J Korean Assoc Oral Maxillofac Surg.  2019 Oct;45(5):260-266. 10.5125/jkaoms.2019.45.5.260.

7-mm-long dental implants: retrospective clinical outcomes in medically compromised patients

• Nguyen TT
• Eo MY
• Cho YJ
• Myoung H
• Kim SM

• KMID: 2461478
• DOI: http://doi.org/10.5125/jkaoms.2019.45.5.260

Abstract

OBJECTIVES
Dental implants shorter than 8 mm, called short dental implants (SDIs), have been considered to have a lower success rate than standard length implants. But recent studies have shown that SDIs have a comparable success rate, and implant diameter was more important for implant survival than implant length. Also, SDIs have many advantages, such as no need for sinus lifting or vertical bone grafting, which may limit use in medically compromised patients.
MATERIALS AND METHODS
In this study, 33 patients with 47 implants 7-mm long were examined over the last four years. All patients had special medical history and were categorized into 3 groups: systemic disorders, such as diabetes mellitus (controlled or uncontrolled), mental disability, and uncontrolled hypertension; oral cancer ablation with reconstruction, with or without radiotherapy; diverse osteomyelitis, such as osteoradionecrosis and bisphosphonate-related osteonecrosis of the jaw. Most of these patients have insufficient residual bone quality due to mandible atrophy or sinus pneumatization.
RESULTS
The implant diameters were 4.0 (n=38), 4.5 (n=8), and 5.0 mm (n=1). Among the 47 implants placed, 2 implants failed before the last follow-up. The survival rate of 7-mm SDIs was 95.74% from stage I surgery to the last follow-up. Survival rates did not differ according to implant diameter. The mean marginal bone loss (MBL) at 3 months, 1 and 2 years was significantly higher than at implant installation, and the MBL at 1 year was also significantly higher than at 3 months. MBL at 1 and 2 years did not differ significantly.
CONCLUSION
Within the limitations of the present study, the results indicate that SDIs provide a reliable treatment, especially for medically compromised patients, to avoid sinus lifting or vertical bone grafting. Further, long-term follow-up is needed.

Keyword

Dental implants; Survival rates; Alveolar bone loss

MeSH Terms

Alveolar Bone Loss
Atrophy
Bisphosphonate-Associated Osteonecrosis of the Jaw
Bone Transplantation
Dental Implants*
Diabetes Mellitus
Follow-Up Studies
Humans
Hypertension
Lifting
Mandible
Mouth Neoplasms
Osteomyelitis
Osteoradionecrosis
Radiotherapy
Retrospective Studies*
Survival Rate
Dental Implants

Figure

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  Fig. 1 Schematic drawing of short dental implant use in patients with insufficient residual bone volume due to sinus pneumatization (A) or mandible atrophy (B).

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  Fig. 2 Marginal bone loss (MBL) evaluation used in this study, reference lines were drawn to calculate bone loss on the mesial and distal sides of implant: longitudinal implant axis (“1”), horizontal line at the most coronal level of the implant collar (“2”), horizontal lines at the most coronal level of bone-to-implant contact at the mesial and distal sites (“3” and “4”). MBL measurement in a Stella implant (Shinhung; A) and Luna implant (Shinhung; B).

• 

  Fig. 3 Panoramic radiograms of a 76-year-old female who had squamous cell cancer, treated with maxillary mass resection and radiotherapy on the left, radical neck dissection and radiotherapy due to neck metastasis on the right (A). A 4.5 mm×7 mm Stella (Shinhung) was installed in the 47 tooth position (arrow; B). The implant achieved good stability and bone integration, and showed acceptable bone loss at 3 years (arrows; C, D).

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  Fig. 4 Panoramic radiogram of a 72-year-old male with osteomyelitis and a history of hypertension and diabetes. A. Preoperation radiogram. B. A 4 mm×7 mm Stella (Shinhung) implant was installed in the 37 tooth position (arrow). C, D. The implant achieved good stability and bone integration, and showed acceptable bone loss at 1 year (arrows).

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  Fig. 5 Panoramic radiogram of a 67-year-old female who had hypertension and osteomyelitis in the posterior right mandible. A. A previous implant installed in the 37 tooth position failed due to bone resorption. B. A 4 mm×7 mm Luna (Shinhung) implant was placed at the 16 tooth position (arrow), and a 4.5 mm×7 mm Stella (Shinhung) implant was placed at the 47 tooth position (arrow) after removal of the failed implant. C, D. The two implants showed good stability and acceptable bone loss on follow-up examination (arrows).

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