Post-extraction remodeling of the adult mandible

Radiographic evaluation of alveolar ridge heights of dentate and edentulous patients

OBJECTIVE

To evaluate the reduction of residual alveolar ridge height on panoramic radiographs and the differences between denture wearers and non-denture wearers.

MATERIALS AND METHODS

The study consisted of 147 individuals (74 men and 73 women) [50 were denture wearers and 50 non-denture wearers (examination groups) and 47 of them were dentate (control group)]. Individuals having diseases impacting on bone were excluded. Vertical measurements were made at 15 sites (central incisors, first premolars and molars at the left and right of both jaws and the distance between the zygoma/orbit). MANOVA (multi-variate analysis of variation) was used for the statistical analysis of the results.

RESULTS

There were significant differences between the alveolar ridge heights of dentate and edentulous groups (p < 0.001). Between the denture wearer and the non-denture wearer groups, there was significant difference in the lower jaw (p < 0.001), but no significant difference in the upper jaw (p = 0.635). There were also differences between men and women (p < 0.005) and upper and lower jaws at every measurement sites (p < 0.01).

CONCLUSION

 Reduction in residual alveolar ridge height was in close relation with gender, denture usage and edentulousness.

Edentulism and comorbid factors

INTRODUCTION

Complete edentulism is the terminal outcome of a multifactorial process involving biological factors and patient-related factors. It continues to represent a tremendous global health care burden, and will for the foreseeable future. The purpose of this review is to determine what comorbid factors exist for the completely edentulous patient.

METHODS

This literature review evaluated articles obtained via the National Library of Medicine's PubMed Website, using keywords of edentulism with various combinations of the terms comorbidity, incidence, health, nutrition, cancer, cardiovascular health, diabetes, osteoporosis, smoking, asthma, dementia, and rheumatoid arthritis. Abstracts were selected and screened, and selected full-text articles were reviewed. Articles were limited to those with adequate patient cohorts and a minimum of 2-year follow-up data.

RESULTS

Edentulism was found to be a global issue, with estimates for an increasing demand for complete denture prostheses in the future. Completely edentulous patients were found to be at higher risk for poor nutrition, coronary artery plaque formation (odds ratio 2.32), to be smokers (odds ratio 2.42), to be asthmatic and edentulous in the maxillary arch (odds ratio 10.52), to being diabetic (odds ratio 1.82), to having rheumatoid arthritis (odds ratio 2.27), and to having certain cancers (odds ratios varying from 1.54 to 2.85, depending on the type of cancer). Chronic residual ridge resorption continues to be the primary intraoral complication of edentulation, and there appear to be few opportunities to reduce bone loss in the edentulous patient.

CONCLUSIONS

While the completely edentulous patient seems to be at risk for multiple systemic disorders, whether development of these disorders is causal or casual has not been determined. To minimize the loss of residual alveolar ridges, exemplary complete denture therapy, along with the establishment of routine recall systems, should be the ultimate goal of treatment of this patient cohort.

The pathogenesis of bisphosphonate-related osteonecrosis of the jaw: so many hypotheses, so few data

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) has generated great interest in the medical and research communities yet remains an enigma, given its unknown pathogenesis. The goal of this review is to summarize the various proposed hypotheses underlying BRONJ. Although a role of the oral mucosa has been proposed, the bone is likely the primary tissue of interest for BRONJ. The most popular BRONJ hypothesis-manifestation of necrotic bone resulting from bisphosphonate--induced remodeling suppression--is supported mostly by indirect evidence, although recent data have shown that bisphosphonates significantly reduce remodeling in the jaw. Remodeling suppression would be expected, and has been shown, to allow accumulation of nonviable osteocytes, whereas a more direct cytotoxic effect of bisphosphonates on osteocytes has also been proposed. Bisphosphonates have antiangiogenic effects, leading to speculation that this could contribute to the BRONJ pathogenesis. Compromised angiogenesis would most likely be involved in post-intervention healing, although other aspects of the vasculature (eg, blood flow) could contribute to BRONJ. Despite infection being present in many BRONJ patients, there is no clear evidence as to whether infection is a primary or secondary event in the pathophysiology. In addition to these main factors proposed in the pathogenesis, numerous cofactors associated with BRONJ (eg, diabetes, smoking, dental extraction, concurrent medications) could interact with bisphosphonates and affect remodeling, angiogenesis/blood flow, and/or infection. Because our lack of knowledge concerning BRONJ pathogenesis results from a lack of data, it is only through the initiation of hypothesis-driven studies that significant progress will be made to understand this serious and debilitating condition.

Ovariectomy reduces the gelatinolytic activity and expression of matrix metalloproteinases and collagen in rat molar extraction wounds

Osteoporosis is commonly associated with estrogen deficiency. However, the mechanisms by which the lack of this hormone causes bone loss are poorly understood. The bone structure of the oral cavity seems to be affected by estrogen deficiency, since a delayed healing process after tooth extraction has been observed after ovariectomy in rats. The aim of this study was to describe the effect of the absence of estrogen on the expression and activity of matrix metalloproteinases (MMC)-2 and -9 and expression of types I and III collagens in the alveolar granulation tissue of young female rats after tooth extraction. Sixty-six, four-week-old female rats underwent bilateral ovariectomies (OVX) or sham operations. Three weeks later, both first and second mandibular molars were extracted and the animals were killed by cervical dislocation 3, 5, or 7 days after tooth extraction. The granulation tissues were collected from the extracted alveolar sockets and used for zymographic, Western blot, or reverse transcription polymerase chain reaction (RT-PCR) analysis. There was a gradual increase on the expression of all studied proteins as well as MMP-2 and -9 activities in the periods after surgery. In contrast, OVX animals showed a significant decrease in the gelatinolytic activities and expression of MMP-2 and -9 and types I and III collagens. The results presented here in suggest that the absence of estrogen may possibly contribute to the delayed alveolar wound healing by interfering with the extracellular matrix turnover.

Ultrasound measurement of mandibular arterial blood supply: Techniques for defining ischemia in the pathogenesis of alveolar ridge atrophy and tooth loss in the elderly?

PURPOSE

To adapt ultrasound methods used to measure blood flow in the extremities to quantify mandible blood flow in order to determine the role of ischemia in the pathogenesis of mandible atrophy and tooth loss in the elderly.

PATIENTS AND METHODS

Doppler and duplex ultrasound techniques as used in measurement of arterial pulse in the extremities were adapted for recording the intraoral pulse profile at 7 sites in 57 patients of varying ages.

RESULTS

After omitting the large number (26 patients) with signals of indeterminate strength, the mental artery pulse was strong in 11 of 12 (92%) in those younger than 65 versus 9 of 19 (47% in those older than 65 years; P = .02). The equivalent figures for the sublingual artery were 15 of 15 strong for those younger than 65 and 11 of 17 (65%) for those older than 65 years ( P = .02). The varying depth of soft tissue overlying the inferior alveolar artery made its signal difficult to evaluate, but there was no statistically significant age-related difference in the inferior alveolar artery signals. In 4 elderly patients (2 with established carotid artery disease), Doppler and duplex scanning showed reversal of mental artery flow, indicating collateral flow to the mandible.

CONCLUSIONS

Ultrasound Doppler techniques used for measuring peripheral arterial flow can be adapted to quantify mandible alveolar ridge perfusion. This provides means to evaluate the role of arterial obstruction in mandible alveolar ridge atrophy and tooth loss in the elderly. The mental artery is the best site for this purpose. Preliminary data suggest an age-related reduction in mental artery flow.

Hemorrhaging Associated With Endosseous Implant Placement in the Anterior Mandible: A Review of the Literature

The placement of endosseous dental implants is largely considered a safe surgical procedure. However, upper airway obstruction secondary to severe bleeding in the floor of the mouth has been occasionally reported as a rare but potentially fatal complication of implant surgery. This review presents critical hemorrhagic episodes, related to dental implantation in the anterior segments of the mandible, published to date. Massive internal bleeding in the highly vascularized region of the floor of the mouth is the result of an arterial trauma induced by instrumentation, usually through a perforation of the lingual cortical plate. Depending on the clinical situation, hemorrhage may commence immediately or with some delay after the vascular insult. The progressively expanding lingual, sublingual, submandibular, and submental hematomas have the tendency of displacing the tongue and floor of the mouth to obstruct the airway. Because the course of airway deterioration to complete occlusion may be rapid, ensuring a patent airway is of highest priority. Even though upper airway obstruction is potentially life-threatening, a secure airway was successfully established in all patients without fatal consequences. In most cases, resolution of hemorrhage required a surgical intervention for ligation of the bleeding vessels and hematoma evacuation. To reduce the probability of such a grave complication, preventive and precautionary measures to be taken before, during, and after implant placement in the anterior mandible are presented. Issues related to the level of surgical experience, fine regional arterial anatomy, radiographic and clinical evaluation of the osseous morphology, angulation and length of implants, and timing of hemorrhage onset are discussed. In addition, airway and bleeding management strategies are provided.