groups MG, WG, and ZG presented higher values and were similar compared to each other. Data on precision demonstrated that all 3D-printed groups showed lower values for precision (smaller deviation) when compared to the control group. CONCLUSION: The trueness depends on the chosen 3D printer. All of the tested 3D printers were more precise than cast models obtained from conventional elastomeric impressions.

Survival rate and peri-implant evaluation of immediately loaded dental implants in individuals with type 2 diabetes mellitus: a systematic review and meta-analysis.

OBJECTIVES: To evaluate the survival rate, success rate, and peri-implant biological changes of immediately loaded dental implants (ILs) placed in type 2 diabetic patients (DM2). MATERIALS AND METHODS: The present study was registered on PROSPERO and followed the PRISMA checklist. The search was performed by the first reviewer in January 2021. The electronic databases used were MEDLINE via PubMed, Cochrane, BVS, Web of Science, Scopus, LIVIVO, and gray literature. The risk of bias analysis was performed using an instrument from the Joanna Briggs Institute. RESULTS: A total of 3566 titles and abstracts were obtained. The qualitative synthesis included 7 studies, while the quantitative synthesis included 5 studies. The meta-analysis of IL in individuals with DM2 compared to nondiabetic individuals showed no significant difference among the groups regarding the survival rate of dental implants (RR = 1.00, 95% CI 0.96-1.04; p = 0.91; I2 = 0%), even if the patient had poor glycemic control (RR = 1.08, 95% CI 0.87-1.33; p = 0.48; I2 = 70%). Meta-analysis of marginal bone loss in IL compared to conventional loading in DM2 patients also showed no significant difference (mean difference = - 0.08, 95% CI - 0.25-0.08; p = 0.33; I2 = 83%). CONCLUSIONS: Type 2 diabetes mellitus does not seem to be a risk factor for immediately loaded implants if the glycemic level is controlled, the oral hygiene is satisfactory, and the technical steps are strictly followed. Clinical relevance Rehabilitation in diabetic individuals is more common due to the highest prevalence of edentulism in this population. It is essential to establish appropriate protocols for loading dental implants.

Dimension of the facial bone wall in the anterior maxilla: a cone-beam computed tomography study.

OBJECTIVE: To determine the thickness of the facial bone wall in the anterior dentition of the maxilla and at different locations apical to the cemento-enamel junction (CEJ). MATERIAL AND METHODS: Two-hundred and fifty subjects, aged between 17 and 66 years, with all maxillary front teeth present were included. Written informed consents were obtained. Cone-beam computed tomography scans were performed with the iCAT unit. This examination included all tooth and edentulous sites in the dentition. The images were acquired by means of the iCAT software and processed by a computer. Measurements of the (i) distance between the CEJ and the facial bone crest and (ii) the thickness of the facial bone wall were performed. The bone wall dimensions were assessed at three different positions in relation to the facial bone crest, i.e., at distances of 1, 3, and 5 mm apical to the crest. RESULTS: The measurements demonstrated that (i) the distance between the CEJ and the facial bone crest varied between 1.6 and 3 mm and (ii) the facial bone wall in most locations in all tooth sites examined was ≤1 mm thick and that close to 50% of sites had a bone wall thickness that was ≤0.5 mm. CONCLUSION: Most tooth sites in the anterior maxilla have a thin facial bone wall. Such a thin bone wall may undergo marked dimensional diminution following tooth extraction. This fact must be considered before tooth removal and the planning of rehabilitation in the anterior segment of the dentition in the maxilla.

A new method to assess and measure palatal masticatory mucosa by cone-beam computerized tomography.

AIM: The aim of this study was to apply a novel method to obtain high-quality images by cone-beam computerized tomography (CBCT) that consistently allowed the determination of the dimensions of the palatal mucosa. MATERIALS AND METHODS: Thirty-one patients participated in this study. At the time of the CBCT scanning, the patients wore a plastic lip retractor and wooden spatulas to retract soft tissues away from the teeth and gingiva. The thickness of the palatal mucosa was obtained at forty different locations on each patient. RESULTS: Retraction of the lips and cheek allowed a clear observation and measurements of the thickness of the palatal masticatory mucosa. The average thickness of the palatal mucosa was 2.92 mm in the canine area, 3.11 mm at the first pre-molar, 3.28 mm at the second pre-molar, 2.89 mm at the first molar and 3.15 mm at the second molar. Statistical differences were observed at different ages and heights of measurements. CONCLUSIONS: A new non-invasive method to consistently obtain high-quality images of the palatal masticatory mucosa is described. Measurements of this mucosa could be obtained at different locations on the palate.

Soft tissue cone-beam computed tomography: a novel method for the measurement of gingival tissue and the dimensions of the dentogingival unit.

UNLABELLED: The dimensions and relationships of the structures of the dentogingival unit have been greatly overlooked because of the inability to easily and precisely determine them. The purpose of the present study was to develop a soft tissue cone-beam computed tomography (ST-CBCT) to improve soft tissue image quality and allow the determination of the dimensions and relationships of the structures of the dentogingival unit. Two separate CBCT scans were obtained from three patients with different periodontal biotypes. The first was a scan following standard methods; however, for the ST-CBCT the patients wore a plastic lip retractor and retracted their tongues toward the floor of their mouths. With the first scan, only measurements of the distance of the cementoenamel junctional (CEJ) to the facial bone crest, and the width of the facial alveolar bone were possible. In contrast, ST-CBCT allowed measurements of the distance of the gingival margin to the facial bone crest, the gingival margin to the CEJ, and width of the facial gingiva. ST-CBCT scans allowed a clear visualization, measurement of the dimensions, and analysis of the relationship of the structures of the periodontium and dentogingival attachment apparatus. CLINICAL SIGNIFICANCE: The dimensions and relationships of the structures of the dentogingival attachment apparatus are essential aspects in many fields of dentistry and this report describes a simple, novel, and noninvasive technique to determine them. This technique may aid clinicians in the planning and execution of procedures in several dental specialties.

Effect of calcitonin on bone formation around titanium implant: a histometric study in rabbits / Efeito da calcitonina sobre a formação óssea ao redor de implantes de titânio: um estudo histométrico em coelhos

O reparo ósseo ao redor de implantes de titânio tem sido avaliado, entretanto o efeito de medicamentos, tais como calcitonina, durante o período de maturação óssea ao redor de implantes de titânio não tem sido investigado. A proposta deste estudo foi avaliar o efeito da administração de calcitonina no período tardio de reparo ósseo após a colocação de implantes de titânio. Vinte e sete coelhos Nova Zelândia adultos receberam um implante em cada fêmur. Treze animais foram escolhidos aleatoriamente para compor o grupo teste (calcitonina-2 UI/kg) e quatorze o grupo controle (solução salina). Os animais foram sacrificados 6, 8, 12, e 18 semanas após o procedimento cirúrgico. Os parâmetros analisados foram o comprimento do osso endosteal/periosteal (EB/PB), a área do osso endosteal/periosteal (EBA/PBA) e o comprimento total da cortical (TCL) ao redor do implante. Um efeito positivo do tempo foi fortemente observado após 6, 8, 12, e 18 semanas (P<0.05). Em relação ao fator tratamento, foi observado um efeito positivo da calcitonina para as varíaveis EBA e EB após 12 semanas e TCL após 18 semanas. Com base nos resultados do presente estudo, pode-se concluir que a administração de calcitonina de salmão em animais saudáveis pode melhorar a massa óssea nos estágios tardios de reparo ósseo após a colocação de implantes de titânio

Avaliaçäo histométrica da açäo local da calcitonina de salmäo no processo de reparo ósseo: estudo em ratos / Histometrical evaluation of the local effects of salmon calcitonin on the bone healing process: a study in rats

Neste estudo avaliou-se histometricamente a açäo local da calcitonina de salmäo em defeitos ósseos provocados cirurgicamente em fêmur de ratos. As avaliaçöes foram feitas aos 7, 14 e 21 dias após o ato cirúrgico. Näo se observou diferenças estatísticas aos 7 dias, entretanto no período de 14 dias houve diferenças com maior formaçäo óssea no grupo tratado. No período de 21 dias, em ambos os grupos, näo foi possível diferenciar o tecido ósseo neoformado e o adjacente. os resultados demonstraram, que o efeito da calcitonina foi observado somente no início do processo de reparo dos defeitos ósseos criados cirurgicamente

Creeping attachment associado a enxerto gengival livre / Greeping attachment associated with free gingival graft

O objetivo deste trabalho é o relato de um caso clínico de enxerto gengival livre em paciente jovem com ausência de mucosa queratinizada e recessäo gengival na regiäo de incisivos centrais inferiores. O acompanhamento clínico, ao longo de dois anos, mostrou a ocorrência de creeping attachment, com significativo aumento da faixa de mucosa queratinizada e completo recobrimento radicular