Radiographic Template Research Articles

Radiographic markers for merging virtual data sets

A procedure for registering digital intraoral surface scans onto cone beam computed tomography in the presence of significant scatter artifact is described. The technique uses chairside-fabricated composite resin markers placed on well-distributed teeth to serve as common landmarks in each digital data set for accurate registration. This straightforward, noninvasive, and cost-effective technique facilitates registration without the need for a specialized armamentarium or radiographic templates.

Digital templating without a calibration marker is accurate at predicting implant size for hip hemiarthroplasty.

This study aims to assess the accuracy of digital templating for hip hemiarthroplasty using radiographs without calibration. Two independent, blinded observers retrospectively utilised digital software to template 50 consecutive patients who had hip hemiarthroplasty. The templated parameters (head size, offset and stem size) derived from pre-operative radiographs were compared to the actual prosthetic sizes used intra-operatively. Inter and intra-observer variabilities were calculated. Both observers correctly templated the offset and head size (± 2mm) used in 90% (n = 45) of cases. The femoral stem size (± 1 size) was correctly predicted by templating in over 84% of the cases (n = 42). Inter-observer agreement was excellent for femoral head size with an intra-class correlation coefficients (ICC) of 0.94, substantial for offset (k = 0.7) but only fair for stem size (k = 0.27). ICC values comparing the actual prostheses inserted with the template values were excellent for head size (ICC = 0.96), substantial to near perfect for offset (k = 0.78, 0.85) and fair to moderate (k = 0.24, 0.45) for stem size. Digital templating of radiographs without calibration can be used to accurately and reliably predict femoral head size and offset at a set magnification of 120%. Femoral stem size, however, is more difficult to template adequately on pre-operative radiographs without calibration.

Positional accuracy of a prosthetic treatment plan incorporated into a cone beam computed tomography scan using surface scan registration

Statement of problemThe registration of surface scans onto cone beam computed tomography (CBCT) scans has been proposed as a method of visualizing different anatomic structures and the prosthetic treatment plan simultaneously. This method also overcomes some of the problems associated with conventional radiographic templates. However, it has not been thoroughly investigated or validated for use in implant dentistry. PurposeThe purpose of this in vitro study was to evaluate the accuracy of a prosthetic treatment plan surface scan incorporated into a CBCT scan and to compare it to conventional radiographic templates for single tooth replacement. Material and methodsDirect surface scans of a completely dentate master model with removable radiopaque teeth were made using an intraoral scanner, and indirect surface scans of a stone duplicate of the master model were made using a laboratory scanner. To simulate a clinical scenario, the mandibular left first molar was removed. A CBCT scan of the clinical scenario was made. The surface scans were registered onto the CBCT scans. Radiographic templates for the clinical scenario were fabricated, and the master model was subsequently scanned using the same CBCT scanner with each radiographic template seated. Metrology software was used to assess the accuracy of each method by measuring the 3-dimensional deviation on standard tessellation language (STL) files generated from the CBCT scans against an STL file of the completely dentate master model generated from a CBCT scan. One-way ANOVA and the Tukey HSD test were used for statistical analysis (α=.05). ResultsThe incorporation technique had a significant effect on deviation from the master model (P=.004). The overall mean 3-dimensional deviation was 0.04 mm for direct surface scan registrations, 0.03 mm for indirect surface scan registrations, and 0.33 mm for radiographic templates. Radiographic templates were significantly less accurate compared with both surface scan registration methods (P<.001), whereas no statistically significant difference in accuracy was found between the registration of a laboratory scan and that of an intraoral scan (P=.94). ConclusionsIntraoral and laboratory surface scan registration on CBCT scans were more accurate than radiographic templates for prosthetic treatment plan incorporation. The accuracy of the registration of an intraoral scan and a laboratory scan was comparable.

A New Type of Radiographic Template for Presurgical Radiographic Examination in Implant Restorations

A New Type of Radiographic Template for Presurgical Radiographic Examination in Implant Restorations

Effect of length and location of edentulous area on the accuracy of prosthetic treatment plan incorporation into cone-beam computed tomography scans.

Effects of length and location of the edentulous area on the accuracy of prosthetic treatment plan incorporation into cone-beam computed tomography (CBCT) scans has not been investigated. To evaluate the effect of length and location of the edentulous area on the accuracy of prosthetic treatment plan incorporation into CBCT scans using different methods. Direct digital scans of a completely dentate master model with removable radiopaque teeth were made using an intraoral scanner, and digital scans of stone duplicates of the master model were made using a laboratory scanner. Specific teeth were removed to simulate different clinical situations and their CBCT scans were made. Surface scans were registered onto the CBCT scans. Radiographic templates for each clinical situation were also fabricated and used during CBCT scans of the master models. Using metrology software, three-dimensional (3D) deviation was measured on standard tesselation language (STL) files created from the CBCT scans against an STL file of the master model created from a CBCT scan. Statistical analysis was done using the MIXED procedure in a statistical software and Tukey HSD test (α =.05). The interaction between location and method was significant (P = .009). Location had no significant effect on registration methods (P > .05), but on the radiographic templates (P = .011). Length of the edentulous area did not have any significant effect (P > .05). Accuracy of digital image registration methods was similar and higher than that of radiographic templates in all clinical situations. Tooth-bound radiographic templates were significantly more accurate than the free-end templates. The results of this study suggest using image registration instead of radiographic templates when planning dental implants, particularly in free-end situations.

THE ACCURACY OF IMPLANT POSITIONING USING BONE SUPPORTED VERSUS MUCOSA SUPPORTED SURGICAL GUIDE TEMPLATES FOR IMPLANT ASSISTED LOWER COMPLETE OVERDENTURE

Purpose: Evaluation of the accuracy of implants position using two different types of computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides, including bone supported and mucosa supported guided templates. Materials and methods: Twelve completely edentulous patients were selected for this study and divided into two groups six each. all patients received a radiopaque radiographic template. A cone beam computed tomography was taken to simulate the position of the two implants, virtual implants were drawn in its place, fabrication of surgical guide template using rapid prototyping technique to match the position of virtual implant according to patient’ group. Group I bone supported surgical guide(BSG) and group II mucosa supported surgical guide (MSG). The implants were installed for each patient using surgical guide templates according to the group. The positions and angulations of the placed implants in comparison to those of the planned ones were determined using special software that matched pre- and postoperative computed tomography (CT) images, and deviations were calculated and compared between the two guide templates using a software program to detect any difference in linear and angular deviation. Data were collected; tabulated and analyzed using student T test. Results : There was no significant difference of both linear and angular measurements between virtual and the surgically placed implants for both groups. Also there was insignificant difference in accuracy between group I (bone supported) and group II (mucosa supported). Conclusions: Using template-guided surgery enables the clinician to optimize implant position, angle, diameter and length by dictating the drilling position and angulation. Cone beam CT has accurate measurements in distances between two implants as clinical measurements. The bone supported surgical guide as well as the mucosa supported surgical guide has the same accuracy in implant positioning.

Adaptation of an interim partial removable dental prosthesis as a radiographic template for implant placement

Adaptation of an interim partial removable dental prosthesis as a radiographic template for implant placement

Maxillary and mandibular immediately loaded implant-supported interim complete fixed dental prostheses on immediately placed dental implants with a digital approach: A clinical report

This clinical report describes the treatment of maxillary and mandibular immediate implant placement and immediately loaded implant-supported interim complete fixed dental prostheses with a contemporary digital approach. The virtual diagnostic tooth arrangement eliminated the need for a customized radiographic template, and the diagnostic data collection required for computer-guided surgery (digital diagnostic impressions, digital photographs, and a cone beam-computed tomography [CBCT] scan) was completed in a single visit with improved workflow efficiency. Computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated surgical templates and interim prosthesis templates were made in a dental laboratory to facilitate computer-guided surgery and the immediate loading process.

Computer-guided implant surgery and immediate loading with a modifiable radiographic template in a patient with partial edentulism: A clinical report

Computer-guided implant surgery in fresh extraction sites is an underdeveloped procedure. The presence of teeth that will be extracted makes the creation of an appropriate radiographic template for virtual simulation of the rehabilitation impossible. A modified radiographic template is presented to define a digital restorative simulation for the maxillary rehabilitation of a patient with partial edentulism. This modification enables 3-dimensional prosthetic virtual information in regions where teeth will be extracted.

A new technique to identify the location of the mucogingival junction on computer tomographic scans before implant placement.

A new technique is presented to identify the location of mucogingival junction (MGJ) on CT scans before implant placement. This case report describes the step-by-step fabrication of a radiographic template, which when used in conjunction with CT scans enables the clinician to locate the position of MGJ before implant placement and predict the amount of keratinized tissue (KT) that will be present around an implant. Using this technique, the operator can determine whether or not flapless implant surgery may be a treatment option and whether simultaneous soft tissue augmentation will be necessary at the time of implant placement to establish an adequate band of KT.

A subtractive radiographic template for computer-guided surgery

The procedure for creating a computer-aided design/computer-aided manufactured surgical template with the NobelClinician software was originally designed for the completely edentulous arch. With the development of new techniques and expanded functions in the software, guided surgery for the partially edentulous became a viable option. As of yet, few protocols have been reported for the guided surgery of immediate implants with the NobelClinician software. A new technique is described whereby the radiographic template is modified to allow the use of guided surgery for the immediate placement of dental implants after extractions.

Application of digital diagnostic impression, virtual planning, and computer-guided implant surgery for a CAD/CAM-fabricated, implant-supported fixed dental prosthesis: A clinical report

This clinical report demonstrated theuse of an implant-supported fixed dental prosthesis fabricated with a contemporary digital approach. The digital diagnostic data acquisition was completed with a digital diagnostic impression with an intraoral scanner andcone-beam computed tomography with a prefabricated universal radiographic template to design a virtual prosthetically driven implant surgical plan. A surgical template fabricated with computer-aided design and computer-aided manufacturing (CAD/CAM) was used to perform computer-guided implant surgery. The definitive digital datawere then used to design the definitive CAD/CAM-fabricated fixed dental prosthesis.

Computer-designed selective laser sintering surgical guide and immediate loading dental implants with definitive prosthesis in edentulous patient: A preliminary method.

Objective:The aim of this study was to analyze a preliminary method of immediately loading dental implants and a definitive prosthesis based on the computer-aided design/computer-aided manufacturing systems, after 2 years of clinical follow-up.Materials and Methods:The study comprised one patient in good general health with edentulous maxilla. Cone beam computer tomography (CBCT) was performed using a radiographic template. The surgical plan was made using the digital imaging and communications in medicine protocol with ImplantViewer (version 1.9, Anne Solutions, Sao Paulo, SP, Brazil), the surgical planning software. These data were used to produce a selective laser sintering surgical template. A maxilla prototype was used to guide the prosthesis technician in producing the prosthesis. Eight dental implants and a definitive prosthesis were installed on the same day. A post-operative CBCT image was fused with the image of the surgical planning to calculate the deviation between the planned and the placed implants positions. Patient was followed for 2 years.Results:On average, the match between the planned and placed angular deviation was within 6.0 ± 3.4° and the difference in coronal deviation was 0.7 ± 0.3 mm. At the end of the follow-up, neither the implant nor the prosthesis was lost.Conclusions:Considering the limited samples number, it was possible to install the dental implants and a definitive prosthesis on the same day with success.

A multimodal approach in total hip arthroplasty preoperative templating

Accurate preoperative planning is mandatory for a successful total hip arthroplasty (THA). Templating helps to achieve multiple technical goals, including offset restoration, leg-length equality, and components positioning. This study aims to measure how successful a new stepwise method for preoperative radiographic templating is in achieving postoperative restoration of anatomy. We measured the relationship of several radiographic landmarks on the affected limb in comparison to the unaffected limb to define the appropriate position of the components. One hundred consecutive patients with unilateral disease undergoing THA were retrospectively analyzed. The preoperative templates were compared with the postoperative radiographs. Accuracy in achieving the desired offset, leg-length discrepancy within 5mm, was 93% and 100% respectively. Acetabular component positioning within 2° was replicated in 92%. We conclude that this technique can help the surgeon to accurately reproduce the anatomy of the contralateral unaffected hip.

Preoperative Templating and Computer-Assisted Total Knee Arthroplasty for Arthritic Valgus Knee

We reported the functional outcomes, component alignment and optimal thickness of the tibial inserts and joint line changes of 21 arthritic valgus knee deformities using preoperative templating and computer-assisted total knee arthroplasty(TKA). The osseous cut was modified using a novel preoperative templating technique. Soft tissue balance and component implantation were implemented with the aid of a computed tomography-free navigation system. The arthritic valgus knees had clinical, and functional improvement of the knee Society scores and Lysholm scores postoperatively, at an average of 37.8 ± 7.2 months. The mean anatomic axis (15.2° ± 4.5° vs. 6.1° ± 1.4°) and mechanical axis (8.3° ± 5.2° vs. 0.28° ± 1.6°) were also significantly improved postoperatively. The mean thickness of tibial inserts and joint line changes was 10.7 ± 1.46 mm and 0.1 ± 1.4 mm. This computer-assisted technique with preoperative radiographic templating is an alternative strategy to improve TKA results in arthritic valgus knees.

How Accurate Is CBCT in Measuring Bone Density? A Comparative CBCT‐CT In Vitro Study

Recently, cone beam computed tomography (CBCT) has become widely used for oral and maxillofacial imaging. Twenty dry mandibles were CBCT and conventional multislice CT scanned to evaluate if there is a statistically significant difference between the bone density values they produce, defined as gray density values, and to determine any correlation between them. Using software and a radiographic template, the CT and CBCT scan images were overlapped, and two data sets were created, each one giving the respective gray values (voxel value [VV] or Hounsfield unit [HU]) of the same area with the same spatial coordinates. For the statistical analysis, t-test, Pearson's correlation, and Pearson's r were used. The differences between the CBCT (VV) and CT (HU) gray density values were statistically significant (p ≤ .05), whereas the Pearson's correlation coefficients and Pearson's r-values demonstrated a statistically significant linear correlation between VV and HU gray density values. The lower radiation dose and reduced costs of CBCT make this a useful substitute for CT; however, this study has shown that, in order to more accurately define the bone density with CBCT, a conversion ratio needs to be applied to the VV.

Using an existing denture to design a radiographic template for a two-implant mandibular overdenture

This article describes a technique for modifying an existing mandibular complete denture for use as a radiographic template with a radiopaque light-activated calcium hydroxide (Ca(OH)(2)) preparation. This allows prosthetically driven treatment planning and the surgical placement of 2 implants to support the existing mandibular denture.

Clinical Accuracy of Flapless Computer-Guided Surgery for Implant Placement in Edentulous Arches

Although flapless computer-guided implant placement provides important benefits, deviations from the planned implant placement in the edentulous arch may pose significant risks. This study evaluated the reliability and accuracy of a flapless computer-guided surgical approach. Computer-generated preoperative implant planning was compared to actual placement by cone-beam computerized tomography (CBCT) scanning of patients before and after surgery. A well-fitting complete denture or optimized prosthetic tooth arrangement was used and converted to a radiographic template. Prior to scanning, esthetics and functional aspects were checked clinically. The implant positions were virtually determined by the implant planning software relative to the bone structure and prospective tooth position. After implant placement, new CBCT scans were obtained for each subject. Software was used to fuse the images of the planned and placed implants, and the locations and axes were compared. The normality of the data distribution was evaluated by the Kolmogorov-Smirnov test. Mean values were compared between groups based on the upper or lower jaws with the t test for independent samples. The level of significance was fixed at 5%. Sixty-two implants were placed in edentulous arches with stereolithographic surgical guides in 14 patients. Damage due to implant placement was not observed in any critical anatomical structure. Compared to the planned implants, placed implants showed mean and standard deviation linear measurements at the cervical, middle, and apical implant portions of 2.17 (± 0.87), 2.32 (± 1.52), and 2.86 (± 2.17) mm, for the maxilla, and 1.42 (± 0.76), 1.42 (± 0.76), and 1.42 (± 0.76) mm, for the mandible, respectively. The angular deviations were 1.93 (± 0.17) and 1.85 (± 0.75) degrees for the maxilla and mandible, respectively. The linear deviation differed significantlybetween the upper and lower jaws, but the angular deviation did not. Flapless computer-guided surgery may be a viable treatment option for rehabilitating the edentulous arch.

A New Surgical Template with a Handpiece Positioner for Use During Flapless Placement of Four Dental Implants to Retain a Mandibular Overdenture

This article describes the fabrication of a new and inexpensive surgical template from a radiographic template for flapless placement of dental implants to retain a mandibular overdenture. A radiographic template with radiopaque metal plate markers is constructed and used as a guide for achieving three-dimensional evaluation of bone using computed tomography (CT). The potential position and angulation of the implants are measured relative to the metal plates using the CT data. The radiographic template is converted into a surgical template by attaching rigid metal rods that guide the handpiece precisely during subsequent drilling procedures.

Validity and reliability of preoperative templating in total hip arthroplasty using a digital templating system

To evaluate the validity, interobserver reliability, and intraobserver reproducibility of a digital templating system, the Mdesk™ in preoperative templating in cemented and reverse hybrid total hip arthroplasty (THA). Validity was evaluated by comparing the planned cup size, stem size, CCD angles, and neck length with the components used in 129 patients operated with cemented and reverse hybrid THA. The reliability was measured by comparing the templating results of two surgeons with each other (interobserver) and the results of two templatings carried out by first surgeon (intraobserver). The leg length discrepancy was measured before and after the operation to assess the templating ability to correct it. The Mdesk™ system showed good validity (kappa value ranged from 0.64 to 0.96), especially when one size over and under the planned size were included. No difference between cemented and cementless stems was found. The interobserver reliability ranged from fair (kappa 0.23) to substantial (kappa 0.61) while the intraobserver reproducibility ranged from substantial (kappa 0.70) to excellent (kappa 0.82). Templating and intraoperative measures succeeded to restore the leg length. The Mdesk™ system has comparable validity and reliability with other templating systems used in clinical practice. We recommend that the same surgeon who does the preoperative radiographic templating to also perform the operation. Further studies are required to evaluate the results of succeeded templating in the long run.