|Year : 2019 | Volume
| Issue : 1 | Page : 12-19
Comparative evaluation of various methods of assessing residual alveolar ridge width prior to dental implant placement: An in vivo study
FB Sutaria, DN Shah, CJ Chauhan, JS Solanki, KA Bhatti
Department of Prosthodontics and Crown and Bridge and Oral Implantology, Ahmedabad Dental College and Hospital, Gandhinagar, Gujarat, India
|Date of Web Publication||17-Jun-2019|
Dr. F B Sutaria
Department of Prosthodontics, Crown and Bridge and Oral Implantology, Ahmedabad Dental College and Hospital, Gandhinagar, Gujarat - 382 115
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Purpose: There is always a slow but steady evolution occurred in dentistry, resulting in use of osseointegrated dental implants which became widely accepted procedure in the rehabilitation of edentulous spaces. Evaluation of the available alveolar bone dimensions is an important prerequisite for dental implant placement and successful outcome. Hence, this vivo study was designed to evaluate the accuracy of cone beam computed tomography (CBCT) and bone mapping for the diagnostic purpose.
Materials and Methods: A total of 27 partially edentulous sites in maxilla and/or mandibular arch were selected according to the mentioned criteria. The width of edentulous spaces was measured and compared by three methods: CBCT, bone mapping, and surgical exposure. Later, the obtained data were sent for statistical analysis to check the accuracy of methods for the assessment of residual alveolar ridge width prior to the dental implant placements.
Results: Normality check was done before finalizing statistical tests using Kolmogorov–Smirnov and Shapiro–Wilk test and non-parametric tests were applied for final analysis. Variables were compared using the Wilcoxon signed-Rank Test. Spearman's Rank correlation was obtained to check the relationship between variables. Throughout the result, significance level was fixed at 5% and if value of P < 0.05, it shows a significant result. For this study, P < 0.05 and statistically significant, which show that average measurements are significantly differ between the variables.
Conclusion: CBCT and ridge mapping measurements when compared individually with the gold standard, surgical open method, CBCT proved to be a highly accurate method detecting the residual alveolar ridge width in the dental implant treatment planning.
Keywords: Bone mapping, Cone-beam computed tomography, dental Implant, residual alveolar ridge width
|How to cite this article:|
Sutaria F B, Shah D N, Chauhan C J, Solanki J S, Bhatti K A. Comparative evaluation of various methods of assessing residual alveolar ridge width prior to dental implant placement: An in vivo study. J Dent Implant 2019;9:12-9
|How to cite this URL:|
Sutaria F B, Shah D N, Chauhan C J, Solanki J S, Bhatti K A. Comparative evaluation of various methods of assessing residual alveolar ridge width prior to dental implant placement: An in vivo study. J Dent Implant [serial online] 2019 [cited 2019 Dec 9];9:12-9. Available from: http://www.jdionline.org/text.asp?2019/9/1/12/260454
| Introduction|| |
The past decades of dental history show that humans have attempted to replace missing or diseased tissues with natural or synthetic substances. As time passed and civilization advanced with the development of biological, chemical, and physical sciences, an alternative attachment mechanism was discovered using an accidental finding by Prof. Per Ingvar Branemark et al., during 1950s–1960s.,, Now, dental implants have revolutionized contemporary dental treatment for the rehabilitation of missing dentition, replacing conventional therapies in the areas of complete and partial edentulism as well as for single tooth anodontia.,,,,
The goal of modern dentistry is to restore the patient to normal contour, function, comfort, esthetics, speech, and health. What makes implant dentistry unique is the improved ability to achieve this goal. However, careful diagnosis and treatment planning are must for favorable outcome. Treatment planning for implants includes a through radiographic and clinical examination. Evaluation of the dimensions of the available alveolar bone is an important prerequisite for dental implant placement. Bone evaluation limited to the use of panoramic and/or periapical radiographs may be insuficient because it only provides two-dimensional (2D) information about implant sites. Advanced digital radiographic techniques such as “computed tomography (CT)” have now become the mainstay for preimplantation assessment. The introduction of cone beam (CB) CT, in 1998, provided a new form of three dimensional (3D) evaluation. Several studies have shown that cone-beam computed tomography (CBCT) provides high quality, accurate cross-sectional images with relatively low dose exposure.
Before the introduction of CBCT, ridge mapping was one of the alternative method for assessing the residual alveolar ridge. Direct caliper measurements following surgical exposure of the bone are the most accurate and can be considered as the “gold standard” to assess the bucco-lingual alveolar ridge width. However, the flap reflection and measuring the residual alveolar ridge width after surgical exposure is not feasible or advisable just for diagnosis and treatment planning of the dental implant. Hence, this study is designed to evaluate and compare the accuracy of “CBCT and bone mapping” for the assessment of residual alveolar ridge before the dental implant placements.
| Materials and Methods|| |
Source of data
The present study was conducted among the volunteer patients coming to the Ahmedabad Dental College and Hospital. A total of 27 partially edentulous sites were considered for this study.
Healthy, nonpregnant patients with;
- Age range: 25–70 years
- Presence of partially edentulous ridge in maxilla and/or mandibular arch
- Presence of at least one periodontally healthy and stable tooth adjacent to the edentulous site to serve as an abutment
- A healing period ≥3 months following any extraction in the area of implant placement.
- Patients having any local or systemic contraindications for the implant placement
- Pregnant patients
- Freshly extracted socket
- Unhealthy abutment teeth.
Armamentariums [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
- Diagnostic instruments [Figure 1]
- Perforated impression trays [Figure 2]
- 2 ml disposable syringe-needle [Figure 3]
- Calibrated periodontal probe [Figure 4]
- Measuring scale [Figure 5]
- Surgical blade no. 15 [Figure 6]
- Periosteal elevator [Figure 7]
- Bone caliper [Figure 8].
Materials [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14]
- Irreversible hydrocolloid impression material [Figure 9]
- Type III dental stone [Figure 10]
- Acrylic teeth [Figure 11]
- Self-cure clear acrylic resin [Figure 12]
- Radio-opaque Gutta–percha material [Figure 13]
- Local anesthetic agent [Figure 14].
Twenty-seven partially edentulous sites in maxilla and/or mandibular arch were selected according to the mentioned criteria. The participants were asked to sign informed consent before oral examination with the help of diagnostic instruments [Figure 1]. The diagnostic impressions with perforated impression trays [Figure 2] by using irreversible hydrocolloid impression material (alginate impression material) [Figure 9] were made and diagnostic casts [Figure 15] were fabricated using dental stone material [Figure 10]. After this, 1/2/3 bucco-lingual pairs of consistent measurement points were marked on the partially edentulous site of the diagnostic cast at the level of 4 mm, 7 mm, and 10 mm, respectively, from the midline of residual alveolar ridge, according to available vestibular depth [Figure 16].
|Figure 15: Diagnostic cast made from the diagnostic alginate impression, showing partially edentulous site|
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|Figure 16: Marking of the bucco-lingual pairs of consistent measurements points from the midline of residual alveolar ridge|
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A clear acrylic [Figure 12] surgical stent was fabricated on diagnostic cast using acrylic tooth/teeth [Figure 11] for each subject. Later, the marked points on the diagnostic cast were transferred on the surgical stent and the holes were prepared with the help of 1 mm diameter bur at the same marked points; centrally and bucco-lingually. Then the holes in the surgical stent were filled with radio-opaque Gutta-percha material [Figure 13] before taking CBCT [Figure 17]a, [Figure 17]b, [Figure 17]c, which provides radio-opaque landmarks indicating the locations for comparative radiographic ridge width measurements in CBCT [Figure 18].
|Figure 17: (a-c) A clear acrylic surgical stent was fabricated and the marked points on the diagnostic cast were transferred on the surgical stent. The holes were prepared at the same marked points; centrally and bucco-lingually and filled with radio-opaque Gutta-percha material before taking cone-beam computed tomography|
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|Figure 18: Radio-opaque landmarks indicating the locations for comparative radiographic ridge width measurements in cone-beam computed tomography|
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Later following local anesthesia, [Figure 14] using 2 ml Disposable syringe-needle [Figure 3] the surgical stent was placed in the area to be measured, after removing Gutta-percha from the prepared holes [Figure 19]. The tip of the calibrated periodontal probe (University of North Carolina/William's probe) [Figure 4] was inserted into guiding holes, penetrating through the soft tissue until there was contact with bone and the soft-tissue thickness was measured [Figure 20]a, [Figure 20]b, [Figure 20]c.
|Figure 19: The surgical stent was placed in the area to be measured, after removing Gutta-percha from the prepared holes|
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|Figure 20: (a-c) The tip of the calibrated periodontal probe was inserted into guiding holes penetrating through the soft tissue to create bleeding points and later the soft-tissue thickness was measured until there was contact with bone|
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The edentulous area of the diagnostic cast was then sectioned perpendicular to the alveolar ridge at the level of marked points. The clinically measured tissue thickness was mapped out at the same marked points on the sectioned diagnostic cast using pencil, and the bone width was measured with scale [Figure 5] by drawing the straight line connecting the buccal and lingual points of the same level [Figure 21].
|Figure 21: The clinically measured tissue thickness was mapped out at the same marked points on the sectioned diagnostic cast using pencil and the bone width was measured with scale by drawing the straight line connecting the buccal and lingual points of the same level|
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After these both techniques, surgical flap reflection with surgical blade [Figure 6] and periosteal elevator[Figure 7] had done at the time of implant placement and residual alveolar ridge width was measured directly on the exposed bone at the various location of the prepared guiding holes using same surgical stent with the help of bone caliper [Figure 8] (GDC). Later the obtained data, including the bone width measurements according to CBCT, bone mapping and surgical exposure was sent for statistical analysis [Figure 22].
|Figure 22: (a-c) Surgical flap reflection had done at the time of implant placement and residual alveolar ridge width was measured directly on the exposed bone through the prepared guiding holes using same surgical stent with the help of bone calliper|
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| Results|| |
An in vivo study was conducted to comparatively evaluate the accuracy of CBCT and bone mapping for the assessment of residual alveolar ridge width before dental implant placement for 27 partially edentulous sites.
According to null hypothesis the average residual alveolar ridge width measurements are same for the all three groups, CBCT, bone mapping, and surgical open method.
Normality check was done before finalizing statistical tests using Kolmogorov–Smirnov and Shapiro–Wilk test and according to mentioned tests, non-parametric tests were applied for final analysis. Variables were compared using the Wilcoxon Signed–Rank test. Spearman's Rank correlation was obtained to check the relationship between variables. Throughout result significance level was fixed at 5% and if P < 0.05, it shows significant result.
[Table 1] shows the normality check with descriptive statistics including mean, median, Standard deviation, Inter quartile range, Skewness, Kurtosis values according to data obtained.
According to [Table 2], P > 0.05 and nonsignificant, which favors the null hypothesis that average measurements are same between surgical exposure and CBCT, which shows that CBCT is better than bone mapping.
According to [Table 3], P < 0.05 and statistically significant, which rejects the null hypothesis and shows that average measurements are significantly differ between surgical open method and bone mapping. CBCT measurement is almost same as surgical open method. Thus, out of CBCT and bone mapping methods, CBCT is significantly better [Graph 1], [Graph 2], [Graph 3].
| Discussion|| |
In the advanced era of dental implantology even experienced implant surgeons are sometimes misled by the apparent bucco-lingual dimension of the maxillary or mandibular ridges. After exposure of the bone, the reality of the resorbed ridge becomes frustratingly apparent. This unexpected lack of dimension can result in a sudden change in the treatment program, which was not previously discussed with the patient. In some situations, the treatment must be abandoned completely because of a lack of available ridge bone. Thus, placement of dental implants requires meticulous planning and careful surgical procedures.
Diagnostic radiography is essential for implants in pre-operative, intraoperative, and postoperative assessment by use of a variety of imaging techniques. In the past, periapical radiographs, occlusal radiograph along with panoramic images were used as the sole determinants of implant diagnosis and treatment planning. Hence, these radiographic modalities provide a 2D representation of 3D structures, the advanced use of CT, CBCT with 3D information is cardinal for the implantologist before placing dental implants.
Since the introduction of CT, ridge mapping has become a less popular method for the assessment of patients requiring implant therapy. However, ridge mapping might still be useful for selected cases because it can provide instant information at chairside and has the advantage of being simple to use, and it avoids exposure to radiation for the patient.
In the present study, the reliability of the other two methods, ridge mapping, and CBCT image, was evaluated by comparison with the open surgical method and direct caliper measurements following surgical exposure of the bone would seem to be the most accurate measuring method and could be considered as the “Standard group.”According to the results, the basic data obtained in this study shows a mean difference of 0.06 mm in between CBCT and surgical open method and 0.18 mm in between bone mapping and surgical open method. Thus, result shows that average mean measurements are significantly differs between surgical open method and bone mapping. CBCT measurement is almost the same as surgical open method.
This result differs with a study done by Wilson, who concluded that ridge mapping is a simple and effective method of diagnostically measuring alveolar thickness before surgery, but not comparable to a full surgical flap reflection. On another side, the findings of Allen and Smith supports the result of this study which indicates that ridge-mapping alone is not sufficient enough to precisely predict the bone availability for implantation in the anterior maxilla. Veyre-Goulet also concluded that although cadaver bone density may not correspond to the density of vital bone, CBCT images are reliable to define the bone volume of the posterior maxilla to plan the implant axis.
This study finding also differs to some extent with those obtained by Chen et al. who found statistically significant equivalences between measurements of ridge mapping and surgical open method, but not with those from CBCT and surgical open method. Following our analysis, result favors the study by Luk et al. who concluded that bone ridge measurements obtained on CBCT and the ridge mapping were significantly different with a mean difference around 0.4 mm. Ridge mapping is indicated only for mild or moderately resorbed cases with implants planned coronal to the alveolar sulcus. The result of this study also matches the study done by Castro-Ruiz et al., which explained that both methods provide valid measurements and CBCT was recommended when the bone ridge width and height were less than ideal for conventional dental implant treatment.
Thus data obtained in this study shows the usefulness and accuracy of CBCT for pre-surgical planning of dental implants, while explains the use of ridge mapping technique as a simple and cost-effective tool for bucco-lingual residual alveolar ridge width measurements in ideal cases. As this study was done by a single observer, moreover population chosen in the study was based on convenience sampling, and the accuracy of dental materials used in the study can affect the data, further similar researches on different and big size samples are needed to confirm the obtained results.
| Conclusion|| |
Within the limitations of this study, it was concluded that CBCT and ridge mapping measurements when compared individually with the gold standard-surgical open method, CBCT proved to be a highly specific and sensitive method detecting the residual alveolar ridge width in the treatment planning of dental implants. Similarly, we believe that ridge mapping is a useful method when supplemented by conventional radiographic methods that do not involve irradiation to the patient. It is of low cost and gives immediate results for alveolar ridge width. Whereas it is suggested to use CBCT technique in situations where the alveolar ridges are resorbed, there is the presence of maxillary anterior ridge concavities, there are high lingual frenum areas, vestibular depth is inadequate, and ridge mapping is not feasible.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14], [Figure 15], [Figure 16], [Figure 17], [Figure 18], [Figure 19], [Figure 20], [Figure 21], [Figure 22]
[Table 1], [Table 2], [Table 3]