Eggshell sourced hydroxyapatite as a bone regenerative material in dentistry - a narrative review

Bone has the ability to regenerate, but in some cases, additional grafting is needed to restore shape and function when defects occur. Researchers have explored various grafting materials to support bone healing. Eggshell-derived hydroxyapatite (EHA) is one such material that has gained attention due to its unique properties. It is available in abundance and is cost-effective compared to other options. The material is also biocompatible and environmentally friendly. However, the clinical effectiveness of EHA in bone regeneration remains underexplored. Prior research has shown that hydroxyapatite supports bone growth, but eggshell-derived variants have not been widely tested. This gap motivated a review of recent studies to assess the potential of EHA and its nano-form (EnHA) in dental applications. The review aimed to evaluate the current evidence and identify areas for further investigation.

The purpose of this review was to examine the clinical potential of eggshell-derived hydroxyapatite (EHA) and its nano-form (EnHA) in bone regeneration. The study focused on human trials published between 2014 and 2024 to assess the effectiveness of these materials. The researchers aimed to determine whether EHA and EnHA could serve as viable alternatives to traditional grafting materials. They evaluated outcomes such as bone density, healing time, and new bone formation. The review also sought to compare the performance of EHA/EnHA with established grafts like demineralized freeze-dried bone allograft and synthetic hydroxyapatite. The motivation for this study was the growing need for affordable and sustainable grafting options in dentistry. Eggshells are a waste product with high calcium content, making them a promising source for bone graft materials. The study aimed to consolidate findings from recent trials to guide future research and clinical use.

The researchers conducted a narrative review of human studies published between 2014 and 2024. They searched for trials that evaluated the use of eggshell-derived hydroxyapatite (EHA) and its nano-form (EnHA) in bone regeneration. A total of seven trials involving 112 patients and 88 intervention sites were included. The studies focused on various dental applications, such as socket preservation, intrabony defects, apicoectomy, and cystic lesions. The researchers analyzed the outcomes of EHA/EnHA use in terms of bone density, healing time, and new bone formation. They compared the results with those from ungrafted areas and conventional grafts like demineralized freeze-dried bone allograft. Radiographic and histomorphometric assessments were used to evaluate bone regeneration. The review did not include animal studies or in vitro experiments to focus on clinical relevance and human applicability.

The review found that eggshell-derived hydroxyapatite (EHA) and its nano-form (EnHA) showed promising results in bone regeneration. EHA improved bone density, volume, and healing time in various dental applications. When combined with platelet-rich fibrin, EnHA consistently outperformed ungrafted areas. The outcomes were comparable to those of conventional grafts like demineralized freeze-dried bone allograft and synthetic hydroxyapatite. Radiographic and histomorphometric analyses confirmed significant improvements in bone density and new trabecular bone formation. The high calcium content and non-cytotoxic profile of EHA/EnHA supported their therapeutic potential. Efficient high-temperature sterilization methods were also noted as an advantage. However, inconsistent resorption rates and a lack of long-term data were identified as limitations. These findings suggest that EHA and EnHA are viable alternatives for bone grafting in dentistry.

The findings of this review suggest that eggshell-derived hydroxyapatite (EHA) and its nano-form (EnHA) are promising alternatives for bone grafting in dentistry. The materials demonstrated comparable outcomes to conventional grafts in terms of bone density and healing time. Their biocompatibility, affordability, and environmental benefits make them attractive options. However, the inconsistent resorption rates and limited long-term data highlight the need for further research. The authors recommend large multi-centre studies to validate long-term results. They also suggest optimizing the manufacturing process for EHA/EnHA to ensure consistency. The current evidence supports the use of these materials in clinical settings. The review emphasizes the importance of continued investigation to address existing limitations. Future studies should focus on standardizing preparation methods and assessing long-term safety and efficacy.