What Is ARP?
ARP (alveolar ridge preservation) is a method adopted by dental surgeons in which the bone height and physiology that is constantly reduced by resorption following a tooth extraction is maintained in a predictable way, preventing the ridge from further resorption and maintenance of bone volume and height. The techniques of ARP mainly revolve around the usage of guided bone regeneration material (GBR), growth factors, certain socket sealers, and fillers, all of which can aid in healthy bone preservation and remodeling process in spite of the tooth being removed for whatever reasons (periodontal damage, mobility, gross decay or non vitality).
What Is the Need for ARP Techniques?
The reason why ARP should be chosen by the patients before prosthetic implantation of the missing tooth or even in severely edentulous cases for wearing dentures is that post tooth extraction, the bundle bone (the bone that lines the alveolar socket and encloses periodontal or Sharpey's fibers for tooth support in the jaw) is absorbed almost immediately whereas the alveolar bone of the jaw takes time to be resorbed. However, once it starts being resorbed, the vertical height of the tooth socket and the bony contour are slowly lost over time.
ARP technique mainly helps prevent this reduction in height and contour over time, and this is a boon clinically to improve prosthetic outcomes successfully in patients post extraction of tooth or teeth. This progressive and irreversible phenomenon can give rise to aesthetic, functional, and prosthodontic challenges as well as interfere with ideal implant placement for tooth replacement therapy. Several therapeutic attempts aimed at minimizing the post-extraction ridge atrophy have been employed, a concept defined as ' alveolar ridge preservation (ARP).
Bone remodeling is almost always negatively impacted post a tooth extraction that has been left unattended by a prosthesis like an implant, crown, or bridge for a long time span. This is mainly because the aesthetics, the contour, and the height of the alveolar ridge may often be hindered by unfavorable resorptive processes. Hence ARP follows the current trend of bone conservation and height or bony contour and shape preservation as well as the alveolar ridge to preserve the natural tissue. The need for ARP before prosthetic replacement is also because the soft tissue and periodontal ligament that is a major source and vascular strength for the socket wall of the tooth is also severed when a tooth is extracted.
What Are the Current Concepts in ARP?
Several studies have also adopted the concept of guided bone regeneration (GBR), utilizing a barrier membrane for the prevention of soft tissue ingrowth and encapsulation of the graft particles in an attempt to promote bone formation. Other methods for ARP have involved flap procedures in minimizing the surgical trauma, under the assumption that this would facilitate greater bone gain. Combinations of membrane grafting alongside bone grafting is a tested procedure in the research documentation and success rates of prosthetic replacements after ARP procedures.
Bone grafting histologically, as researched, even post six months of placement, and eventual healing within the socket (used to augment, contour, and maintain the ridge height), usually shows no major changes either in horizontal or vertical dimensions if allografts or xenografts are used. However, with the advancement in bone grafting, newer age alloplastic materials such as tricalcium phosphate crystals and bioactive polymers (glass polymers) are a few examples of showing both horizontal and vertical bone height changes making the site suitable for dental implantation.
Many factors that could have influenced the pattern of ridge resorption (single vs. multiple-rooted teeth, grafting material, a reflection of a flap, or obtaining primary wound closure) are assessed through meta-regression analyses to determine their significance. The current results of clinical research indicate significantly less horizontal and mid-buccal vertical bone loss when the reflection of flaps was avoided during the surgical procedure. This analysis is further highlighted when analyzed for obtaining primary wound closure.
What Are the Studies That Prove ARP Reduces Bone Resorption?
In this method of research analysis, the changes in the outcome measures (alveolar ridge dimensions) must have been assessed either clinically or with standardization to ensure reliability in reporting. Therefore, studies without an appropriate control group (unassisted healing without socket grafting), without resorting to outcomes (such as pure histological research on bone quality or immunohistochemistry), or with the use of two-dimensional radiographic assessment of ridge dimensions were not considered for inclusion ·
Clinical procedures (grafting material, application and type of membrane used, whether flap was raised, if primary wound closure was achieved, the allocated time or healing). Meta-analysis confirms the effectiveness of ARP in reducing the ridge loss in all the investigated outcomes in comparison with unassisted healing of extraction sockets. In these clinical observations, the potential studies must have contained at least a test and a control group, comparing post-extraction ARP via socket grafting to unassisted natural healing in non-compromised intact extraction sockets, allowing at least three months for the healing process.
Investigating ARP techniques, patients are randomized to receive porcine bone and collagen membrane, either with a full-thickness mucoperiosteal flap followed by obtaining a primary soft tissue seal or with a flapless approach aiming for a secondary soft tissue closure.
Conclusion
ARP is defined as the procedure of arresting or minimizing the alveolar ridge resorption following tooth extraction for future prosthodontic treatment including placement of dental implants. ARP procedures are being successfully adopted and used in modern-day clinical practice with the use of atraumatic extraction procedures and then bone graft substitutes to increase or maintain the bone volume and height that have proven to reduce but not eliminate the physiological cascade of post-extraction bone remodeling.
