Custom-made 3D printed subperiosteal titanium implants for the prosthetic restoration of the atrophic posterior mandible of elderly patients: a case series

Custom-made 3D printed subperiosteal titanium implants for the prosthetic restoration of the atrophic posterior mandible of elderly patients: a case series

1. Scientific Reference

• Study Title: Custom-made 3D printed subperiosteal titanium implants for the prosthetic restoration of the atrophic posterior mandible of elderly patients: a case series
• Authors: Carlo Mangano, Andrea Bianchi, Francesco Guido Mangano, Jessica Dana, Marco Colombo, Ivan Solop, Oleg Admakin
• Scientific Journal: 3D Printing in Medicine
• Year of Publication: 2020
• DOI: 10.1186/s41205-019-0055-x

2. Scientific Background

Implant treatment of severely atrophic posterior mandibular regions remains a major clinical challenge, particularly in elderly patients. When the residual bone volume becomes insufficient to accommodate conventional endosseous implants, bone regeneration protocols are often considered the preferred therapeutic option. However, these procedures increase surgical complexity, treatment duration, and potential morbidity.

The recent evolution of the digital workflow in implantology, combining CBCT, computer-aided design (CAD), and metallic additive manufacturing, opens the way to new personalized approaches. In this context, subperiosteal implants, historically abandoned due to technical difficulties and frequent complications, are now benefiting from advances in 3D printing and direct metal laser sintering (DMLS) technology. This study is part of this trend by evaluating the use of customized subperiosteal implants in elderly patients presenting with severe posterior mandibular atrophy.

3. Study Objective

The primary objective of this case series was to evaluate the clinical use of custom-made titanium subperiosteal implants manufactured by 3D printing for the fixed prosthetic rehabilitation of the atrophic posterior mandibular region in elderly patients.

The authors specifically investigated implant adaptation to the bone site, surgical duration, implant survival, and the occurrence of potential postoperative and prosthetic complications.

4. Methodology

This publication corresponds to a clinical case series.

Between January 2017 and June 2018, the authors included patients over 65 years of age presenting partial edentulism in the posterior mandibular region associated with significant bone atrophy preventing the placement of conventional standard-length implants.

The selected patients did not wish to undergo bone regeneration procedures.

Planning was based on the acquisition of CBCT data and intraoral scans. The implants were digitally designed and then manufactured from titanium alloy using DMLS technology. After surgery, patients received a provisional restoration followed by a definitive zirconia-ceramic rehabilitation.

The reported clinical follow-up was 12 months. Evaluation criteria included implant adaptation, stability, operative time, implant survival, and early or late complications.

5. Main Results

Among fifteen patients initially assessed, ten were ultimately included in the study. The sample comprised four men and six women with a mean age of 69.6 years.

The adaptation of the customized implants was considered globally satisfactory by the operators, with an average score of 7 out of 10. Two implants showed insufficient adaptation, attributed to radiological artifacts that interfered with the digital reconstruction process. Nevertheless, these devices could be adjusted during surgery.

The mean duration of the surgical procedures was 44.3 minutes.

After one year of follow-up, no implant had been lost, corresponding to an implant survival rate of 100%. One early postoperative complication was observed in one patient, involving pain, discomfort, and swelling. Two late complications were also reported in the form of fractures of provisional restorations during the temporization phase. No additional prosthetic complications were described after placement of the definitive restorations.

The overall complication rate observed during follow-up reached 30%, although the authors specified that these complications were of low severity.

6. Clinical Analysis

This study illustrates the potential interest of customized subperiosteal implants in a particularly complex indication: severe atrophy of the posterior mandibular region in elderly patients refusing bone reconstruction techniques.

The most notable aspect lies in the combination of a complete digital workflow and metallic additive manufacturing. The integration of CBCT data, digital impressions, and CAD design makes it possible to produce an implant specifically adapted to the patient’s anatomy. This customization aims to improve mechanical stability and simplify the surgical phase.

The observed results suggest that this approach could represent an alternative when conventional implant solutions are limited by the proximity of the inferior alveolar nerve or by advanced bone resorption. The absence of implant loss during the first year constitutes an encouraging clinical signal.

Nevertheless, these data must be interpreted with caution. The study population is limited, and the absence of a control group does not allow direct comparison of this approach with other therapeutic strategies such as bone grafting, short implants, or alternative implant protocols. Furthermore, the twelve-month follow-up remains insufficient to assess the long-term biological stability of subperiosteal implants in elderly patients who may experience ongoing bone atrophy.

7. Clinical Applications

The results of this study may be particularly relevant in the following situations:

• Severe posterior mandibular atrophy.
• Elderly patients refusing bone grafting or guided bone regeneration procedures.
• Fixed implant rehabilitation in an unfavorable anatomical context.
• Use of a complete digital workflow combining CBCT, CAD/CAM design, and metallic 3D printing.
• Cases requiring a highly personalized implant solution adapted to the patient’s residual anatomy.

However, the available data do not allow these conclusions to be extended to other clinical indications without additional studies.

8. Level of Evidence, Limitations and Transparency

This publication corresponds to a case series, which represents a relatively low level of evidence compared with controlled trials or comparative studies.

The main limitations identified by the authors are:

• small sample size (10 patients);
• absence of a control group;
• follow-up limited to one year;
• inability to evaluate medium- and long-term performance;
• potential risk related to CBCT artifacts that may affect design accuracy.

Regarding transparency, the authors declare that they did not receive external funding for this research. However, they acknowledge the company BTK (Dueville, Italy) for manufacturing the DMLS implants. The authors declare no conflicts of interest.

9. Key Points of the Study

• Study Type: Case series
• Level of Evidence: Low to moderate (descriptive observational study)
• Population Analyzed: Elderly partially edentulous patients with posterior mandibular atrophy
• Number of Patients: 10
• Number of Implants: 10 customized subperiosteal implants
• Follow-up Duration: 1 year
• Primary Outcome Evaluated: Adaptation, stability, implant survival, and complications
• Main Result: 100% implant survival at one year
• Scientific Conclusion: Customized subperiosteal implants manufactured by DMLS appear feasible and functional in this specific indication
• Potential Limitations: Small sample size, absence of a control group, short follow-up

10. Scientific Impact

This study contributes to the contemporary re-evaluation of a historical concept in implantology: the subperiosteal implant. Its major contribution lies in the integration of modern digital technologies that make it possible to overcome some of the technical limitations that historically hindered the use of these devices.

The presented data suggest that metallic additive manufacturing may provide sufficient precision to design implants adapted to severely resorbed anatomies. The study therefore contributes to the emergence of personalized solutions for patients presenting severe bone deficiencies and for whom reconstructive protocols are refused or difficult to perform.

Although the conclusions remain preliminary, this publication provides additional clinical data supporting the use of customized subperiosteal implants and justifies the implementation of larger prospective studies with extended follow-up periods.

11. Editorial Conclusion

This case series highlights the potential of 3D-printed titanium subperiosteal implants in the implant rehabilitation of severely atrophic posterior mandibular regions in elderly patients. The one-year results are favorable, with complete implant survival and a limited number of minor complications. However, due to the small sample size and limited follow-up, these observations should be considered preliminary. Comparative studies and long-term evaluations remain necessary before precisely defining the place of this approach within the therapeutic armamentarium of modern implantology.