Journal of Dental Implants
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Table of Contents
ORIGINAL ARTICLE
Year : 2021  |  Volume : 11  |  Issue : 2  |  Page : 84-88

Radiographic assessment of alveolar bone loss around customized root analog zirconia implants placed in fresh extraction sockets


1 Department of Oral and Maxillofacial Surgery, Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra, India
2 Department of Oral Pathology and Microbiology, Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra, India

Date of Submission12-Jul-2021
Date of Decision13-Oct-2021
Date of Acceptance13-Oct-2021
Date of Web Publication14-Dec-2021

Correspondence Address:
Dr. Rakhi S Purkayastha
Department of Oral and Maxillofacial Surgery, Bharati Vidyapeeth Dental College and Hospital, Pune - 411 043, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jdi.jdi_13_21

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   Abstract 


Aim: The aim of this study is to evaluate the radiographic assessment of alveolar bone loss around customized root analog zirconia implants placed in fresh extraction sockets using the cone-beam computed tomography at predetermined intervals.
Subjects and Methods: The present study comprised twenty individuals all above 18 years with at least one tooth indicated for extraction. The twenty participants were considered in a single group who underwent single tooth extraction followed by the placement of root analog zirconia implant after 7 days which was fabricated using computer-aided design and computer-aided manufacturing technology. The participants were evaluated radiographically using Cone-Beam Computed Tomography (CBCT) at predetermined intervals: • Within 48 h of implant placement (CBCT I) • At the time of composite crown cementation on zirconia implant after 4 months of placement (CBCT II) • After 4 months of composite crown cementation (CBCT III). The alveolar bone loss was measured on all the four surfaces of the implant. CBCT was used only for the required area so to avoid total radiation exposure to the patient.
Statistical Analysis Used: The survival of dental implants was computed using the Kaplan–Meier method. The comparison of the mesial, distal, buccal, and lingual bone height at 3 different time intervals was analyzed using the repeated-measures analysis of variance.
Results: Radiographic assessment of alveolar bone loss around customized root analog zirconia implants placed in fresh extraction sockets in predetermined time interval using the cone-beam computed tomography (CBCT) was taken to be statistically significant (P ≤ 0.05).
Conclusions: An innovative technique for immediate replacement of extracted tooth using customized Zirconia root analog implant was introduced. In future, long-term evaluation with more sample size is necessary to assess the success and survival of implant placed using this technique.

Keywords: Custom-made implants, immediate implantation, root analog implants, zirconia implant


How to cite this article:
Patankar A, Kshirsagar R, Patankar S, Purkayastha RS, Pawar S, Nair K. Radiographic assessment of alveolar bone loss around customized root analog zirconia implants placed in fresh extraction sockets. J Dent Implant 2021;11:84-8

How to cite this URL:
Patankar A, Kshirsagar R, Patankar S, Purkayastha RS, Pawar S, Nair K. Radiographic assessment of alveolar bone loss around customized root analog zirconia implants placed in fresh extraction sockets. J Dent Implant [serial online] 2021 [cited 2022 Jan 20];11:84-8. Available from: https://www.jdionline.org/text.asp?2021/11/2/84/332468




   Introduction Top


Replacement of failing or ailing natural teeth with dental implants has become an alternative treatment option since the discovery of osseointegration by P.-I. Branemark in the early 1960s.[1] Dental implant offers predictable, functional, and secure means for tooth replacements.[2]

Amalgamating the technologies of cone-beam computed tomography (CBCT), computer-aided design (CAD), and computer-aided manufacturing (CAM) leads to advancement in the field of implant dentistry. One exceptional advancement is to produce a customized Zirconia root analog implant as an alternative to the traditional threaded, straight or tapered, standard dental implant systems. This implant will have similar dimensions to the original root and would be in harmony with the root socket. Probable benefits include uncomplicated immediate implant placement, decreased number of surgeries, and increased patient comfort. Furthermore, identical root features might result in a higher esthetic outcome.[3]

Zirconia is known for its superior biocompatibility, decreased plaque accumulation, and enhanced esthetic results (by diminishing dark discoloration of the gingiva and unveil titanium roots in case of gingival recession). It has high compressive strength and bending forces, fracture toughness, and high electrical resistance.[4] The root surface was improved in two ways, by adding micro-retentions to the entire root surface and limiting macro-retentive elevations to the interdental space. The implant diameter was narrowed next to the thin cortical bone to avoid fracture and pressure-induced bone loss. A single-stage implantation was used, resulting in immediate with reduced, functional loading.[5] So far, clinical data regarding the root analog implant technique remain sparse. The aim of the present study is radiographic assessment of alveolar bone loss around customized root-analog zirconia implants placed in fresh extraction sockets at predetermined intervals using cone-beam computed tomography (CBCT).


   Subjects and Methods Top


All patients were provided an information sheet and were explained in detail regarding the study, written informed consent before the procedures was attained. The study was approved by the Review Board and Ethics Committee of the institute.

The study population comprised 20 patients (11 males and 09 females), mean age 38.25 years (standard deviation [SD] =9.00), range from 24 to 40 years, requiring single tooth extraction followed by the placement of root analog zirconia implant after 7 days which was fabricated using CAD/CAM technology.

Inclusion criteria:

  1. Patients who require extraction of single-rooted tooth and willing to participate in the study were included in the study
  2. Patients willing for implant placement
  3. Patients above 18 years of age
  4. Patients with no local or systemic contraindications for dental implants.


Exclusion criteria:

  1. Patients below 18 years
  2. Local conditions not suitable for implant – before/after extraction
  3. Patients not prepared to volunteer for the study, poorly motivated patients or unable to keep the follow-up.


Twenty patients visiting the Department of Oral and Maxillofacial Surgery, requiring extraction of single-rooted tooth and willing to participate were included in this prospective study.

Detailed case history and routine required investigations were taken for all patients participating in the study. Strict sterilization protocol was followed throughout the study and sterile armamentarium used.

The twenty participants were considered in a single group who underwent single tooth extraction.

After meticulous and careful extraction, the extraction socket was cleaned using curettage and cotton gauze soaked in iodoform was placed in the socket.

The patient was prescribed Amoxicillin 500 milligram (mg) two times a day and Paracetamol 500 milligram (mg) two times a day each for 5 days, respectively.

The root of the extracted tooth was modified to incorporate macro-retentions on the proximal surfaces (mesial and distal) using light cure composite resin of 0.5 mm thickness. The root diameter was reduced by 0.1–0.3 millimeter (mm) next to the buccal and lingual/palatal face to prevent fracture of thin cortical plates at the time point of insertion of zirconia implant. In addition, a preparation simulating a crown prepared for coronal prosthesis was designed in continuity with the implant (one/single piece).

The zirconia implant was then fabricated using CAD-CAM technology.

In dental laboratory, the implant was then milled from a zirconium dioxide block, and the surface was roughened by sandblasting and sintered for 8 h to achieve the desired mechanical properties.

The customized zirconia root analog implant was cleaned in an ultrasonic bath using 96% ethanol for 10 min. Later, the implant was packed in a sterile pouch and steam sterilized in Class B type autoclave.

The patient was recalled on the 7th day after the extraction.

The cotton gauze soaked in iodoform was removed from the socket and flushed with sterile physiologic saline solution after suitable local anesthesia.

The custom-made individualized root analog implant was then placed into the socket under digit pressure and subsequent gentle tapping with a hammer and a mallet.

Primary stability was established in all patients as checked by palpation and percussion.

Radiographic evaluation was made by using CBCT at predetermined intervals:

  • Within 48 h of implant placement (CBCT I)
  • At the time of composite crown cementation on zirconia implant after 4 months of placement (CBCT II)
  • After 4 months of composite crown cementation (CBCT III).


The alveolar bone loss was measured on all four surfaces of the implant. CBCT was used only for the required area so to avoid total radiation exposure to the patient.


   Results Top


Descriptive statistics were expressed as means and SD. The survival of dental implants was computed using the Kaplan–Meier method. Comparison of the mesial, distal, buccal, and lingual bone height at three different time intervals was analyzed using the repeated measures analysis of variance. In the above tests, P value less than or equal to 0.05 (P ≤ 0.05) was taken to be statistically significant. The analysis was performed using the SPSS software version 20 (Shivam Laboratory, Pune, Maharashtra, India).

The study population comprised 20 patients (11 males and 09 females), mean age 38.25 years (SD = 9.00), range from 24 to 40 years, requiring single tooth extraction followed by placement of root analog zirconia implant after 7 days which was fabricated using CAD/CAM technology.

Primary implant stability was achieved in all patients and no complications, such as swelling, inflammation, bleeding, and pain, were observed during the follow-up period.

Implant survival is shown in [Table 1]; implants were lost within 29–210 days. Mean, i.e., average survival of the implants is 3.75 months. Moreover, upper and lower confidence intervals mean that 95% of the times if the study is repeated, the average survival time is from 2.5 months to 4.98 months. Over a period of time, there is a statistically significant reduction in the bone height on all sides [Figure 1], i.e., mesial, distal, buccal, and lingual. This can be due to the following reasons: Less surface area as compared to the threaded design of implants, patients started eating from the same side unknowingly, implant was not completely covered by gingiva to have undisturbed healing, and sterilization protocol may be inadequate which attributed to the failure of the dental implants to osseointegrate.
Table 1: Kaplan Meier survival estimate

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Figure 1: Radiographic assessment of alveolar bone loss around customized root-analog zirconia implants placed in fresh extraction sockets. Comparison of the mesial, distal, buccal, and lingual height of the bone at different time intervals

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The graph shows that as time progressed, implant survival went down (implants were lost). Implant survival as computed according to the Kaplan–Meier method is depicted in [Figure 2]. A total of five implants survived out of 20. Twenty-five percent implants survived with an unaltered extraction socket compared with the clinical situation immediately after initial tooth extraction.
Figure 2: Kalpan−Meier survival analysis

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Implants loosened and were lost suddenly without prior pain or infection. In one case, the patient met with an accident and was diagnosed with a mandibular body fracture. The implant, which was clinically functioning without a crown, was removed easily on day 203 with mild resistance, indicating loose adherence. None of the implants were restored with a crown, because of the early loss.

Owing to the inferior results, based on the lack of osseointegration, patient enrolment was stopped after only 20 patients.

After 4–5 months, a composite crown was cemented in five patients. Patients were followed for 8–24 months. At the latest follow-up, five implants were assessed as stable and successful, and no complications were detected. Each follow-up revealed a clinically healthy marginal area, and no swelling or pain was reported. Probing depths ranged from 1 to 4 mm. Clinically, the mucosa around the implants was free of inflammation. There was no wound infection, no signs of periodontitis, and no implant mobility. No implants were lost during the functional loading period, and none of the patients needed treatment in the follow-up period. [Figure 3] and [Figure 4] show the radiograph before extraction, placement of customized zirconia root analog, composite crown placement, and postoperative radiograph.
Figure 3: Radiograph before extraction

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Figure 4: (a) Placement of customized zirconia root analog. (b) Composite crown placement. (c) Postoperative radiograph

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   Discussion Top


This study describes a novel approach to dental root replacement in humans using customized Zirconia root analog and evaluates the radiographic assessment of alveolar bone loss around customized root-analog zirconia implants placed in fresh extraction sockets prospectively in patients.

With the combination of CBCT and CAD-CAM technology, it was possible to fabricate a customized zirconia root analog with accuracy. Since 15 patients complained of loose implants out of twenty patients, enrolment was stopped.

A tooth imitation implant was promulgated in early 1969, but the polymethacrylate tooth analog was enclosed by the soft tissue instead of osseointegration.[6]

Kohal et al. reported a study of custom-made, sandblasted zirconia implants with metal crowns in the maxillae of 12 monkeys. All implants were stable with no mechanical complications. On the contrary, in a human trial, all implants failed in spite of being exposed to partial load. This shows that only root mimicking design with micro-retention does not result in osseointegration in the clinical situation. An ideal root analog fit with no retention leads to good primary stability but may result in failure in intermediate term following constant pressure-induced resorption on the entire alveolar surface, resulting in a loosened interlock between the implant and in-growth bone. This forbids secondary stability of conical root analog implant.[7]

Microtopography causes osteoblastic cells to secrete factors that enhance differentiation and alters their responses to osteogenic factors, while decreasing osteoclast formation and activity.[8] In our study, a horizontal ridge was present to enhance macro-retention, and the surface of the implant was sandblasted to enhance micro-retention. However, sand blasting may be not effective due to the high rigidity of zirconium.

In the present study, 15 root analog zirconia implants were unsuccessful, and only 5 implants are still intact with follow-up of 2 years. The probable causes can be:

  • Patients started eating from the same side unknowingly
  • Less surface area as compared to the threaded design of implants
  • Implant not completely covered by gingiva to have undisturbed healing
  • Sterilization protocol may be inadequate.


The present study reports 25% success rate in root identical zirconia replicas with a surface roughened only by sandblasting which is unsatisfactory. Further studies on a larger group of population are recommended for greater authenticity and positive result.

Acknowledgment

The authors would like to thank Dr. Khushboo Thakkar (statistician).

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Tagliareni JM, Clarkson E. Basic concepts and techniques of dental implants. Dent Clin North Am 2015;59:255-64.  Back to cited text no. 1
    
2.
Tolstunov L. Surgical algorithm for alveolar bone augmentation in implant dentistry. Oral Maxillofac Surg Clin North Am 2019;31:155-61.  Back to cited text no. 2
    
3.
Moin DA, Hassan B, Wismeijer D. Immediate nonsubmerged custom root analog implants: A prospective pilot clinical study. Int J Oral Maxillofac Implants 2018;33:e37-44.  Back to cited text no. 3
    
4.
Kohal RJ, Att W, Bächle M, Butz F. Ceramic abutments and ceramic oral implants. An update. Periodontol 2000 2008;47:224-43.  Back to cited text no. 4
    
5.
Pirker W, Kocher A. Immediate, non-submerged, root-analogue zirconia implant in single tooth replacement. Int J Oral Maxillofac Surg 2008;37:293-5.  Back to cited text no. 5
    
6.
Kohal RJ, Weng D, Bächle M, Strub JR. Loaded custom-made zirconia and titanium implants show similar osseointegration: An animal experiment. J Dent 2004;32:153-9.  Back to cited text no. 6
    
7.
Pirker W, Kocher A. Immediate, non-submerged, root-analogue zirconia implants placed into single-rooted extraction sockets: 2-year follow-up of a clinical study. Int J Oral Maxillofac Surg 2009;38:1127-32.  Back to cited text no. 7
    
8.
Puleo DA, Thomas MV. Implant surfaces. Dent Clin North Am 2006;50:323-38, v.  Back to cited text no. 8
    


    Figures

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

  [Table 1]



 

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