CLINICAL FEATURE
The concept of a tooth bank in dental clinics: Turning waste into a future resource
By Dr How Zhuo Yuan
Imagine that the teeth extracted during routine dental procedures could be preserved rather than discarded as clinical waste. What if those extracted teeth could be stored and later used as a highly compatible bone graft material for dental implants? In 2003, when the concept of auto- tooth bone grafting first emerged in dentistry, it highlighted the potential for extracted teeth to be repurposed as future bone graft material. This innovative idea is at the heart of the “tooth bank” concept, where a dental clinic offers patients the opportunity to save their extracted teeth for future use as auto-tooth bone grafts. Many articles have focused on preserving mesenchymal cells in baby teeth, vital permanent premolars and wisdom teeth under the tooth bank concept, focusing on dental stem cell banking service. However, little has been discussed on the hard tissue from extracted poor prognosis, non-vital or root-treated teeth, which typically ends up in the yellow bin as waste. Auto-tooth bone graft The chemical composition of dentin closely resembles that of bone. Alveolar bone consists of 61% inorganic material, 32% organic material, and water, whereas dentin contains 65% inorganic substances and 29% organic substances and water. Cementum, on the other hand, is made up of 45-50% inorganic material and 50- 55% organic material and water. 1
According to inorganic component analysis, autogenous tooth bone graft material is composed of five biological calcium phosphates, including low- crystalline hydroxyapatite and other calcium phosphate minerals such as tricalcium phosphate (TCP), amorphous calcium phosphate, dicalcium phosphate dihydrate, and octacalcium phosphate. These calcium phosphates interact with each other and are effective in remodeling existing bone when used as graft material. Consequently, the lower the crystallinity of the carbonic apatite found in bone and tooth, the more osteoconductive the material becomes when applied as a bone graft. 2,3 The organic components of demineralised dentin matrix (DDM) include type I collagen and various growth factors like bone morphogenetic proteins (BMPs), which promote bone and cartilage formation. Additionally, non-collagenous proteins such as osteocalcin and osteonectin, which are associated with calcification, are present. Dentin-specific proteins, including phosphoprotein (phosphophoryn) and dentin sialoprotein, have also been identified in the dentin matrix. 4 It is also well known that appropriate demineralisation process does not denature the type I collagens, growth factors, and non-collagenous proteins so that the DDM can maintain osteoinductive-healing capacities. 4-8
The applications of auto-tooth bone graft include:
1. Bone and sinus augmentation for implant surgeries.
2. Guided bone regeneration in case of periodontal defects or prior to implant placements. 3. Alveolar bone grafting in cases of cleft palate patients 9 and post wisdom tooth surgery to prevent periodontal abnormalities distal to second molar. 10 4. Ridge augmentation before placing implants. Various clinicians have reported using block-type of auto- tooth bone graft where defect is more than 3mm. 11 5. Socket preservation and reconstruction to minimise bone loss from secondary healing of extraction socket and increase quality and quantity of healed socket, either grafting with or without membrane. 12 HOW IT WORKS: THE PROCESS OF STORING AND UTILISING EXTRACTED TEETH A tooth bank is a service that can be offered within a dental clinic for the patients, an opportunity to store their extracted teeth under controlled conditions, typically 75% ethanol. When a tooth is extracted, it is immediately collected by the dental clinic for preservation. The clinic
32 DENTAL ASIA SEPTEMBER / OCTOBER 2024
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