Influence of supporting teeth quantity of surgical guide on the accuracy of the immediate implant in the maxillary central incisor: An in vitro study

doi:10.21203/rs.3.rs-4882805/v1

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Influence of supporting teeth quantity of surgical guide on the accuracy of the immediate implant in the maxillary central incisor: An in vitro study

https://doi.org/10.21203/rs.3.rs-4882805/v1

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Introduction: Static computer-assisted implant surgery (sCAIS) aims to enhance precision by guiding the drill during the procedure. The quantity and morphology of supporting teeth influence the accuracy of sCAIS.

Aims: To investigate how the number of supporting teeth affects the accuracy of immediate implant surgery in the maxillary central incisor.

Methods: Twenty-eight upper jaw models, simulating immediate post-extraction sockets of tooth 11, were divided into two groups based on the number of supporting teeth (four or six). Cone beam computed tomography and intraoral scans determined the implant positions, guiding the fabrication of surgical guides and evaluating discrepancies in the planned and actual implant placements, particularly in terms of three-dimensional at the implant platform and apex and angular deviations.

Results: The group with six teeth support had significant differences in angular deviation (3.59 ± 0.97 and 4.63 ± 0.71) and implant apex deviation (1.40 ± 0.27 and 2.08 ± 0.21) values compared to the group with four teeth support. Although other discrepancy variables in the six teeth-supported group exhibited lower values, they did not show statistically significant differences compared to the four teeth-supported group.

Conclusion: The number of supporting teeth may influence the accuracy of sCAIS in immediate implant surgery in the aesthetic dental region. Both groups showed acceptable clinical accuracy, but the surgical guide supported by six teeth may enhance implant accuracy compared to four.

Health sciences/Health care/Dentistry/Dental treatments/Dental implants

accuracy

immediate implant surgery

sCAIS

supporting teeth

surgical guide

Implant placement in the front teeth area requires excellent aesthetic results, and the implant's position plays a crucial role in achieving them. The final prosthesis design and the anatomical conditions of the placement site are essential in determining the optimal implant positioning. Surgical guide systems can accurately transfer the planned implant positions from virtual planning to clinical practice, minimizing any positional discrepancies compared to freehand surgery. This approach helps to reduce the risk of complications arising from inaccuracies, leading to better aesthetic and functional treatment outcomes.^{1, 2}

Immediate implant placement in the front teeth region is commonly required to fulfill aesthetic demands. However, the process of immediate implant surgery is technically complex. It poses several challenges, such as the absence of stable initial implant placement and the risk of drill slippage during the preparation of the bone.^{3, 4, 5} This slippage can cause the drill to move toward weaker areas, which can be problematic. Surgical guide systems can help stabilize the drill during surgery, minimize deviations, and improve treatment outcomes.⁶

An in vitro study by Kholy et al.⁷ the accuracy of surgical guide systems relies on the number and type of supporting teeth. The study showed that guides supported by four adjacent teeth were just as accurate as those supported by the entire maxillary arch, consisting of seven teeth. Additionally, guides supported by posterior teeth were more accurate than those supported by anterior teeth. The study also found that the accuracy of immediate implant placement was lower than that of implants placed in healed sockets. However, the authors did not directly compare the number of supporting teeth during immediate implant surgery. Since there is a common need for immediate implantation in the anterior region where anterior teeth have smaller surface areas than posterior teeth due to their sizes, there is a potential increase in inaccuracies when using surgical guide systems supported by only four teeth.

Therefore, this study aims to evaluate the influence of the number of supporting teeth on the accuracy of surgical guide systems in immediate implant surgery on models simulating upper right central incisor or Federal Dentaire Internationale (FDI) tooth number 11 extraction sockets by comparing angular and three-dimensional (3D) deviations at the platform and apex of the implant during immediate implant surgery with surgical guides supported by four adjacent teeth (4-teeth group) and six adjacent teeth (6-teeth group). The secondary outcome is to evaluate the linear deviations, including buccopalatal, mesiodistal, and apicocoronal deviations at the platform and apex of the implant.

Study design

An in-vitro study was conducted on acrylic resin jaw models simulating human bone with D2 bone density according to Misch's classification in 1985. Each study model featured potential sites of tooth 11 positions corresponding to the FDI index, simulating a freshly extracted socket for immediate implant surgery.

The sample size was determined based on a study by El Kholy et al.⁷, which reported an implant apex deviation of 0.616 ± 0.255 mm when using a surgical guide supported by four teeth. The calculation was done with a type-I error (α) of 0.05 and a power of 0.80 to ascertain the number of implants required for statistical significance. The study expects a reduction in deviation of 0.300 mm with the 6-teeth-supported surgical guides compared with 4-teeth-support. Considering a potential 10% data loss for each group, the study calculated that 28 implants would be a sufficient sample size.

Implant planning

The cone-beam computed tomography (CBCT) system (Orthophos SL 3D, Dentsply Sirona, USA) was used to scan each study model to produce a Digital Imaging and Communication in Medicine (DICOM) file, with the parameter for scanning was 60 kVp, 3 mA voxel size 80 × 80 × 80 µm, field of view 8 × 8 cm. The models were then scanned by an intraoral scanner (TRIOS 4, 3shape, Denmark) to obtain a Standard Tessellation Language (STL) file. An implant planning software coDiagnostiX version 10.6 (Dental Wings, Germany) was used to receive the DICOM and STL files. Two files were superimposed using teeth anatomic landmarks and verified through cross-sectional assessments on CBCT. Exclude tooth 11 from the STL file and create a digital wax-up of tooth 11 in the software. The implant utilized in the study was a 4.1 × 16 mm bone-level tapered implant (Straumann AG, Basel, Switzerland). One skilled doctor planned implants in the ideal position that met both anatomic and prosthetic criteria outlined by Buser⁸ and Resnik⁹ for maxillary anterior implants.

Surgical guide fabrication

The surgical guides were created using the same software and were categorized into two experimental groups based on the number of teeth supporting them during the implant placement protocol. The "4-teeth" group had support from four adjacent teeth: FDI teeth 13, 12, 21, and 22, while the "6-teeth" group had support from six adjacent teeth: FDI teeth 14, 13, 12, 21, 22, and 23. Both groups featured an inspection window at the contact area between FDI teeth 21 and 22 to ensure precise fitting. The offset between the surgical guide and the tooth was 0.05 mm. All surgical guides were 3D printed with a thickness of 2.5 mm using medical grade resin material (DentaGUIDE, Asiga, Australia) with a digital light processing 3D printer with a pixel resolution of 62 µm (MaxUV, Asiga, Australia).

Surgical protocol

The dental models were attached to the phantom head simulator unit in a supine position to simulate the clinical setting (Fig. 1A). Tooth 11 was removed from the study model, surgical guides were then inserted, and the fit and stability of the model were checked through the inspection window (Fig. 1B). An experienced surgeon performed all the implant surgery with the surgical guide. The drilling protocol followed the fully guided protocol according to the manufacturer’s recommendations.

Outcome measurements

After placing the implants, the CBCT was used to scan all study models with the same parameters as before the surgery. The DICOM file was loaded into the coDiagnostiX and superimposed with preoperative DICOM using anatomic-based registration. The actual implant positions were then located by using the CBCT slide in three planes: tangential plane (Fig. 2A), cross-sectional plane (Fig. 2B), and axial plane (Fig. 2C). With the “Treatment evaluation” application of the coDiagnostiX software, the algorithm automatically calculated the angular deviation and the 3D deviation at the implant platform and the implant apex between the placed and planned positions. The primary outcomes were the angular deviation in degrees and 3D deviation in mm at the implant platform and apex (Fig. 3). The secondary outcome was the linear deviation measured in mesiodistal, buccopalatal, and apicocoronal directions at the implant platform and apex. One operator carried out all the procedures and measurements.

Statistical analysis

The data was entered using Microsoft Excel 365 (Microsoft, Washington, U.S.) and analyzed with JASP software version 0.17.2.1 (University of Amsterdam, North Holland, Netherlands). The Shapiro-Wilk test was used to check if the data had a normal distribution. Data were presented as means and standard deviations (SD) for normally distributed data and medians and interquartile ranges (IQR) for data that are not normally distributed. Depending on the normality of the data, either the two-sample t-test or the Mann-Whitney U test was used to compare the angular deviation and 3D deviation at the implant platform and apex, as well as the secondary outcome between the two groups. A p-value of less than 0.05 was considered statistically significant.

3D and angular deviations

The results for 3D and angular deviations are summarized in Table 1. The mean platform deviation for the 4-teeth and 6-teeth groups was 0.90 ± 0.22 mm and 0.79 ± 0.18, respectively. The mean apex deviation for the same group order was 2.08 ± 0.21 and 1.40 ± 0.27 mm, respectively. The mean angular deviation for the two groups was 4.63 ± 0.71 and 3.59 ± 0.97 degrees, respectively. The Shapiro-Wilk test confirmed that all data were normally distributed, allowing the use of two-sample t-tests. In all three parameters measured, the 6-teeth group exhibited lower deviations than the 4-teeth group. Specifically, the 6-teeth group showed a significantly lower 3D deviation and angular deviation at the apex than the 4-teeth group (Fig. 4B and 4C). However, the two groups had no statistically significant difference in 3D deviation at the platform (Fig. 4A).

Table 1

The 3D and angular deviations of the implant in each group.
Group	4-teeth (n = 14)	6-teeth (n = 14)	Overall (n = 28)
3D deviation at platform (mm) Mean ± SD Min-Max Range	0.90 ± 0.22 0.49–1.26 0.77	0.79 ± 0.18 0.49–1.03 0.54	0.84 ± 0.20 0.49–1.26 0.77
3D deviation at apex (mm) Mean ± SD Min-Max Range	2.08 ± 0.21 1.81–2.41 0.60	1.40 ± 0.27 0.81–1.90 1.09	1.72 ± 0.41 0.81–2.41 1.60
Angular deviation (degrees) Mean ± SD Min-Max Range	4.63 ± 0.71 3.70–5.80 2.10	3.59 ± 0.97 1.60–4.80 3.20	4.11 ± 0.99 1.60–5.80 4.20

Linear deviations

The linear implant deviations in terms of three directions, mesiodistal, buccopalatal, and apicocoronal discrepancy at the implant platform and the implant apex, are shown in Tables 2 and 3, respectively. These values were shown in absolute numbers to show the discrepancy distance from the planned implant despite the direction of deviation. Due to the non-normal distribution of some data, Mann-Whitney U tests were used. Analyses showed that only the buccopalatal deviation value at the apex is statically different between groups (p = 0.001), with the 4-teeth group at 1.81 (1.47–2.06) mm and the 6-teeth group at 1.32 (1.05–1.45) mm.

Table 2

The overall linear deviations at the implant platform in each group.
Group	4-teeth (n = 14)	6-teeth (n = 14)	Overall (n = 28)
Mesiodisal (mm) Median (IQR) Min-Max Range	0.17 (0.10–0.21) 0.01–0.36 0.35	0.24 (0.14–0.29) 0.05–0.36 0.31	0.18 (0.13–0.27) 0.01–0.36 0.35
Buccopalatal (mm) Median (IQR) Min-Max Range	0.56 (0.46–0.93) 0.39–1.05 0.66	0.51 (0.31–0.66) 0.22–0.96 0.74	0.56 (0.41–0.80) 0.22–1.05 0.83
Coronoapical (mm) Median (IQR) Min-Max Range	0.31 (0.25–0.48) 0.09–0.79 0.70	0.25 (0.16–0.45) 0.12–0.58 0.46	0.27 (0.17–0.49) 0.09–0.79 0.70

Table 3

The linear deviations at the implant apex in each group
Group	4-teeth (n = 14)	6-teeth (n = 14)	Overall (n = 28)
Mesiodisal (mm) Mean ± SD Min-Max Range	0.45 (0.26–0.74) 0.16–1.34 1.18	0.62 (0.35–0.71) 0.06–1.05 0.99	0.55 (0.31–0.74) 0.06–1.34 1.28
Buccopalatal (mm) Mean ± SD Min-Max Range	1.81 (1.47–2.06) 1.25–2.11 0.86	1.32 (1.05–1.45) 0.39–1.65 1.26	1.46 (1.30–1.79) 0.39–2.11 1.72
Coronoapical (mm) Mean ± SD Min-Max Range	0.35 (0.25–0.53) 0.05–0.87 0.82	0.28 (0.20–0.46) 0.07–0.60 0.53	0.32 (0.23–0.52) 0.05–0.87 0.82

The 2D scatter plot (Fig. 5) displays the direction of linear deviations of implants at the platform and apex. In both groups, deviations at the implant platform and apex were mainly oriented towards the buccal. Discrepancies were observed in both the mesial and distal directions at the implant platform in both groups, whereas deviation at the implant apex was predominantly in the distal orientation.

This study examined how the number of teeth supporting surgical guides affects the accuracy of implant placement in a controlled laboratory setting. Accurate transferring of the preoperative implant plan to the surgical site is essential for appropriate restoration to ensure functional and esthetic outcomes, especially for immediate implant placement in the esthetic zone. A review by Tatakis et al.¹⁰ emphasized that properly stabilizing the surgical guide in the mouth is crucial for guided implant surgery's safe and predictable performance. In tooth-supported guides, stabilization of the surgical template can be influenced by the number and location of the remaining teeth. Both groups in the study showed an average deviation of 0.84 mm at the platform, 1.72 mm at the apex, and 4.11 degrees in angle for implant placement. However, there were significant differences between the two groups, with the six-teeth surgical guides being more accurate than the four-teeth support guides. This indicates that the number of supporting teeth can impact the success of immediate implant placement in the front upper teeth.

In a systematic review and meta-analysis conducted by Ali Tahmaseb et al. in 2018¹¹, it was found that the accuracy of surgical guide placement in partially edentulous cases resulted in a 3D platform and apex deviation of 0.90 mm [0.70-1.00 mm] and 1.20 mm [1.11–1.20 mm], respectively. The angular deviation was measured at 3.30 degrees [2.07–4.63 degrees]. Compared to this study, our research displayed higher deviation values, possibly due to implant placement in extraction sites, which presents a higher risk for deviation, where it is assumed that the implant will tend to deviate towards the side with less bone, which is less mechanical resistance. Despite this, both groups in the study had the result of implant positioning accuracy being clinically acceptable, with deviations measuring less than 2 mm across all variables. A 2 mm deviation is considered a safe margin when planning implant positions to avoid interference with adjacent anatomical structures.¹²

In the in vitro study by El Kholy et al.⁷, it was found that in cases of a single tooth gap, using short surgical guides covering four neighboring teeth resulted in an equivalent degree of accuracy to using full-arch surgical guides covering seven teeth. This finding suggested utilizing four teeth with two on each side of the single tooth gap for guide support to become the standard length of surgical guides. However, it is essential to note that this finding specifically applied to surgical guides for healing ridges. In the same study, implants placed in extraction sockets exhibited 50% higher mean platform and apex 3D deviation values and almost twice the mean angular deviation compared to implants placed in healed sites. Therefore, the results from our study indicate that increasing the number of teeth support from four teeth could improve the precision of immediate implant placement.

Deviation in the buccal direction can significantly impact buccal bone recession, affecting esthetic or functional outcomes. On the other hand, mesiodistal deviation can encroach upon nearby anatomical structures, such as the incisive nerve canal and adjacent roots. Therefore, assessing the risk of misalignment in mesiodistal and buccolingual directions is crucial. A study by Chen et al.¹³ indicated a preference for facial placement of implants. At the same time, other linear deviations showed no specific directional tendency, which aligns with the findings of this study. It is essential to note the challenge of maintaining a central and parallel position with the drill key during implant site preparation in socket sites. Even with the surgical guide, the drills and the implant tend to move toward the least resistant space, the extraction socket, in the facial direction. In the six-teeth group, the absolute value of buccopalatal deviation is statically lower compared with the four-teeth group. This indicated that increasing the support for surgical guides could result in more precise implant placement in an immediate implant with the extraction socket buccal from the planned implant position.

The present study shows the potential for further improving implant accuracy using a surgical guide, especially with increasing teeth support for the guides. While the study provides evidence for using surgical guides in immediate implant cases, it has limitations. Firstly, the models were made of acrylic resin, which may not fully replicate human bone densities and could lead to altered results when placing implants in human patients. Secondly, the study lacked a control group using an entire arch of remaining teeth (9 teeth) for comparison, which would have been the best possible support for the surgical guide in contrast to the 6-teeth group. Thirdly, in vitro studies do not replicate all clinical factors that may affect implant placement accuracy, as the guide is more stable due to the absence of the tongue and oral muscles, limited interocclusal distance, and the lack of saliva, blood, and patient movement.¹⁴ Nevertheless, the study provides valuable results for evaluating deviations in implant position, and the data may influence decision-making in clinical settings.

In conclusion, the results of this in vitro study indicated statistically significant differences in accuracy between the 6-teeth and 4-teeth support surgical guides. This suggests that the number of teeth providing guide support can influence the accuracy of immediate implant placement. Surgical guides supported by six teeth exhibited higher accuracy in placing implants for the maxillary central incisor than those supported by four teeth. Nevertheless, it is important to note that both groups achieved clinically acceptable outcomes regarding implant positioning accuracy, with deviations not exceeding 2 mm, a margin considered safe for implant placement in clinical practice.

CONFLICTS OF INTEREST

None declared

ACKNOWLEDGMENTS

We thank Straumann Implant Vietnam Trading Company Limited, Hoa My Dental Clinic, Ho Chi Minh City, Vietnam, and the Faculty of Odonto-Stomatology, University of Medicine and Pharmacy at Ho Chi Minh City, Vietnam, for supporting this study.

AUTHOR CONTRIBUTIONS

Conceptualization: Meo Nguyen, Truong Thien Tran

Data curation: Truong Thien Tran

Formal Analysis: Truong Thien Tran, Nam Cong-Nhat Huynh

Investigation:Truong Thien Tran, Huynh Kim Khanh Nguyen, Thien Nga Nguyen

Methodology: Meo Nguyen, Truong Thien Tran, Nam Cong-Nhat Huynh

Project Administration: Meo Nguyen, Truong Thien Tran

Writing – Original Draft: Truong Thien Tran, Huynh Kim Khanh Nguyen, Thien Nga Nguyen

Writing – Review & Editing: Nam Cong-Nhat Huynh, Truong Thien Tran. Meo Nguyen

Lou F, Rao P, Zhang M, Luo S, Lu S, Xiao J. Accuracy evaluation of partially guided and fully guided templates applied to implant surgery of anterior teeth: A randomized controlled trial. Clin Implant Dent Relat Res. 2021;23(1):117-30.
Evans CD, Chen ST. Esthetic outcomes of immediate implant placements. Clin Oral Implants Res. 2008;19(1):73-80.
Amorfini L, Migliorati M, Drago S, Silvestrini-Biavati A. Immediately Loaded Implants in Rehabilitation of the Maxilla: A Two-Year Randomized Clinical Trial of Guided Surgery versus Standard Procedure. Clin Implant Dent Relat Res. 2017;19(2):280-95.
Bhola M, Neely AL, Kolhatkar S. Immediate implant placement: clinical decisions, advantages, and disadvantages. J Prosthodont. 2008;17(7):576-81.
Buser D, Chappuis V, Belser UC, Chen S. Implant placement post extraction in esthetic single tooth sites: when immediate, when early, when late? Periodontol 2000. 2017;73(1):84-102.
Galante JM, Rubio NA. Digital Dental Implantology : From Treatment Planning to Guided Surgery. 1st 2021. ed: Springer International Publishing; 2021.
El Kholy K, Lazarin R, Janner SFM, Faerber K, Buser R, Buser D. Influence of surgical guide support and implant site location on accuracy of static Computer-Assisted Implant Surgery. Clin Oral Implants Res. 2019;30(11):1067-75.
Buser D, Martin W, Belser UC. Optimizing esthetics for implant restorations in the anterior maxilla: anatomic and surgical considerations. Int J Oral Maxillofac Implants. 2004;19 Suppl:43-61.
Resnik RR, Misch CE. Misch's Contemporary Implant Dentistry. 4th ed: Elsevier Health Sciences; 2021.
Tatakis DN, Chien HH, Parashis AO. Guided implant surgery risks and their prevention. Periodontol 2000. 2019;81(1):194-208.
Tahmaseb A, Wu V, Wismeijer D, Coucke W, Evans C. The accuracy of static computer-aided implant surgery: A systematic review and meta-analysis. Clin Oral Implants Res. 2018;29 Suppl 16:416-35.
Mistry A, Ucer C, Thompson JD, Khan RS, Karahmet E, Sher F. 3D Guided Dental Implant Placement: Impact on Surgical Accuracy and Collateral Damage to the Inferior Alveolar Nerve. Dent J (Basel). 2021;9(9).
Chen Z, Li J, Sinjab K, Mendonca G, Yu H, Wang HL. Accuracy of flapless immediate implant placement in anterior maxilla using computer-assisted versus freehand surgery: A cadaver study. Clin Oral Implants Res. 2018;29(12):1186-94.
Bover-Ramos F, Vina-Almunia J, Cervera-Ballester J, Penarrocha-Diago M, Garcia-Mira B. Accuracy of Implant Placement with Computer-Guided Surgery: A Systematic Review and Meta-Analysis Comparing Cadaver, Clinical, and In Vitro Studies. Int J Oral Maxillofac Implants. 2018;33(1):101-15.

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Influence of supporting teeth quantity of surgical guide on the accuracy of the immediate implant in the maxillary central incisor: An in vitro study

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Abstract

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INTRODUCTION

MATERIALS AND METHODS

Study design

Implant planning

Surgical guide fabrication

Surgical protocol

Outcome measurements

Statistical analysis

RESULTS

3D and angular deviations

Linear deviations

DISCUSSION

CONCLUSION

Declarations

References

Additional Declarations

Supplementary Files

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