Alveolar bone is precious, especially since it is easier to lose it than gain it. These days, it is becoming even more valuable in the optimal placement of a dental implant. Preserving bone reduces the need for grafting procedures and improves the aesthetics of a final prosthesis.
Yet, preserving as much bone volume and height as possible after an extraction can be challenging. Our Surgical Extraction Course at ARIA focuses on atraumatic extractions and other means to maintain as much ridge as possible.
The Resorption and Healing Process
After a tooth is extracted from its socket, resorption in this area is inevitable. Let’s begin by reviewing this process. Alveolar ridge resorption can be divided into two phases:
- The first phase involves the bundle bone being resorbed and replaced with woven bone. This reduces the bone height, especially on the buccal aspect of the socket. This may partly be due to thinner bone width in this area.
- The second phase is resorption from the outer surface of both bone walls, causing horizontal and vertical tissue contraction. The specific cause is unknown, but it may be due to disuse atrophy, decreased blood supply or localised inflammation.
The resorptive process is faster during the first 6 months after extraction, and then continues at an average of 0.5-1.0% per year. As a result, two thirds of the soft and hard tissue changes occur in the first three months (Schropp, Wenzel, Kostopoulos & Karring, 2003).
Fortunately, some bone formation does occur in the healing process. Extraction sockets are filled with delicate cancellous bone in the apical two thirds by 10 weeks, and completely filled with bone at 15 weeks. Increased radiopacity is noticeable as early as 38 days, and is of similar opaqueness to surrounding bone by 105 days (Mangos, 1941).
The overall result is generally a reduced vertical height and a more palatal ridge in relation to the original tooth position. One consequence of this is placing a dental implant too lingual.
The buccal bone around this socket is already quite thin
Image courtesy of Dr Praveen Nathaniel
How to Minimise Alveolar Ridge Resorption
Two main methods we focus on at ARIA are reducing extraction trauma and limiting flap elevation. We also provide insight into bone regeneration techniques, including different membranes and bone substitutes. This can help reduce bone resorption during the healing process, and thus augment bone volume. Hands-on practice at atraumatic extractions and bone substitutes are provided at our courses.
Socket grafting enhances the alveolar ridge morphology
L. Schropp, A. Wenzel, L. Kostopoulos, and T. Karring, “Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study,” International Journal of Periodontics and Restorative Dentistry, vol. 23, no. 4, pp. 313–323, 2003.
J. G. Mangos, “The healing of extraction wounds: a microscopic and ridographic investigation,” New Zeeland Dental Journal, vol. 37, pp. 4–23, 1941.