While clinical signs and radiographic evidence sometimes point to dental implant complications, ascertaining the etiology of a patient’s perceived pain post implant placement when all parameters are within normal limits can be daunting. Dr. Scott Froum focuses on five factors that can elicit pain post implant placement that are often elusive and obscure diagnosis unless a good knowledge base is present.
Ascertaining the etiology of a patient’s perceived pain post dental implant placement when all clinical and radiographic parameters are within normal limits can be a daunting task. Clinical signs that could indicate pain from peri-implant tissue infection include bleeding upon probing, increased probing depths, suppuration, friable tissue, ulceration, etc. Radiographic evidence of problematic implants eliciting pain symptoms include radiolucent regions, mechanical failure of implant componentry, and violations of anatomy.
What should the course of action be, however, when all clinical signs are normal and the patient’s only problem is the symptom of pain? This article will focus on factors that can elicit pain post dental implant placement that are often elusive and obscure diagnosis unless a good knowledge base is present.
1. Violations of the anterior loop of the inferior alveolar canal (IAC)
As the inferior alveolar nerve (IAN) approaches the mental foramen, the canal turns upward on the buccal side of the mandible. The IAN emerges from the mental foramen and generates the mental nerve. Then mental portion of the IAC can course straight, vertical, or in an anterior loop fashion. In the anterior loop, the nerve runs upward and courses toward mid mandible before looping and heading back toward the mental foramen (figure 1). The literature (1) has reported variations in the prevalence of the anterior loop from 7%–88%, with a mean prevalence of around 28%. (2) Trauma to this region (mandibular premolar-incisor) can induce sensory disturbance, increased bleeding, and pain post implant therapy in a region otherwise known as a “safe area.”
Figure 1: Courtesy Journal of Dental Implants
2. Violations of a branch of a bifid or trifid mandibular canal
The IAC is typically described as a singular canal (3) containing the neurovascular bundle that clinicians know not to violate and a 2 mm “safety zone” (4) has been described when placing dental implants. It is now known that multiple smaller branches of the IAC can occur that run parallel to the main trunk of the canal. (5) Up to 40% of the nerve can branch off the main canal, and if these branches are large enough, a secondary or even tertiary canal can result (figure 2). Multiple branches of the mandibular canal often go unrecognized, because many dentists are unaware of this anatomic variation even though the canals may be visible on a panoramic radiograph or CT scan. Violations of this secondary/tertiary canal resulting in pain post implant placement have been described in the literature. (6)
3. Inadequate keratinized tissue around the dental implant crown
There is no consensus in the literature regarding the need for adequate keratinized tissue around a dental implant (usually described as being at least 2 mm in width). Some studies have suggested, however, that a lack of keratinized tissue can lead to pain post implant placement and/or restoration (figure 3). (7) These symptoms are most notably elicited upon palpation by brushing, eating, and percussion.
4. Poor bone-to-implant contact
Although an implant may seem to be surrounded by bone on a two-dimensional and even a three-dimensional radiograph and CT scan, that bone may be of poor quality and/or not completely intimate with the implant surface (figure 4). Poor bone-to-implant contact can occur when fibrous tissue encapsulates the body of the implant, which is then layered with bone. Radiographically the implant appears as if the bone levels are normal, and clinically the implant may exhibit no signs of mobility; however, the patient still experiences dental pain. This can be evident especially when the implant is put into function with a healing abutment or loaded with a crown.
5. Predisposing risk factors toward postoperative dental pain
There have been reports in the literature that certain risk factors can exist within the medical/genetic makeup that may predispose a patient to persistent pain post implant therapy. (8) These risk factors include fibromyalgia, temporomandibular disorders, visceral pain hypersensitivity disorders, chronic pain, depression/anxiety, etc. All of these factors can result in pain with unknown etiology. This type of pain is usually placed under the umbrella of “peripheral painful traumatic trigeminal neuropathy” (PPTTN).
In conclusion, there are a many reasons a patient can have pain post dental implant therapy, despite demonstrating the typical clinical and radiographic signs. It is easy to label this type of pain as having a psychosomatic origin, but further evaluation of all factors—including those previously described in this article—should be ruled out prior to a diagnosis such as this.
1. Jacobs R, Mraiwa N, vanSteenberghe D, Gijbels F, Quirynen M. Appearance, location, course, and morphology of the mandibular incisive canal: an assessment on spiral CT scan. Dentomaxillofac Radiol. 2002;31(5):322-327.
2. Sahman, Sisman Y. Anterior loop of the inferior alveolar canal: a cone-beam computerized tomography study of 494 cases. J Oral Implantol. 2016;42(4):333-336. doi: 10.1563/aaid-joi-D-15-00038.
3. White SC, Pharoah MJ. Oral Radiology: Principles and Interpretation. 7th ed. Philadelphia, PA: Elsevier Mosby; 2014.
4. Misch CE. Root form surgery in the completely edentulous mandible: Stage I implant insertion. In: Contemporary Implant Dentistry. 2nd ed. St Louis, MO: CV Mosby Co.; 1999:24.
5. Maqbool A, Sultan AA, Bottini GB, Hopper C. Pain caused by a dental implant impinging on an accessory inferior alveolar canal: a case report. Int J Prosthodont. 2013;26(2):125-126. doi: 10.11607/ijp.3191.
6. Aljunid S, AlSiweedi S, Nambiar P, Chai WL, Ngeow WC. The management of persistent pain from a branch of the trifid mandibular canal due to implant impingement. J Oral Implantol. 2016;42(4):349-352. doi: 10.1563/aaid-joi-D-16-00011.
7. Greenstein G, Cavallaro J. The clinical significance of keratinized gingiva around implants. Compend Contin Educ Dent. 2011;32(8):24-31; quiz 32, 34.
8. Delcanho R, Moncada E. Persistent pain after dental implant placement: a case of implant-related nerve injury. J Am Dent Assoc. 2014;145(12):1268-1271.
Scott Froum, DDS, a graduate of the State University of New York Stony Brook School of Dental Medicine, is a periodontist in private practice in New York City. He is the editorial director of Perio-Implant Advisory e-newsletter, as well as a contributing author for DentistryIQ and Dental Economics. Dr. Froum, a diplomate of the American Board of Periodontology, is a clinical associate professor at both SUNY Stony Brook and the NYU Dental School in the Department of Periodontology and Implantology. He serves on the board of editorial consultants for the Academy of Osseointegration's Academy News. Contact him by e-mail at firstname.lastname@example.org or through his website at drscottfroum.com.