Comparative Evaluation of Different Alveolar Ridge Width Measurement Techniques in Dental Implant Treatment Planning: An in Vivo Observational Non-Interventional Study

Abstract

In todays era dental implant has become the dependable therapeutic treatment for the replacement of missing teeth. The success of dental implants depends not only on osteointegration of the implant but also on the surrounding hard and soft tissue. Presurgical evaluation of alveolar ridge width and height is of paramount important for implant placement. There are several methods to evaluate the alveolar ridge width and height such as ridge mapping and CBCT. This study included 30 sites from 8 patients in the age ranging from 30 to 65 years. A stent was prepared and the width of the alveolar ridge was estimated employing the following techniques: Group I: Measurement of alveolar ridge width on cone-beam computed tomography (CBCT) method, group II: Measurement of alveolar ridge width by ridge mapping technique, group III: Measurement of alveolar ridge width by surgical exposure. The minimum value for ridge mapping with caliper is 2 and maximum value is 9 with mean 4.5667 ± 1.63335 with standard error 0.29821. The minimum value for Cone beam computed tomography (CBCT) is 1.80 and maximum value is 9.30 with mean 4.6233 ± 1.67119 with standard error 0.30512. The minimum value for direct intrasurgical measurement with caliper is 2 and maximum value is 9 with mean 4.2000 ± 1.58441 with standard error 0.28927. Cone beam computed tomography could also be used to measure the ridge width accurately. Apart from measurement of alveolar ridge dimensions it had multiple other uses and thus can be advised as per requirement of the clinician.

Introduction

The most recent and widely preferred options to replace missing teeth are the dental implants. They maintain bone shape and function and transmit the masticatory forces to the bone like the natural teeth [1]. The success of dental implants is defined by osseointegration of the dental implant and harmonious and natural blending of the restoration with the surrounding tissues and dentition. Preoperative assessment is essential to identify the biological, functional, and biomechanical parameters as well as the potential problems that may arise after placement of implant. Such influencing factors are the amount of available alveolar bone, morphologic type of the soft tissue; correct positioning of the implant in all three dimensions, the provisional phase, the design and material of the implant abutment, and material and design of the definitive crown [2].

Dental rehabilitation with implants has been widely accepted by doctors and patients in recent decades due to its reliable, functional and aesthetic results. In long-term clinical application, the survival rate for dental implants is over 90% [3]. The success of dental implants is related to the quality and quantity of the underlying bone, implant design and surgical technique. Various endogenous and exogenous factors determine success of dental implants. Bone quality and quantity are endogenous factors, and implant diameter and length are exogenous factors. These factors significantly influence implant success rates. Bone quality varies in different areas of the jaw bone. Mandibles are usually more densely corticated than maxillae; and both jaws tend to decrease in their cortical thickness but increase in their trabecular porosity as they move posteriorly. Bone quality and quantity are often more compromised in maxillary than in mandibular sites in implant dentistry [4].

Assessment of alveolar bone dimension is an important prerequisite for implant planning. Various two-dimensional and three-dimensional methods are being used currently to assess the alveolar bone dimensions ranging from the ancient direct intra-operative measurements, ridge mapping, periapical radiographs and conventional panoramic radiographs to the modern Computed Tomography, Cone Beam Computed Tomography and 3-D Tomography [1, 2].

The alveolar process is affected by various environmental and physiologic factors that influence its ability to function and maintain its integrity. Patients often present for implant planning after tooth loss and alveolar ridge resorption. A deficiency in the horizontal dimension of bone may be minimal, such as a dehiscence or fenestration of an implant surface, or it may be more significant such that the implant would have more than one axial surface exposed while having some bone along the entire vertical length. The physiology and healing patterns of the edentulous ridge after a tooth was extracted were often neglected or not dealt with properly before implant therapy came into practice. However, today, implant placement in severe cases of alveolar ridge resorption is a well-understood and recognized challenge and it significantly impacts the success of implant therapy. The various causes of alveolar bone loss could be congenital, pathological, result of trauma, chronic/acute infection, or a consequence of periodontal disease. The most widely experienced scenario after extraction is clinical deficiency in the ridge, leading to the loss of mechanical function. Approximately 25% of the bone volume is reported to be lost in the first year after tooth extraction. Over time, this deterioration may progress and has been reported to be responsible for a 40–60% loss of alveolar volume during the first 3 years after a tooth has been lost. The resulting ridge deficiency is primarily the result of the gradual loss of the horizontal dimension accompanied by a rapid loss of bone height [5–8].

The apparent bucco-lingual dimension of the maxillary or mandibular ridges can be misleading even for the experienced implant surgeons. A resorbed ridge may be revealed on exposure of the bone at the time of implant placement. This unexpected lack of dimension can result in a sudden change in treatment plan or sometimes the treatment must be abandoned completely because of lack of available ridge bone [9].

Alveolar ridge width can be assessed before reflecting the flap, before the actual implant surgical procedure. There are various diagnostic modalities out of which ridge mapping using a caliper is one such method. This procedure is performed chair-side under local anesthesia and provides instant information. The pointed tips of the instrument penetrate buccal and lingual soft tissue and reach upto the bone to measure the bucco-lingual width of the underlying bone. Prior to reflection of a mucoperiosteal flap, a series of measurements of the proposed implant site can be made [10]. The technique has been advocated by Wilson (1989) [9] and Traxler et al. (1992), have suggested it as reliable method to evaluate the bone availability for dental implant surgery [10]. Ridge mapping needs to be compared to what would seem to be the most accurate measurement which is direct calliper measurements following surgical exposure of the bone [10, 11].

The bucco-lingual ridge width can be evaluated by three dimensional radiographic techniques such as computerized tomography (CT) and Cone Beam Computed Tomography (CBCT). Advanced digital radiographic techniques such as Cone Beam Computed Tomography (CBCT) have now become an important aid for assessment of alveolar ridge dimensions prior to implant placement. Cone Beam Computed Tomography (CBCT) not only provides alveolar ridge dimensions but also has the advantage of having a superior spatial resolution compatible with dental implants simulation programs, which becomes a highly important advantage in comparison with all the other techniques. The advantages of Cone Beam Computed Tomography (CBCT) include high image quality, compact size, fast scan time, low radiation dose and ease of accessibility. Another clinically valuable aspect of Cone Beam Computed Tomography (CBCT) is the sophisticated software which can be used to create different image port folios for each patient. All these variables make Cone Beam Computed Tomography (CBCT) a valued technique in the emerging field of implantology [12].

This study intends to determine and compare the accuracy of ridge mapping and Cone Beam Computed Tomography (CBCT) to direct intrasurgical measurements in alveolar ridge width measurement and to determine the suitable diagnostic modality in pre-surgical planning of dental implants.

Materials and Methods

This study was carried out after approval from the Institutional Ethical Committee. Written, informed consent was obtained from participating patients. Patients reporting to the OPD of Department of Periodontology at this hospital and willing to choose implant as an option for replacing missing teeth, were taken for this study, subject to fulfillment of following criteria:

Inclusion Criteria

1. Patients selected for implant placement with a minimum of one edentulous site.

2. A healing period of ≥ 3 months following any extraction in the area of implant placement.

3. Systemically healthy patients.

4. Age ≥ 18 years.

Exclusion Criteria

1. Patients with systemic illness that contraindicates placement of implants or/ affects outcome of therapy.

2. Pregnant and lactating women.

3. Patients who do not demonstrate motivation or who are unwilling for treatment.

30 sites were evaluated from 8 patients from age range 30 to 65 years. 11 sites of alveolar ridge width measurement were recorded from 3 male patients and 19 sites were recorded from 5 female patients. Patients reporting to the OPD of Department of Periodontology at this hospital were taken up for the study. Patients were explained the various treatment modalities for replacement of missing teeth and those who were willing to choose implant as an option for replacing missing teeth, were taken for this study. A detailed case history was recorded. A standard proforma consisting of the following data: name of the patient, age, sex, occupation, past dental history, medical history and personal history. Clinical examination included extra oral examination: facial form, profile, symmetry. Soft tissue examination: mucosa, vestibule, gingiva and pockets. Edentulous area span and edentulous ridge form was evaluated. Hard tissue examination included number of teeth present and missing teeth. Phase 1 periodontal therapy was performed in the patients. Complete supragingival scaling and root planing was performed.

Fabrication of the Stent

Alginate impressions were made using metal stock trays. Study models were fabricated using orthodontic stone class III. Vacuum formed stent was then fabricated using 0.5 mm biostar sheets using the biostar machine. Biostar machine is a versatile pressure moulding machine for all applications in dental pressure moulding with scan technology and 6.0 bar working pressure. The unique thermally controlled infrared heater reaches working temperature in one second. All important data such as temperature, heating and cooling times are programmed by reading the scanner or entering the corresponding code. Once the stent is obtained the guide holes were made in it.

2 points were marked, one on the buccal and one on the lingual/ palatal surfaces of the stent at 7 mm each from the summit of the alveolar soft tissue. Using a round diamond bur of 2 mm, holes were drilled into the stent at the 7 mm points. Gutta percha was heated and condensed in these points to act as a radio opaque marker on the Cone Beam Computed Tomography.

Assessing Ridge Width on the Cone Beam Computed Tomography

The stent was placed in the patient’s mouth and Cone Beam Computed Tomography images were recorded. The CS 9300 System was used. The device was operated at 60–90 kV with an exposure time ranging from 12 to 28 s (+/-10%), voxel size 90 to 180 μm, field of view (cm) 5 × 5, 10 × 5 and 10 × 10, depending on the size of the area to be analyzed (maxilla, mandible, or both). The alveolar ridge width was recorded as the distance between the outermost points of the cortical bone on the line passing through the two gutta percha points on the buccal and lingual/ palatal aspects of the site.

Assessing Ridge Width Before Flap Reflection

Following administration of local anesthesia, 2% lignocaine hydrochloride with 1:80,000 adrenaline, the stent was placed in the patient’s mouth and alveolar ridge width was measured using tissue piercing ridge mapping caliper. The tips of the ridge mapping caliper were pierced through the guide holes till they contacted the bone. This was the measurement obtained prior to flap reflection.

Direct Caliper Measurements After Flap Reflection

At the time of surgery, crestal incisions were given and full thickness mucoperiosteal flap was reflected on buccal and lingual sides. The alveolar ridge was exposed. The stent was then placed in the patient’s mouth and direct measurement of alveolar ridge width was done with the same caliper by passing the tips of the caliper through the guide holes. This was the actual ridge width recorded. All these measurements were done by a single examiner. All the patients taken up for the study underwent implant therapy as planned after completion of the study.

The three measurements obtained were then tabulated for comparison. Descriptive statistics were expressed as mean ± standard deviation (SD) for each group. Frequency distribution and percentage were calculated for gender distribution. Two groups (CBCT vs. direct intrasurgical measurement) and (ridge mapping vs. direct intrasurgical measurement) were compared for measurements by Independent ‘t’ test.

Results

This study was conducted to determine the accurate diagnostic modality for determining the alveolar ridge width prior to implant placement.

30 sites were evaluated for measurement of alveolar ridge width comparing ridge mapping caliper and cone beam computed tomography to the direct intrasurgical measurements using caliper. These 30 sites were evaluated from 8 patients from age range 30 to 65 years. 11 sites of alveolar ridge width measurement were recorded from 3 male patients and 19 sites were recorded from 5 female patients.The mean age among patients is 45.07 ± 11.277.

11 (36.7%) sites belonged to male patients while 19 (63.3%) sites belonged to female patients.

The minimum value for ridge mapping with caliper is 2 and maximum value is 9 with mean 4.5667 ± 1.63335 with standard error 0.29821. The minimum value for Cone beam computed tomography (CBCT) is 1.80 and maximum value is 9.30 with mean 4.6233 ± 1.67119 with standard error 0.30512.

The minimum value for direct intrasurgical measurement with caliper is 2 and maximum value is 9 with mean 4.2000 ± 1.58441 with standard error 0.28927 (Table 1).

Table 1.

Descriptive Statistics for measurement by three Methods

GROUP	N	Minimum	Maximum	Mean		Std. Deviation
	Statistic	Statistic	Statistic	Statistic	Std. Error	Statistic
RIDGE MAPPING	30	2.00	9.00	4.5667	0.29821	1.63335
CBCT	30	1.80	9.30	4.6233	0.30512	1.67119
DIRECT INTRASURGICAL MEASUREMENT	30	2.00	9.00	4.2000	0.28927	1.58441

The direct intrasurgical measurement is the actual ridge width and is considered as the “gold standard”. The other two methods, ridge mapping using caliper and cone beam computed tomography were compared for measuring the alveolar ridge width. It was seen that the ridge mapping caliper measurements are more close to direct intrasurgical measurements than the cone beam computed tomography readings.

The mean difference in group A / ridge mapping (4.5667 ± 1.63335) and group C/ direct intrasurgical measurement (4.2 ± 1.58441) is 0.36667 which was found statistically insignificant with p = 0.381. (Table 2).

Table 2.

Comparing measurements RIDGE MAPPING and DIRECT INTRASURGICAL MEASUREMENT (DIM) by Independent ‘t’ Test

Ridge (n = 30)	Ridge Mapping (Mean ± SD)	DIM (Mean ± SD)	Mean difference	t value	df	p value	Confidence Interval CI (95% Lower Upper
Measurements	4.5667 ± 1.63335	4.2000 ± 1.58441	0.36667	0.883	58	0.381*	− 0.46496	1.19830

This implies that ridge mapping using caliper can be a useful diagnostic technique prior to implant placement, to measure the ridge width, as no statistically significant differences are obtained when compared to the actual ridge width after surgical exposure.

The mean difference in group B/ CBCT (4.6233 ± 1.67119) and group C/ direct intrasurgical measurement (4.2 ± 1.58441) is 0.42333 which was found statistically insignificant with p = 0.318. (Table 3)

Table 3.

Comparing measurements CBCT and DIRECT INTRASURGICAL MEASUREMENT (DIM) by Independent ‘t’ Test

Ridge (n = 30)	CBCT (Mean ± SD)	DIM (Mean ± SD)	Mean difference	t value	df	p value	Confidence Interval CI (95% Lower Upper
Measurements	4.6233 ± 1.67119	4.2000 ± 1.58441	0.42333	1.007	58	0.318*	− 0.41828	1.26495

This implies that cone beam computed tomography can be a useful diagnostic technique prior to implant placement, to measure the ridge width, as no statistically significant differences are obtained when compared to the actual ridge width after surgical exposure.

Discussion

Careful planning and diagnosis result in a more predictable outcome in all phases of clinical dentistry. The alveolar process develops in conjunction with the eruption of the teeth. It is a tooth dependant tissue. The tooth is anchored via the bundle bone into the jaws in which the periodontal ligament fibres invest. The volume as well as the shape of the alveolar process is determined by the form of the teeth, their axis of eruption and eventual inclination. The alveolar process undergoes atrophy once the teeth are extracted. The bundle bone at the site obviously will lose its function and disappear [13].

Tooth extraction is one of the most common dental procedures. Generally, the extraction socket heals uneventfully. However, even with uneventful healing, the alveolar defect that results as a consequence of tooth removal will only become partially restored. Concurrent with bone growth into the socket, there is also well-documented, resorption of the alveolar ridges. The greatest amount of bone loss is in the horizontal dimension and occurs mainly on the facial aspect of the ridge. There is also loss of vertical ridge height, which has been described to be most pronounced on the buccal aspect. This resorption process results in a narrower and shorter ridge and the effect of this resorptive pattern is the relocation of the ridge to a more palatal/lingual position [13–15].

The defect resulting from the loss of a tooth may be complicated by previous bone loss due to periodontal disease, endodontic lesions, or a traumatic episode. The situation becomes even more compromised when the alveolus has lost walls or height. Loss of alveolar bone may have occurred before tooth extraction because of periodontal disease, periapical pathology, or trauma to teeth and bone. The size of the residual ridge is reduced most rapidly in the first 6 months, but bone resorption activity in the residual ridge continues throughout life at a slower rate resulting in the removal of large amounts of jaw structure. Morphologic changes in extraction sockets have been described by cephalometric measurements, study cast measurement, radiographic analysis and direct measurements of the ridge following surgical re-entry procedures [10].

Damage of the bone tissue during tooth removal may also result in bone loss. However, within the past decade, as aesthetics have received more emphasis with treatment planning, resorption of the alveolar ridge following tooth extraction, especially in the anterior region has become a significant problem. After tooth removal, the clinician faces the challenge of creating a prosthetic restoration that blends with the adjacent natural dentition. Sufficient alveolar bone volume and favourable architecture of the alveolar ridge are essential to obtain optimal functional and aesthetic prosthetic reconstructions.

Cases with good bone volume, bone height, and tissue thickness can be predictable in terms of achieving good esthetic and functional results. Patients with less-than-ideal tissue qualities pose difficult challenges for the restorative and surgical team in achieving optimum results. Many diagnostic modalities have been reported for assessment of the ridge dimensions. Various two-dimensional and three-dimensional methods are being used currently to assess the alveolar bone dimensions ranging from the ancient direct intra-operative measurements, ridge mapping, periapical radiographs and conventional panoramic radiographs to the modern Computed Tomography, Cone Beam Computed Tomography and 3-D Tomography. However, there are not sufficient studies to determine the accuracy of each of this method, hence, this study was conducted to determine and compare the accuracy of ridge mapping and Cone Beam Computed Tomography (CBCT) to direct intrasurgical alveolar ridge width measurement and to determine the better diagnostic modality in pre-surgical planning of dental implants.

Conventional radiography such as panoramic and periapical radiographs do not provide cross-sectional information, and are therefore insufficient for implant site evaluation. Tomographic images are useful for assessing information on ridge measurements three-dimensionally and thus considered essential for the surgical planning of implant placement. CBCT provides a valuable tool for evaluating craniofacial region. Effective radiation dose from a scan of maxillofacial volume is significantly lower than medical CT and is in the range of conventional dental radiographies. The linear measurement of distances is often used in presurgical implant planning for the determination of the exact amount of alveolar bone (height and width) and consequently the size of the dental implants. The image data is acquired from a single 360 rotation scan around the patient. Image reconstruction provides multiplanar images.

Shokri [16] described CBCT as highly accurate and reproducible in linear measurements in the different areas of the maxillofacial region. Cone Beam Computed Tomography can provide submillimeter spatial resolution for images of the craniofacial complex, with scanning time comparable to panoramic radiography. The cone-beam technique uses rotational scanning of an X-ray source, reciprocating an X-ray detector around the patient head. CT/CBCT images are displayed as a matrix of individual blocks called voxels (volume element). CBCT can perform imaging of maxillofacial structures with different voxel sizes. The voxel size in our CBCT was 90–180 µm which is smaller than that achieved with conventional CT units. Smaller voxel size provides better image resolution. CBCT software provide tools to measure distances, angles, zoom, invert the gray scale, adjust contrast, and gamma changes.

Pinsky [17] Van Assche N et al. [18] and Loubele M [14] have suggested that measurements using cone beam computed tomography are accurate for determining linear measurements. These studies support our findings where we have obtained accurate measurements of the bucco lingual dimensions of the ridge using cone beam computed tomography.

Wilson [9] first used ridge mapping calliper for measuring ridge width. He described it as a measurement procedure to ensure that the diameter of an endosseous screw implant does not exceed the dimensions of available bone. The primary aim of implant therapy is the long term success of the dental implants. To achieve this, it is essential for the initial evaluation of the dimensions of the resorbing alveolar process to be absolutely accurate. The mucosal contour can mask the actual dimension of the alveolar ridge and thus might create a problem in estimating the actual thickness of the underlying bone. The Wilson Bone Caliper made possible a reliable evaluation procedure at the initial stage of treatment planning by performing ridge mapping. Similarly after Wilson, Davis and Traxler came up with new designs for the calliper to be used for measuring the ridge width [9, 19]. Thus in our study we used ridge mapping calliper as one of the diagnostic modality for measuring of the ridge width.

This study was an in vivo observational non-interventional study. This study was carried out by one examiner to avoid inter-examiner error. In this study the mean difference in group A / ridge mapping (4.5667 ± 1.63335) and group C/ direct intrasurgical measurement (4.2 ± 1.58441) is 0.36667 which was found statistically insignificant with p = 0.381. The mean difference in group B/ CBCT (4.6233 ± 1.67119) and group C/ direct intrasurgical measurement (4.2 ± 1.58441) is 0.42333 which was found statistically insignificant with p = 0.318.

Castro-Ruiz et al. [11] showed similar results with no statistically significant differences obtained with CBCT and ridge mapping measurements. CBCT was recommended when the bone ridge width and height were in the less than ideal for conventional dental implant placement. Though ridge mapping were less accurate compared to CBCT, it can be used due to its ease of use and low cost. However, in our study ridge mapping was found more accurate than CBCT but the results of both studies are statistically insignificant.G S Amarnath et al. [20] conducted a study on completely edentulous mandibles comparing cone beam computed tomography, orthopantomography and direct ridge mapping using digital vernier calliper. They have found that sizable portion of the CBCT measurements with respect to width showed slight overestimation when compared to direct measurements and no statistically significant differences, similar to that found in our study. However, the digital vernier calliper used in their study cannot be used for intraoral measurements in humans.

Chen et al. [10], have showed dissimilar results than our study. They found statistically significant differences in measurement using cone beam computed tomography when compared to direct intrasurgical measurement. This difference was due to difficulty in locating cortical borders and certain points that were located in the soft tissues. We did not face this problem as the points were located 7 mm from the crest of the ridge and all the points corresponded with the alveolar bone. No points were in the soft tissues. In their study, there were 6 radio-opaque points and it was difficult to obtain a single cross section passing through all points. In our study, there were only two points and hence a single bucco-lingual cross section passing through both points was easily located.

Luk et al. [21] conducted a study to compare the relative accuracy of the ridge-mapping against that of standard Computed Tomography (CT). The vacuum formed templates with reference points were used for ridge mapping. They found statistically significant differences in the measurements which are different from results obtained from our study. Measurements of the alveolar bone dimension using the ridge mapping method were found different from CT scanning, with a mean difference of about 0.4 mm. They concluded that CBCT images showed significantly more accurate results in comparison with the direct caliper measurements and that CBCT proved more reliable than CT regarding ridge bone measurements for dental implant planning. However, the drawback of this study was that they did not compare these measurements to direct intraoperative measurements which were overcome in our study.

According to Allen F, Smith DG., [22] there were statistically significant measurement differences between pre- and intra-operative measurements using ridge mapping. The preoperative values obtained from ridge mapping over estimated the ridge width. This could be due to the caliper tip not completely penetrating the overlying mucosa down to the bone. Such a problem can arise if if the overlying mucosa is thick. We found similar results in certain cases where the preoperative values measured by the caliper were larger than the actual ridge width found intraoperatively. However our results were statistically insignificant.

Cortes ARG [23] conducted a similar study comparing cone beam computed tomography to the direct intrasurgical measurements using ridge mapping caliper. Their findings support our study wherein positive deviations, that is, large values for tomographic images as compared to direct measurements were more frequently found. However these were statistically insignificant differences similar to our study and hence cone beam computed tomography is a reliable method.

Perez LA, Sharon L [24] conducted a study on human cadavers and compared the linear tomography and ridge mapping for determination of edentulous ridge dimensions. In their study they found that ridge mapping underestimated the ridge width and the possible reason for this could be application of excessive pressure leading to penetration of the cortical bone which could be worsened by repeated measurements. In our study we did not get any values lower than the actual ridge width using ridge mapping caliper as a single measurement was taken and values obtained were accurate estimation of ridge width when compared to the actual width.

The findings obtained by Chugh et al. [25] are in support of our study where they found that there is no significant difference in the measurements obtained by direct surgical exposure technique, ridge‑mapping technique, and CBCT technique.

From the findings of our study both ridge mapping calliper and CBCT provide useful diagnostic information in alveolar ridge width measurement prior to implant planning. The ridge mapping techniques is a useful chairside diagnostic method to evaluate the ridge morphology. It is easy to use and avoids the patient exposure to radiation. Use of ridge‑mapping technique along with panoramic and intraoral radiographs may be adequate in cases where the pattern of resorption appears more regular and where mucosa is of more even thickness.

Even though our study shows that both ridge mapping caliper and cone beam computed tomography are beneficial for determining the ridge width, this study has certain limitations. The use of ridge mapping technique prior to implant placement involved an invasive procedure which required administration of local anaesthetic prior to actual surgical procedure. As the ridge width was measured at only one point the actual morphology of the ridges was not determined. This is because there is variable ridge width throughout the length of the ridge. This will require further studies measuring ridge width at multiple points. The use of cone beam computed tomography also had certain limitations. The cost of the diagnostic modality and patient exposure to radiation are the drawbacks of this technique and hence its use should be recommended only when required. It is suggested to use CBCT scan technique in situations where the alveolar ridges are resorbed, there is presence of maxillary anterior ridge concavities, vestibular depth is inadequate, and ridge mapping is not feasible. This decision is based upon the experience and skill of the clinician. Since CBCT image quality on patients is decreased by the presence of soft tissue and possible patient movement during scanning, further studies are indicated to confirm the present results. Since the sample size of our study was relatively small, further studies are recommended with data of larger size.

With the use of computers, there have been many advances in the field of dentistry. Many computer guided implant techniques have been developed. There are number of clinical computer applications developed to allow clinicians to obtain 3D models and plan virtual situations. These programs are increasingly used as tools for implant diagnosis, planning, and treatment execution. In addition to their use with imaging techniques, interactive software programs are used to construct surgical templates for transferring the planned treatment to the patient’s mouth [26]. The precise implant placement offered through the application of modern technologies to dentistry has allowed immediate loading with prefabricated final restorations. For example, the recently introduced “Immediate Smile” treatment protocol allows the simultaneous placement of endosseous implants and a CAD/CAM-guided, immediately loaded, definitive prosthesis [27]. Its viability is supported by its accuracy, which allows the virtually planned 3D model to be transferred to the surgical template, the implants to be placed, and the prosthesis to be attached immediately after abutment connection. Three tools for computer-guided implant placement have been reported in the literature: robots, navigation, and CAD/CAM-generated stereolithographic surgical guides (SSGs). Robots are accurate tools to transfer the treatment plan to patients; however, their high cost and low availability limit their use [28]. Navigation systems permit improved precision of insertion in terms of the position, angulation, and depth of implant placement compared to conventional freehand placement [29]. Protocols using a navigation system reportedly result in similar accuracies compared to protocols using CAD/CAM-developed SSGs. The main benefit of CAD/CAM-guided dental implant planning and placement is that it allows thorough preoperative diagnostics and a more predictable implantation procedure. Given the limited data, relatively short observation periods, and lack of randomized controlled trials available in the literature, prospective clinical studies with long-term follow-ups need to be performed regarding the use of these newer technologies.

Thus from the above discussion it could be deduced that ridge mapping as well as cone beam computed tomography can be used for assessment of alveolar ridge width prior to placement of dental implants. The risk and benefits should be weighed prior to selecting the appropriate diagnostic modality.

Conclusion

This study was carried out to compare the accuracy of ridge mapping, Cone Beam Computed Tomography to direct intra-operative ridge measurements for measuring alveolar ridge width prior to implant placement. The following conclusions can be drawn from our study:

1. The comparison of measurements obtained from ridge mapping caliper and direct intra-operative ridge width measurements was found statistically insignificant.

2. The comparison of Cone Beam Computed Tomography measurements and direct intra-operative ridge measurements was found statistically insignificant.

3. The ridge mapping caliper as well as cone beam computed tomography could be used for accurate measurement of the alveolar ridge width.

4. The ridge mapping caliper could be used chairside for fast and accurate measurement of ridge width.

5. Cone beam computed tomography could also be used to measure the ridge width accurately. Apart from measurement of alveolar ridge dimensions it had multiple other uses and thus can be advised as per requirement of the clinician.

6. The measurement of ridge width prior to reflecting the flap not only helped in deciding the implant diameter but also gave an idea regarding the deficient ridge and whether any ridge augmentation was needed to be planned prior to placement of implant.

Similar studies on larger sample size need to be undertaken for better understanding of the role of ridge mapping and use of ridge mapping caliper or cone beam computed tomography for measuring alveolar ridge width prior to implant placement.

Declarations

Source(s) of support

NIL.

Financial and material support

NIL.

Conflicts of interest of each author/ contributor

NIL.