Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 01 Feb 2019

Relationship Between Crestal Bone Levels and Crown-to-Implant Ratio of Ultra-Short Implants With a Microrough Surface: A Prospective Study With 48 Months of Follow-Up

MD, DDS,
DDS,
PhD, MSc, DDS,
DDS,
MSc, DDS,
MD, and
MD, DMD
Page Range: 18 – 28
DOI: 10.1563/aaid-joi-D-17-00204
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The aim of this cohort study was to investigate the relationship between crestal bone levels and crown-to-implant ratio of ultra-short implants, after functional loading. Sixty patients with single or partial edentulism and alveolar bone atrophy were enrolled and treated between December 2009 and January 2016. Without using bone-grafting procedures, patients were rehabilitated with ultra-short implants characterized by a microrough surface and a 6-mm length. Clinical and anatomical crown-to-implant (C/I) ratios and crestal bone levels (CBL) were measured after a follow-up period ranging from 12 to 72 months; all peri-implant and prosthetic parameters were recorded. The data collected were statistically analyzed (P = .05). A total of 47 patients with 66 ultra-short implants were completely followed up according to described protocol. The mean follow-up was 48.5 ± 19.1 months. The mean anatomical C/I ratio was 2.2, while the mean clinical C/I ratio was 2.6 ± 0.6 at baseline and 2.8 ± 0.6 at the last follow-up appointment. Mean CBL as calculated at the baseline was 0.7 ± 0.5 mm, while at the last appointment it measured 1.0 ± 0.5 mm. The overall implant-based success rate was 96.9%, and the mean peri-implant bone loss (PBL) was 0.3 ± 0.3 mm. No statistically significant relationship was found between anatomical or clinical C/I ratio and PBL. Ultra-short implants appear to offer a predictable solution for implant-prosthetic rehabilitation in patients with edentulism and bone atrophy. A high percentage of implants were successful, with minimal crestal bone loss. The high C/I ratio did not appear to influence either peri-implant bone loss or prosthetic complication rates.

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  <sc>Figure 1</sc>
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Figure 1

(a) Element #15 has to be extracted for periodontal problems. (b) Preoperative implant site #15. (c) Radiograph after implant surgery. (d) Radiograph after abutment connection. (e) Radiograph at delivery of definitive prosthesis. (f) Radiograph at 3-year follow-up. (g) Radiograph at 4-year follow-up.


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  <sc>Figure 2. Continued</sc>
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Figure 2. Continued

(a) Preoperative radiograph. (b) Postoperative periapical radiograph. (c) Radiographic examination after abutments connection. (d) Radiographic examination after provisional prosthesis. (e) Periapical radiograph taken at delivery of the definitive fixed dental prosthesis. (f) Radiograph after 3 years of functional load.


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  <sc>Figures 3–7</sc>
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Figures 3–7

Figure 3. Implant diameter distribution. Figure 4. Box and whiskers plot of crown-to-implant (C/I) ratio (1 = anatomical, 2 = clinical at baseline, 3 = clinical at latest follow-up). Figure 5. Box and whiskers plot of crestal bone levels (CBL) at baseline (1) and at latest follow-up visit (2). Figure 6. Bivariate regression analysis with generalized estimating equations to explore the possibility of a relationship between anatomical C/I ratio and peri-implant bone loss (PBL). Figure 7. Bivariate regression analysis with generalized estimating equations to explore the possibility of a relationship between clinical C/I ratio at loading time (C/I-bl) and PBL.


Contributor Notes

Corresponding author, e-mail: giuliaricciotti5@gmail.com
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