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 Table of Contents  
ORIGINAL RESEARCH
Year : 2021  |  Volume : 13  |  Issue : 5  |  Page : 478-484

Determining accuracy of sleeveless tooth-supported surgical guide for guided implant surgery: A retrospective observational study


1 Department of Prosthodontics and Crown and Bridge, MGM Dental College and Hospital, Kamothe, Navi Mumbai, Maharashtra, India
2 Procare Dental Clinic, Mumbai, Maharashtra, India
3 Sahyog Dental Studio, Mumbai, Maharashtra, India

Date of Submission15-Apr-2021
Date of Decision06-Aug-2021
Date of Acceptance09-Aug-2021
Date of Web Publication11-Oct-2021

Correspondence Address:
Radhika Pratik Chheda
Department of Prosthodontics and Crown and Bridge, MGM Dental College and Hospital, Junction of NH4 and Sion–Panvel Expressway, Sector 18, Navi Mumbai, Maharashtra.
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JIOH.JIOH_93_21

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  Abstract 

Aim: The advances in CAD/CAM technique have enabled digital data from the virtual setting to be transferred to the real clinical output using surgical guides. Evidence for the accuracy of surgical guides with metal sleeves has been documented. However, the sleeveless surgical guide has not yet been analyzed for its accuracy in clinical situations. The purpose of the study is to determine the accuracy of the sleeveless tooth-supported surgical guide for guided implant surgery. Materials and Methods: This retrospective observational study evaluates data of 25 patients selected randomly with single implants placed using the sleeveless surgical guide, which was collected from a single center at Thane. Cone-beam computed tomography of the treatment planning and the post-implant placement data were superimposed on each other and analyzed using Evalunav (3.0 version, Claronav, Toronto, Canada) software. Descriptive analysis was done. Coronal, apical, and angular deviations were calculated and assessed using a one-sample t-test. Results: It was found that the mean coronal deviation between the planned and placed implants was 0.73± 0.4 mm (0.12–1.81 mm), the mean apical deviation was 0.81± 0.43 mm (0.12–1.66 mm), and the angular deviation was 2.32° ± 0.98° (0°–4.78°). There was a statistically highly significant difference between the achieved and accepted values (P < 0.01) with a lower deviation achieved when compared with the acceptable values. Conclusion: It was concluded that the 3d printed tooth-supported surgical guide with no metal sleeves has acceptable accuracy for placing dental implants using the guided technology.

Keywords: 3d Printing, Accuracy, Dental Implant, Guided Implant Surgery, Surgical Guide


How to cite this article:
Chheda RP, Chheda PS, Shah RM, Chandavarkar S. Determining accuracy of sleeveless tooth-supported surgical guide for guided implant surgery: A retrospective observational study. J Int Oral Health 2021;13:478-84

How to cite this URL:
Chheda RP, Chheda PS, Shah RM, Chandavarkar S. Determining accuracy of sleeveless tooth-supported surgical guide for guided implant surgery: A retrospective observational study. J Int Oral Health [serial online] 2021 [cited 2021 Dec 6];13:478-84. Available from: https://www.jioh.org/text.asp?2021/13/5/478/327874




  Introduction Top


Digital dentistry has evolved enormously to an extent that the replacement of teeth with dental implants has become a common treatment modality. With the advent of CAD-CAM procedures and various types of software, rehabilitation of missing teeth has become more predictable and accurate. The ITI consensus paper on digital implant surgery described two concepts: computer-guided static surgery and computer-navigated dynamic surgery.[1] All these means enable us to place dental implants in a prosthetic and surgically correct position three-dimensionally.

The digital protocol for computer-assisted static technique involves cone beam computed tomography (CBCT) images of the patients, an intraoral scan, or a laboratory scan of the models followed by the superimposition of the two data. Implant planning is done virtually on a computer, and the plan is then transferred to the patient using surgical guides that direct drill placement during surgery.[2] On the contrary, in computer navigation systems, optical assistance and real-time tracking are used to place the implants in the desired position.[3] Theoretically, the concept of computer-guided implant surgeries has numerous benefits in the clinical scenario.[4],[5]

Evidence-based studies show that there is no difference in survival or success of computer-assisted surgery and conventional approach.[6] The surgical guides used in all these studies were with metal sleeves. The limitation of the static technique involves constant verification after each step, as it is a blind procedure. Several possible sources of error during the diagnostic and therapeutic procedure are possible of which reproducibility and stability of the surgical guide are the most important.[7] Also, the use of the guided implant technique is limited by the size of the mouth opening. The surgical instrumentation is bulky, and not all patients have a large enough opening to allow implants to be placed, especially in the molar area.[8] This is due to the presence of a metal sleeve on these guides which requires the use of longer drills to compensate for the increased height.

With advancements in the digital era, surgical guides have evolved from bone-supported to mucosa-supported, milled to 3D printed, and from those incorporating metal sleeves to no sleeves technique. However, all the studies reported have been conducted using the surgical guides with metal sleeves. The sleeveless surgical guide accuracy has not been reported yet. Any change in technology needs to be studied with observational study and trials to determine the reliability of the technology.

The aim of this retrospective study was to determine the accuracy of the 3-D printed surgical guide with no sleeves by comparing the CBCT data of 3-dimensional planning and post-implant placement done using the sleeveless guide.


  Materials and Methods Top


Sampling criteria

Data for the retrospective study were collected from CBCT Centre Digital DentoFacial Concepts, Thane after obtaining the necessary consent from the institution. Sample size was determined using the estimates of mean and standard deviation values from literature, setting the power of the study to be 80%, Type I error to be 5%, and Type II error to be 20%. Therefore, 25 participants were included in the study.[9]

Data of 25 patients with a single implant placed using the sleeveless 3-D printed tooth-supported surgical guide was taken from the individual patient records by an independent operator, not directly involved in the surgical or the prosthetic phase, at the end of the 3-month follow-up period. The data were taken from only one center to avoid any discrepancy in the clarity and other values. The scans included the treatment planning CBCT and the post-implant placement CBCT scans.

Data collection

The present retrospective study evaluated the records of 25 patients who underwent a flapless guided implant surgery procedure with the sleeveless tooth-supported surgical guide fabricated from Digital DentoFacial Concepts. Gender and age have no role in the determination of the accuracy of the guide; therefore, it was not included in the selection criteria. Only delayed implant placement data were included as immediate placement is dependent on numerous clinical factors at the time of extraction. The location of the surgical site was not considered. Only patients with single implant placement were included. The scans of the patients’ mouths or the cast of these cases was all done using the same scanner (3Shape Trios) and saved as an STL file.

The original CBCT data were converted to the Digital Imaging and Communications in Medicine (DICOM) format to produce axial, 3D, panoramic, and cross-sectional images. Using implant planning software (Implant Studio by 3Shape), dental implants were virtually placed according to the bone anatomy and prosthetic design [Figure 1]. The computer-aided design (CAD) of the surgical guide was virtually fabricated (Implant Studio software by 3Shape). This was followed by computer-aided manufacturing (CAM) of the surgical guide to transfer the digital plan to the surgical environment using a 3D printer (Anycubic Photon UV Photocuring printer) [Figure 2]. The sterilized surgical guides with no sleeves were used to conduct guided implant surgery under local anesthesia for all the 25 patients. The implant surgery kit used was compatible with a surgical guide without sleeves (Osstem One Guide kit) [Figure 3]. Post-implant placement CBCT scans were taken and prepared for analysis.
Figure 1: Planning of the implant on the software

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Figure 2: 3D printed sleeveless surgical guide

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Figure 3: Osstem One Guide kit for guided surgeries

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Data evaluation

Data of planning were overlapped on post-placement CBCT data using the Evalunav software (3.0 version, Claronav) [Figure 4]. The planning CBCT and the post-placement CBCT were placed side by side on the screen. Three anatomical markers were identified on the CBCTs to enable accurate superimposition. This was done automatically and refined manually.
Figure 4: Evaluation software for comparing the planned and post-placement data

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The descriptive analysis data, before and after computer-assisted surgery, were collected and analyzed by a single-blinded operator: (1) C-L: coronal linear deviation (distance between the coronal center of the planned and the placed implant); (2) A-L: apical linear deviation (distance between the apical center of the planned and placed implant); (3) A-A: central axis of the placed implant and the planned implant was determined and the angular deviation between the central axes of the implants was measured in degree for each implant. The values were noted down.

Statistical analysis

Data were compiled on an MS Office Excel Sheet (v 2019, Microsoft Redmond Campus, Redmond, WA, USA) and statistically analyzed using Statistical Package for Social Sciences (SPSS v 26.0, IBM). Descriptive statistics such as mean and standard deviation for numerical data have been depicted. Comparison of deviation in the coronal, apical, and angle between the planned and the post-operative CBCT data with standard values was done using a one-sample t-test.

The reliability of measurements was checked through intraclass correlations and Cronbach’s alpha test. For all the statistical tests, P < 0.05 was considered to be statistically significant, keeping α error at 5% and β error at 20%, thus giving power to the study as 80%.


  Results Top


Twenty-five patients’ data with a single implant placed were analyzed in these retrospective data. A summary of the values obtained along with the age (25–50 years) and gender (13 male, 12 female) and the location of these dental implants has been depicted in [Table 1]. These patients were treated using a sleeveless surgical guide fabricated at Digital DentoFacial Concepts, Thane. The protocol used for the placement was according to the guided protocol of Osstem implants using the One Guide kit. The location of the implants was varied and did not have any relevance. However, 10 of these implants were placed in the mandibular molar area.
Table 1: Data for the deviation in the coronal, apical, and angle between the planned and the post-operative CBCT data

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The mean coronal deviation between the planned and placed implants was 0.72 mm, the mean apical deviation was 0.81 mm, and the angular deviation was 2.32°. The range for coronal deviation, apical deviation, and angular deviation was 0.12–1.81 mm, 0.12–1.66 mm, and 0°–4.78°, respectively. The standard deviation observed was 0.4 mm, 0.43 mm, and 0.99° for coronal, apical, and angular deviations, respectively [Table 2]. There was a statistically highly significant difference seen between the achieved and standard values (P < 0.01) with lower deviation achieved when compared with the standard value [Table 2].
Table 2: Comparison of values for coronal deviation (C-L), apical deviation (A-L), and angular deviation (A-A) vs. their respective standard value

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There was an overall excellent internal consistency (alpha-value >0.9). There was an overall almost perfect agreement (single measures value >0.8) with a statistically highly significant P-value (P < 0.01) [Table 3].
Table 3: Intraclass correlations and Cronbach's alpha

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  Discussion Top


With the evolvement of the digital era, the guided surgery has gained popularity. Hultin et al.[3] in their systematic review on the guided implant surgery revealed no obvious differences between conventional and guided implant treatments regarding implant survival rate. It was also observed that the pain and discomfort were comparatively less in flapless guided implant surgery. Global meta-analysis depicted statistically greater accuracy (P < 0.001) in angle and deviation in entry point (MD: 20.53) and apex (MD: 20.65) in the completely guided surgery group than the partially guided surgery group.[10] The advantages of fully guided techniques have been enlisted in various researches, such as flapless technique enhancing biological benefits[11],[12]; better predictability of immediate loading and prefabricated prosthesis[13],[14]; shorter operatory time enhancing patient and clinician comfort[15],[16],[17]; and easier treatment of patients with other health problems.[18],[19]

Research has shown that 3D-printed surgical guides are easy to fabricate, produce less wastage, and are less time-consuming, cost-effective, and statistically as accurate as milled guides.[20] For static guided implant surgery, surgical templates can be categorized according to their functional design as tooth-supported, mucosa-supported, or bone-supported, with or without flap elevation. Therefore, a fully guided system was used for determining the accuracy of the 3D-printed tooth-supported surgical guide where the surgical guide directs the drill direction and position without raising the flap. Arisan et al.[21] concluded that CAD/CAM surgical guides may help in precisely placing dental implants. Rigid screw fixation of a single guide incorporating metal sleeves and a special drill kit further minimizes deviations.

Most of the tooth-supported surgical guides are made of resin with extensions on the adjacent teeth, which use metal sleeves in the templates for guiding the drills at the implant site with the help of diameter reducers.[15],[22],[23],[24] These surgical guides pose several difficulties like the use of longer drills than conventional implant surgery. The longer drills are used in guided surgery, to compensate for the thickness of the guide, the metal sleeves, and the thickness of the mucosa. Moreover, in the molar regions, the mouth opening is less, so it becomes difficult to insert these drills.[22],[23],[25],[26] The metallic sleeves allow insertion of the drills only vertically. Therefore, the limited mouth opening, the presence of opposing teeth along with the limitation of the metal sleeves make the guided protocol with such guides very difficult.[23],[26]

In completely edentulous patients, the lack of fit and stability of the surgical guide pose more problems. The guides often displace from the correct position, which can lead to spatial deviation in the 3-dimensional implant placement originally planned.[8],[22],[23],[27],[28],[29] The lack of stability might result in either buccally or lingually placed implants or too close to teeth or other implants leading to prosthetic and esthetic complications.[8],[23],[27],[28],[29],[30] All these scenarios compel the dental technician to adopt compromise solutions. However, with the newer technologies evolving, the requirement for sleeves has deteriorated.

The One Guide Surgical kit (Osstem) is so designed that it eliminates the need for metal sleeves in the surgical guide. This is because the drills in the kit are designed such that the platform has a designated width and height to fit on the surgical guide, only in one direction. The drawback of the resin guide being abraded while drilling was also eliminated, as the platform is not cutting and it is only the platform that touches the guide, not the cutting surface. Moreover, these drills are shorter than the previous guided kits which enable easy access in the posterior regions where the mouth opening is limited.

Various systems have now adopted the sleeveless technology such as Osstem, Dio Navi, Dentium, Bio horizon, Megagen, CovalMedi, etc. Although this technology has been adopted, the accuracy of these guides has not been evaluated so far.

It has been documented that a linear deviation of more than 2 mm was considered clinically significant, where an angle more than 15° was considered significant (which is the angle above an angled abutment).[31] Schnutenhaus et al.[32] in their study for evaluating the accuracy of sleeveless surgical guide for one-piece implants found the mean coronal, apical, and angular deviations to be 0.52 mm, 0.82 mm, and 2.82°, respectively. In this study, it was found that the mean deviation in coronal, apical, and angular parameters was 0.73 ±0.4 mm, 0.81±0.43 mm, and 2.32± 0.98° with the use of the sleeveless surgical guide and One Guide kit for guided implant placement. The coronal deviation was marginally higher in the present study which can be due to the difference in the type of implant, the system used, etc. However, these values were well within the clinically acceptable limits.

Moreover, these values were compared to the acceptable values, and the results proved the deviation obtained by using the sleeveless surgical guide was comparatively much lower than the standard values (P < 0.01). Therefore, it was determined that the 3D printed surgical guide without any metal sleeves can be used for accurate and precise placement of dental implants. In addition, there is a possibility of adding a lateral window in the surgical guide for inserting the drills from the buccal side to facilitate easy access in the molar area while maintaining accuracy.

The limitation of this study includes the data available for only 25 single implants. The surgical protocol was not monitored in this retrospective study. There is not enough data on the sleeveless surgical guide system available; therefore, further studies will be needed in that direction. Moreover, a prospective study design with a comprehensive approach of evaluation would provide more clear opinions about the accuracy and precision of these surgical guides. Hence, this study does not allow definitive conclusions on the validity of this new system. Also, the comparison of various tooth-supported and mucosa-supported guides was not done. More research needs to be done using these guides to determine the various other aspects to dispel any further doubts on the reliability and accuracy of the system.


  Conclusion Top


Guided surgeries have led to a paradigm shift in implant dentistry. It equips clinicians with better predictability and accuracy. The sleeveless surgical guide in this study has proven to have acceptable accuracy for positioning the implants in a predetermined prosthetically correct position. These surgical guides do not have any metal sleeves; therefore, it eliminates the use of long drills and also becomes less costly. However, future studies are needed to establish the accuracy in different scenarios.

Acknowledgements

We would like to acknowledge Digital DentoFacial Concepts for providing with the data and the consent. We thank Dr. Aishwarya Raut for her help during all processing of data.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Author contributions

Not applicable.

Ethical policy and Institutional Review Board statement

The permission to use the data and publish has been obtained by the Imaging Centre. No imaging was done for the purpose of the study as this was a retrospective study. A copy of it has been attached in the supplementary documents.

Patient declaration of consent

Consent has been taken by the Imaging Centre as declared in the letter submitted to the author.

Data availability statement

Data will be available on request from the author.



 
  References Top

1.
Jung RE, Schneider D, Ganeles J, Wismeijer D, Zwahlen M, Hämmerle C et al. Computer technology applications in surgical implant dentistry: A systematic review. Eur J Esthet Dent 2009;4:348-80.  Back to cited text no. 1
    
2.
Al Yafi F, Camenisch B, Al-Sabbagh M. Is digital guided implant surgery accurate and reliable? Dent Clin North Am 2019;63:381-97.  Back to cited text no. 2
    
3.
Hultin M, Svensson KG, Trulsson M. Clinical advantages of computer-guided implant placement: A systematic review. Clin Oral Implants Res 2012;23(Suppl. 6):124-35.  Back to cited text no. 3
    
4.
Hämmerle CH, Stone P, Jung RE, Kapos T, Brodala N. Consensus statements and recommended clinical procedures regarding computer-assisted implant dentistry. Int J Oral Maxillofac Implants 2009;24(suppl):126-31.  Back to cited text no. 4
    
5.
Sanz M, Naert I; Working Group 2. Biomechanics/risk management (Working Group 2). Clin Oral Implants Res 2009;20(Suppl. 4):107-11.  Back to cited text no. 5
    
6.
Danza M, Zollino I, Carinci F. Comparison between implants inserted with and without computer planning and custom model coordination. J Craniofac Surg 2009;20:1086-92.  Back to cited text no. 6
    
7.
Schneider D, Marquardt P, Zwahlen M, Jung RE. A systematic review on the accuracy and the clinical outcome of computer-guided template-based implant dentistry. Clin Oral Implants Res 2009;20(Suppl. 4):73-86.  Back to cited text no. 7
    
8.
Dolcini GA, Colombo M, Mangano C. From guided surgery to final prosthesis with a fully digital procedure: A prospective clinical study on 15 partially edentulous patients. Int J Dent 2016;2016:7358423.  Back to cited text no. 8
    
9.
Allen JC. Sample size calculation for two independent groups: A useful rule of thumb. Proc Singapore Healthc2011;20:138-40.  Back to cited text no. 9
    
10.
Zhou W, Liu Z, Song L, Kuo CL, Shafer DM. Clinical factors affecting the accuracy of guided implant surgery—A systematic review and meta-analysis. J Evid Based Dent Pract 2018;18:28-40.  Back to cited text no. 10
    
11.
Sclar AG. Guidelines for flapless surgery. J Oral Maxillofac Surg 2007;65:20-32.  Back to cited text no. 11
    
12.
Vohra F, Al-Kheraif AA, Almas K, Javed F. Comparison of crestal bone loss around dental implants placed in healed sites using flapped and flapless techniques: A systematic review. J Periodontol 2015;86:185-91.  Back to cited text no. 12
    
13.
Maló P, de Araújo Nobre M, Lopes A, Francischone C, Rigolizzo M. “All-on-4” immediate-function concept for completely edentulous maxillae: A clinical report on the medium (3 years) and long-term (5 years) outcomes. Clin Implant Dent Relat Res 2012;14:139-50.  Back to cited text no. 13
    
14.
Lopes A, Maló P, de Araújo Nobre M, Sánchez-Fernández E, Gravito I. The NobelGuide® All-on-4® Treatment Concept for rehabilitation of edentulous jaws: A retrospective report on the 7-years clinical and 5-years radiographic outcomes. Clin Implant Dent Relat Res 2017;19:233-44.  Back to cited text no. 14
    
15.
Arisan V, Karabuda CZ, Ozdemir T. Implant surgery using bone- and mucosa-supported stereolithographic guides in totally edentulous jaws: Surgical and post-operative outcomes of computer-aided vs. standard techniques. Clin Oral Implants Res 2010;21:980-8.  Back to cited text no. 15
    
16.
Nkenke E, Eitner S, Radespiel-Tröger M, Vairaktaris E, Neukam FW, Fenner M. Patient-centred outcomes comparing transmucosal implant placement with an open approach in the maxilla: A prospective, non-randomized pilot study. Clin Oral Implants Res 2007;18:197-203.  Back to cited text no. 16
    
17.
Fortin T, Bosson JL, Isidori M, Blanchet E. Effect of flapless surgery on pain experienced in implant placement using an image-guided system. Int J Oral Maxillofac Implants 2006;21:298-304.  Back to cited text no. 17
    
18.
D’haese J, Van De Velde T, Komiyama A, Hultin M, De Bruyn H. Accuracy and complications using computer-designed stereolithographic surgical guides for oral rehabilitation by means of dental implants: A review of the literature. Clin Implant Dent Relat Res 2012;14:321-35.  Back to cited text no. 18
    
19.
de Santis D, Trevisiol L, Cucchi A, Canton LC, Nocini PF. Zygomatic and maxillary implants inserted by means of computer-assisted surgery in a patient with a cleft palate. J Craniofac Surg 2010;21:858-62.  Back to cited text no. 19
    
20.
Henprasert P, Dawson DV, El-Kerdani T, Song X, Couso-Queiruga E, Holloway JA. Comparison of the accuracy of implant position using surgical guides fabricated by additive and subtractive techniques. J Prosthodont 2020;29:534-41.  Back to cited text no. 20
    
21.
Arisan V, Karabuda ZC, Ozdemir T. Accuracy of two stereolithographic guide systems for computer-aided implant placement: A computed tomography-based clinical comparative study. J Periodontol 2010;81:43-51.  Back to cited text no. 21
    
22.
Vercruyssen M, Fortin T, Widmann G, Jacobs R, Quirynen M. Different techniques of static/dynamic guided implant surgery: Modalities and indications. Periodontol 2000 2014;66:214-27.  Back to cited text no. 22
    
23.
Mangano FG, Hauschild U, Admakin O. Full in-office guided surgery with open selective tooth-supported templates: A prospective clinical study on 20 patients. Int J Environ Res Public Health 2018; 15:2361.  Back to cited text no. 23
    
24.
Xu LW, You J, Zhang JX, Liu YF, Peng W. Impact of surgical template on the accuracy of implant placement. J Prosthodont 2016;25:641-6.  Back to cited text no. 24
    
25.
Colombo M, Mangano C, Mijiritsky E, Krebs M, Hauschild U, Fortin T. Clinical applications and effectiveness of guided implant surgery: A critical review based on randomized controlled trials. BMC Oral Health 2017;17:150.  Back to cited text no. 25
    
26.
Saund DS, Pearson D, Dietrich T. Reliability and validity of self-assessment of mouth opening: A validation study. BMC Oral Health 2012;12:48.  Back to cited text no. 26
    
27.
Bencharit S, Staffen A, Yeung M, Whitley D III, Laskin DM, Deeb GR. In vivo tooth-supported implant surgical guides fabricated with desktop stereolithographic printers: Fully guided surgery is more accurate than partially guided surgery. Oral Maxillofac Surg 2018;76:1431-9  Back to cited text no. 27
    
28.
Arunyanak SP, Harris BT, Grant GT, Morton D, Lin WS. Digital approach to planning computer-guided surgery and immediate provisionalization in a partially edentulous patient. J Prosthet Dent 2016;116:8-14.  Back to cited text no. 28
    
29.
Dawood A, Marti B, Sauret-Jackson V, Darwood A. 3D printing in dentistry. Br Dent J 2015;219:521-9.  Back to cited text no. 29
    
30.
Peng YT, Tseng CC, Du YC, Chen YN, Chang CH. A novel conversion method for radiographic guide into surgical guide. Clin Implant Dent Relat Res 2017;19:447-57.  Back to cited text no. 30
    
31.
Valente F, Schiroli G, Sbrenna A. Accuracy of computer-aided oral implant surgery: A clinical and radiographic study. Int J Oral Maxillofac Implants 2009;24:234-42.  Back to cited text no. 31
    
32.
Schnutenhaus S, von Koenigsmarck V, Blender S, Ambrosius L, Luthardt RG, Rudolph H. Precision of sleeveless 3D drill guides for insertion of one-piece ceramic implants: A prospective clinical trial. Int J Comput Dent 2018;21:97-105.  Back to cited text no. 32
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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