Current knowledge about stackable guides: a scoping review.

PURPOSE: The rise of stereolithographic surgical guides and digital workflow, combined with a better knowledge of materials and loading principle, has enabled the placement of the temporary prosthesis at the time of implant placement. This scoping review aimed to assess the current knowledge available on stackable guides. METHODS: The review focused on fully edentulous or requiring total edentulism patients. The procedure studied was the use of stackable guides for edentulous patients in order to place immediate temporary prostheses. The clinical endpoint was immediate placement of the provisional prosthesis after surgery combined with a prior bone reduction using a stackable guide. RESULTS: 12 case reports or case series articles met inclusion criteria, which did not allow an analysis by a systematic review. The included studies were case reports or case series. Most of the articles showed a base stabilized by 3 or 4 bone-pins, anchored in buccal or lingual part. Regarding the accuracy of bone reduction (ranged from 0.0248 mm to 1.98 mm) and implant placement when compared to planned, only 4 articles reported quantitative data. 11 articles showed an immediate loading with the transitional prosthesis after implant placement. CONCLUSIONS: There are as yet no prospective or comparative studies on the efficiency of this technique. In a reliable way, stackable guides seem to be able to guide the practitioner from the flap elevation to the placement of the temporary screw-retained implant supported prosthesis. Given the lack of studies in this specific field of guided surgery, further studies are needed to confirm the clinical relevance of this technique.

Management of an Implant-Supported Fixed Partial Denture in the Esthetic Zone in a Patient With a Very Limited Mouth Opening: A Case Report.

In the maxillary anterior area, the esthetic integration of prosthetic restorations is a challenge, particularly for screw-retained implant prostheses. This case report presents the management and clinical outcome of an old partial edentulous maxillary jaw in an esthetic zone in a young patient with a very limited mouth opening. This patient was rehabilitated with an implant screw-retained fixed partial denture (FPD) using both digital and conventional techniques.

Assessment of bone density in edentulous maxillae using cone beam computed tomography (CBCT).

INTRODUCTION: In edentulous maxillae, the anterior maxilla is the region of interest for implant placement due to posterior bone resorption and sinus pneumatization. This study aimed to assess variations in bone density in different regions of the edentulous maxilla according to sex and age, using cone beam computed tomography (CBCT). MATERIALS AND METHODS: 69 CBCT from edentulous maxilla were analyzed. Six virtual implants were planned between the maxillary sinuses at incisor, canine, and premolar sites. Bone densities (in Hounsfield units HU) were recorded at six points on the neck, body, and apex of the buccal and lingual areas of each virtual implant. We used the two-sample t-test to compare male and female bone densities, and the Spearman correlation coefficient to analyze the correlation between mean bone density and age. One-way analysis of variance with post hoc pairwise t-tests was used to analyze the differences in density between three sites of the edentulous maxilla and the differences in density between three parts of the implant. The significance level was set at 5%. RESULTS: Mean bone density in males was significantly higher than in females. There was a significant correlation between mean bone density and age in females. Incisor sites showed the highest mean bone density, followed by canine and premolar sites. There was a significant decline in bone density from the neck to the apex. CONCLUSIONS: Bone density varied within and among edentulous maxillae. Bone density of the edentulous maxilla seemed to be influenced by age in women and by sex.

Prosthetic rehabilitation of a completely edentulous maxilla with a sectioned implant-supported screw-retained prosthesis in a multiamputee patient with microstomia: A clinical report.

Providing fixed implant-supported prostheses for edentulous patients with microstomia or limited mouth opening is challenging. The clinical treatment of a patient who was a multiple amputee with microstomia and a complete loss of lips elasticity is described. A custom half-sectioned prosthesis was fabricated to resolve numerous difficulties. A screw-retained complete implant-supported prosthesis was developed from a monolithic zirconia framework supported by 4 implants and with digital scanning and computer-aided design and computer-aided manufacturing of the prosthesis. The protocol achieved a complete screw-retained implant-supported prosthesis and offered a solution for a patient with microstomia and limited mouth opening, leading to improved quality of life.

Lingual foramina of the anterior mandible in edentulous patients: CBCT analysis and surgical risk assessment.

OBJECTIVE: The mandible has various unnamed accessory foramina, and surgery is often performed in the symphyseal area. The aim of this study was to analyze the anatomical characteristics of mandibular lingual foramina with the objective of preventing clinical complications during implant surgery on an edentulous mandible. STUDY DESIGN: A total of 100 cone beam computed tomography scans of completely edentulous patients were included in this study. For each canal, nine measurements were recorded in millimeters: seven length or height measurements and two diameter measurements. The placement of a standard implant was simulated and whether the implant passed through the canal was noted. The results were analyzed by t-test and chi-squared at a significance level of 0.05. Pearson correlation analysis was used to assess the relationship between variables. RESULTS: We identified 309 foramina: 236 medial lingual foramina and 73 lateral lingual foramina. We found no significant relationship between the number of foramina and the age of the individuals, or between diameter and the age or gender of the individuals. The mandibular canal was injured in 32.7 % of implant placement simulations. CONCLUSION: The risk of injury to neurovascular bundles is increased in edentulous patients due to vertical bone resorption.

Cone beam computed tomography analysis of the edentulous mandibular symphysis.

BACKGROUND/PURPOSE: Overdenture with single symphyseal implant is one of the useful clinical approach for elderly edentulous patients. We aimed to evaluate edentulous patients with regards to the relationship between dimensions, bone characteristics, cancellous densities, and cortical thickness of the mandibular symphyseal region using cone beam computed tomography (CBCT). MATERIAL AND METHODS: We analyzed 103 CBCT from pre-implant investigations. All included patients were healthy without any disorders affecting bone metabolism. We performed 13 measurements for each patient: 9 of height, width, and thickness (mm) and 4 of density (Hounsfield Units; HU). Fisher's exact test was applied to examine the association between two categorical variables, the Pearson correlation coefficient to measure the strength of linear relationship between two quantitative variables. We used the two-sample Student's t-test to compare mean symphysis height between men and women, the paired Student's t-test to compare mean lingual and buccal cortical thickness. For all tests, the threshold of significance was fixed at 5%. RESULTS: Men and women significantly differed with regards to mean total symphysis height (p = 0.004) and the distribution of Cawood and Howell classifications (p = 0.033). Symphysis height was negatively correlated with mean density of cancellous bone (r = -0.453, p < 0.001). Mean lingual cortical thickness significantly differed from mean vestibular thickness (p < 0.001, paired Student's t-test). CONCLUSION: Present findings supported that symphyseal measurements are parameters that reflect the symphysis bone characteristics, and can guide the choice of a suitable implant design.

A Numeric Analysis of Bone Density in the Edentulous Interforaminal Region.

PURPOSE: The purpose of this study was to assess the density of interforaminal bone using quantitative computed tomography (QCT) in simulated case histories to be prescribed an All-on-Five fixed implant treatment protocol. MATERIALS AND METHODS: QCT scans from 30 edentulous patients (15 men and 15 women; mean age 63.33 ± 9.3 years) were analyzed using the Nobel Clinician software. Densities (in Hounsfield units [HU]) were recorded at the neck, middle part of the body, and apex of the lingual and buccal parts of proposed implant sites. RESULTS: The highest bone densities were measured at the neck of the implant (1,187 ± 382 HU), with lower densities at the apex (774 ± 571 HU) (P < .01). Bone densities decreased on the lingual interforaminal portion of the implant, especially on the two intermediate implants. Bone density was lower in women (917 ± 510 HU) than in men (1,095 ± 601 HU) (P < .01). CONCLUSION: The interforaminal measured bone densities are lower on the paramedian region of the symphysis and in women. However, these levels are in accordance with immediate loading with a fixed partial denture.