Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants in Oral and Maxillofacial Surgery for Severe Bone-Deficient Patients—A Pilot Study

Alexandru Nemtoi, Vlad Covrig, Ana Nemtoi, George Stoica, Ruxandra Vatavu, Danisia Haba, Irina Zetu

Full text links: https://pubmed.ncbi.nlm.nih.gov/36292220/

Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants in Oral and Maxillofacial Surgery for Severe Bone-Deficient Patients—A Pilot Study

1. Scientific Reference

• Study Title: Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants in Oral and Maxillofacial Surgery for Severe Bone-Deficient Patients—A Pilot Study
• Authors: Alexandru Nemtoi, Vlad Covrig, Ana Nemtoi, George Stoica, Ruxandra Vatavu, Danisia Haba, Irina Zetu
• Scientific Journal: Diagnostics
• Year of Publication: 2022
• DOI: 10.3390/diagnostics12102531

2. Scientific Background

The management of patients presenting with severe maxillary or mandibular bone atrophy remains one of the major challenges in modern implantology. When the residual bone volume is insufficient to allow the placement of conventional endosseous implants, bone reconstruction procedures may be considered. However, these interventions often increase therapeutic complexity, treatment duration, and the risk of postoperative complications.

In this context, subperiosteal implants are attracting renewed interest thanks to advances in the digital workflow in oral surgery. The combination of three-dimensional imaging, computer-assisted planning, and additive manufacturing technologies now makes it possible to design customized structures adapted to the patient’s anatomy.

This technological evolution opens new perspectives for implant rehabilitation in edentulous patients or those presenting with advanced bone resorption, particularly when conventional techniques are difficult to implement.

3. Study Objective

The primary objective of this study was to present a digital protocol for the design and manufacturing of custom-made titanium subperiosteal implants produced by Direct Metal Laser Sintering (DMLS), as well as to evaluate the early and late complications observed after their placement in patients presenting significant bone resorption and unfavorable bone quality.

4. Methodology

This research corresponds to a retrospective pilot study conducted in two private oral and maxillofacial surgery centers in Romania.

Among 19 patients initially identified, 16 were ultimately included after exclusion of incomplete records. The study population consisted of 9 men and 7 women aged between 55 and 69 years.

Each patient underwent a panoramic examination and a CBCT scan associated with digital planning. The subperiosteal implants were custom-designed from three-dimensional data and subsequently manufactured in titanium using DMLS technology.

The evaluated criteria included:

• implant adaptation and stability;
• duration of the surgical procedure;
• implant survival;
• early complications;
• late complications.

The clinical follow-up reported in the study was six months for the evaluation of late complications.

5. Main Results

A total of 16 customized subperiosteal implants were placed in the included patients. Eleven implants were inserted in the maxilla and five in the mandible.

The adaptation of the implants to the osseous structures was considered globally satisfactory, with an average score of 4 out of 5 assigned by the surgeons. Twelve implants received an evaluation considered good to excellent, while only one implant exhibited insufficient adaptation.

The mean duration of surgical procedures was 86.18 minutes. Procedures performed in the maxilla required more time than those performed in the mandible.

Only one implant was lost during follow-up. According to the authors, this failure was associated with insufficient adaptation of the structure and recurrent infections that did not respond to treatment.

Regarding postoperative complications, pain, edema, and swelling were mainly limited to the first days following surgery. Major late complications such as implant mobility, suppuration, or persistent pain were not reported. Partial implant exposure was nevertheless observed in six patients without any reported functional impairment. One fracture of a provisional prosthesis was also described.

6. Clinical Analysis

This study illustrates the potential of custom-made subperiosteal implants manufactured using DMLS technology in situations where conventional implant options may be limited by advanced bone atrophy.

The principal interest lies in the use of a complete digital workflow integrating CBCT imaging, computer-aided design, and additive manufacturing. This approach aims to improve the anatomical adaptation of implant structures, a factor that appears to be decisive in the observed outcomes. The only reported failure concerned precisely an implant presenting insufficient fit.

From a clinical perspective, the results suggest that this strategy could represent an alternative for certain edentulous or severely resorbed patients who refuse or are not candidates for complex bone grafting procedures. The rapid achievement of fixed prosthetic support also constitutes an interesting aspect of the described protocol.

However, these results must be interpreted with caution. The study population remains limited, and the clinical follow-up is relatively short. Furthermore, the absence of a control group does not allow direct comparison of this approach with other therapeutic solutions such as bone reconstruction procedures or alternative implant protocols. Consequently, the presented data primarily allow assessment of the clinical feasibility of the technique rather than establishing its therapeutic superiority.

7. Clinical Applications

The results of this study may be particularly relevant in several clinical situations:

• patients presenting severe maxillary or mandibular bone atrophy;
• complete or extensive edentulism with insufficient bone volume for conventional implants;
• patients refusing bone regeneration or grafting procedures;
• complex implant rehabilitation requiring advanced digital planning;
• protocols integrating CAD/CAM technologies and additive manufacturing in oral and maxillofacial surgery.

The study suggests that this approach could constitute an additional therapeutic option in selected cases, provided that appropriate surgical expertise is available.

8. Level of Evidence, Limitations and Transparency

This publication corresponds to a retrospective observational pilot study involving a limited series of patients.

The level of evidence should therefore be considered moderate to low when compared with controlled trials or large-scale prospective studies.

Among the main identifiable limitations are:

• the small sample size of 16 patients;
• the absence of a control group;
• the retrospective nature of the analysis;
• a follow-up period limited to six months for the assessment of late complications.

The authors state that they received no external funding for this research and declare no conflicts of interest.

These elements require a cautious interpretation of the results and highlight the need for additional long-term studies.

9. Key Points of the Study

• Study Type: Retrospective pilot study
• Level of Evidence: Observational case series
• Analyzed Population: Edentulous or partially edentulous patients presenting significant bone resorption
• Number of Patients: 16
• Number of Implants: 16
• Follow-up Duration: 6 months
• Primary Outcome Evaluated: Implant adaptation, implant survival, and complications
• Main Result: Loss of only one implant associated with poor adaptation and recurrent infections
• Scientific Conclusion: Custom-made DMLS titanium subperiosteal implants demonstrated satisfactory clinical outcomes in this limited cohort
• Potential Limitations: Small sample size, absence of a control group, and limited follow-up

10. Scientific Impact

This study contributes to the scientific revival of subperiosteal implants through contemporary digital technologies. Historically, these devices were progressively abandoned because of manufacturing difficulties and complications associated with earlier protocols.

The presented data suggest that the combination of CBCT imaging, computer-aided design, and direct metal laser sintering may allow this concept to be revisited using more advanced technological resources. The study therefore provides additional clinical data regarding the feasibility of this approach in the treatment of severe bone atrophy.

Although the results remain preliminary, they are consistent with the growing trend toward personalization of implant treatments. This publication also contributes to documenting the complications observed during the first months following implant placement and highlights the importance of the precision of fit of customized implant structures.

11. Editorial Conclusion

This pilot study provides interesting clinical data regarding the use of custom-made titanium subperiosteal implants manufactured using DMLS technology in patients presenting significant bone resorption. The observed results suggest good clinical feasibility and a favorable short-term survival rate. Nevertheless, the small sample size and limited follow-up require cautious interpretation. Larger prospective studies will be necessary to better define the role of this approach in the implant rehabilitation of severely atrophied maxillae and mandibles.