Journal of Oral Implantology December 2012 - (Page 805)

LETTER TO THE EDITOR Reliability of Implant Surgical Guides Based on Soft-Tissue Models: A Methodological Mistake Siamak Sabour, MD, PhD1* Elahe Vahid Dastjerdi, DDS, MS2 Key Words: reliability, validity, mistake W e were interested to read the article by Maney and colleagues1 published in this issue of the Journal of Oral Implantology. The authors aimed to assess the reliability of implant surgical guides based on softtissue models and reported that the accuracy was evaluated using software. I found the article’s title to be incorrect and misleading. Moreover, they reported that 22 sites (46.81%) were considered accurate (13 of 24 maxillary and 9 of 23 mandibular sites). As the authors point out in their conclusion, soft-tissue models do not always provide sufficient accuracy for fabricating implant surgical guides. Reliability (precision) and validity (accuracy) are different methodological issues in researches. Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio positive (true positive/false positive), and likelihood ratio negative (false negative/true negative), as well as odds ratio (true results/false results, preferably more than 50), are among the tests used to evaluate the validity (accuracy) of a single test compared to a gold standard.2–4 It is not clear that the reported 22 sites (46.81%) that were considered accurate related to any the aforementioned estimates for validity analysis. Reliability (repeatability or reproducibility) is being assessed by different statistical tests, such as Pearson r, least square, and paired t test, all of which result in common mistakes in reliability analysis.5 Briefly, for quantitative variable intraclass correlation coefficient and for qualitative variables, weighted kappa should be used with caution because kappa has its own limitation, too. Regarding reliability or agreement, it is good to know that for computing kappa value, only concordant cells are being considered, whereas discordant cells should also be taken into account to reach a correct estimation of agreement (weighted kappa).2–4 As a take-home message, for reliability and validity analysis, appropriate tests should be applied. REFERENCES 1. Maney P, Simmons DE, Palaiologou A, Kee E. Reliability of Soft Tissue Model Based Implant Surgical Guides. J Oral Implantol. 2012;38:723–727. 2. Jeckel JF, Katz DL, Elmore JG, Wild DMG. Epidemiology, Biostatistics and Preventive Medicine. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2007. 3. Rothman JK, Greenland S, Lash TL. Modern Epidemiology. 3rd ed. Baltimore, Md: Lippincott Williams & Wilkins; 2008. 4. Szklo M, Nieto FJ. Epidemiology: Beyond the Basics. 2nd ed. New York, NY: Jones and Bartlett Publisher; 2007. 5. Bland JM, Altman DG. Agreed statistics: measurement method comparison. Anesthesiology. 2012;116:182–185. Department of Clinical Epidemiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2 Department of Orthodontic, Faculty of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. * Corresponding author, e-mail: s.sabour@sbmu.ac.ir DOI: 10.1563/AAID-JOI-D-12-00176 1 Journal of Oral Implantology 805

Table of Contents for the Digital Edition of Journal of Oral Implantology December 2012

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Lateral Augmentation of the Maxilla and Mandible Using Framework Technique With Allogeneic Bone Grafts
Accuracy of Cone Beam Computerized Tomography and a Three-Dimensional Stereolithographic Model in Identifying the Anterior Loop of the Mental Nerve: A Study on Cadavers
Evaluation of Microgap Size and Microbial Leakage in the Connection Area of 4 Abutments With Straumann (ITI) Implant
Buccal Bone Plate Remodeling After Immediate Implant Placement With and Without Synthetic Bone Grafting and Flapless Surgery: Radiographic Study in Dogs
Evaluation of Soft Tissues Around Single Tooth Implants in the Anterior Maxilla Restored With Cemented and Screw-Retained Crowns
Accuracy of a Newly Developed Cone-Beam Computerized Tomography-Aided Surgical Guidance System for Dental Implant Placement: An Ex Vivo Study
Nasopalatine Canal Position Relative to the Maxillary Central Incisors: A Cone Beam Computed Tomography Assessment
Esthetics in Implant-Supported Prostheses: A Literature Review
Reliability of Implant Surgical Guides Based on Soft-Tissue Models
Clinical Evaluation of Short and Wide-Diameter Implants Immediately Placed Into Extraction Sockets of Posterior Areas: A 2-Year Retrospective Study
Single Stage Immediate Implant Placements in the Esthetic Zone
Removal of Fractured Dental Implant Screw Using a New Technique: A Case Report
Restoration of Failing Maxillary Implant-Supported Fixed Prosthesis With Cross Arch Splinted Unilateral Zygomatic Implant: A Clinical Report
Oral Rehabilitation of Severe Dentoalveolar Trauma: A Clinical Report
Implant Installation With Bone Augmentation and Transmucosal Healing With Demineralized Human Cortical Bone in the Maxillary Anterior Region: Report of 3 Cases
Bone Morphogenic Protein: An Elixir for Bone Grafting—A Review
Orthodontic Considerations in Restorative Management of Hypodontia Patients With Endosseous Implants
Squamous Cell Carcinoma in Association With Dental Implants: An Assessment of Previously Hypothesized Carcinogenic Mechanisms and a Case Report
Indirect Osteotome Maxillary Sinus Floor Elevation: An Update
Reliability of Implant Surgical Guides Based on Soft-Tissue Models: A Methodological Mistake

Journal of Oral Implantology December 2012