John R. Zuniga

Chemosensory and somatosensory regeneration after lingual nerve repair in humans

PURPOSE The objective of these studies was to measure the impact of Class IV and V lingual nerve injuries on taste sensitivity and taste receptor density of the anterior tongue before and after microneurosurgical repair. MATERIALS AND METHODS Citric acid detection threshold and suprathreshold magnitude response were measured on the anterior tongue in 12 adult volunteers with unilateral lingual nerve Class IV or V injuries. The right and left sides of the anterior tongue were tested at each session to assess the effect of nerve damage before and 1, 3, 6, and 12 months after repair. Whole-mouth threshold and suprathreshold scales of citric acid taste intensity were measured. The level of sensory impairment was scaled at each test session using a clinical neurosensory test algorithm. Finally, patients completed an 11-item instrument survey that queried the patients perceived expectations of surgery on sensory, taste, and general health before surgery and the patients perceived outcome of surgery at each postrepair session. The patients perceived global satisfaction of surgery was also assessed. RESULTS All 12 patients failed to detect and scale citric acid and had complete or severe sensory impairment on the injured side of the anterior tongue. One year after repair, 50% of the patients demonstrated a substantial increase in the number of fungiform papillae, pores, and ratio of pores/papilla at the same time as they demonstrated the ability to detect and scale citric acid. After repair, patients perceived the greatest improvements in the categories of eating, chewing, feeling, and taste, and the least in speech. CONCLUSION Lingual nerve repair may result in significant changes in somatosensory and chemosensory function and taste bud anatomy on the anterior tongue over time.

Multiphasic effect of morphine on the release of substance P from rat trigeminal nucleus slices

It is generally accepted that morphine acts presynaptically to inhibit substance P (SP) release from afferent terminals in the trigeminal nucleus. Recent studies, however, provide evidence that opioids produce both inhibitory and excitatory effects on SP release which are concentration- and receptor subtype-dependent. In the present study, we have examined a wide range of morphine concentrations on K(+)-evoked SP release from rat trigeminal nucleus caudalis slices. Immunoreactive SP was measured in perfusates. Morphine produced multiphasic effects on K(+)-evoked SP release without affecting basal release. A very low nanomolar concentration (1 nM) suppressed release, higher nanomolar concentrations (100-300 nM) facilitated release, a low micromolar concentration (3 microM) suppressed release, and a higher micromolar concentration (30 microM) facilitated release. These effects were abolished by opioid receptor blockade with naloxone (30 nM). Thus, morphine produces a complex bi-directional modulation of SP release from TNC which is concentration- and possibly receptor subtype-dependent.

A retrospective analysis of lingual nerve sensory changes after mandibular bilateral sagittal split osteotomy

PURPOSE The purpose of this retrospective study was to determine the patient-reported incidence, duration, and perceived deficit in daily activities associated with lingual nerve (LN) sensory changes after bilateral sagittal split osteotomy (BSSO) of the mandible and to compare them with inferior alveolar nerve (IAN) sensory changes in the same study population. MATERIALS AND METHODS Questionnaires were mailed to 316 patients who had undergone BSSO procedures between 1980 and 1993. The patients were queried for perceived sensory changes in the distribution of the IAN and LN; duration of these sensory changes; and alteration in daily activities caused by these sensory changes. The same questionnaire was mailed to 47 patients who had undergone isolated genioplasty (GP) to control for the normal variance of non-BSSO surgery on perceived LN sensory changes. RESULTS Forty-three percent of the BSSO patients and 38% of the GP patients returned the questionnaires. Within the BSSO group, 19.4% reported LN sensory changes, of which 69.3% reported that these changes resolved within 1 year; 88% reported altered daily activities. By comparison, 95.5% reported a perceived IAN sensory change, of which 27.3% reported that these changes resolved within 1 year; 57% reported altered daily activities. Within the GP control group, 11% reported LN sensory changes; none of the reported sensory changes lasted longer than 1 month. CONCLUSIONS A small percentage of patients report LN sensory changes after BSSO. When compared with IAN reported sensory changes, LN sensory changes resolve more frequently and sooner, but they are associated with greater perceived deficits in daily activity. The interpretation of the reported incidence of LN change must be critically reviewed because control subjects also responded positively.

Propofol and Fentanyl Compared With Midazolam and Fentanyl During Third Molar Surgery

PURPOSE The purpose of this study was to measure the safety and efficacy of propofol combined with fentanyl as sedative agents during third molar outpatient surgery. PATIENTS AND METHODS A double-blind, prospective, randomized clinical trial involving 57 patients undergoing removal of third molars under intravenous sedation between November 1994 and December 1995 was performed. Patients randomly received either propofol and fentanyl (P + F, th = 24) or midazolam and fentanyl (M + F, M = 33). Patient demographics, Corah anxiety scores, and physiologic parameters were determined preoperatively. All medications were titrated to the same clinical end point for sedation. Intraoperative physiologic parameters, cooperation, alertness, and pain scores were assessed. Postoperative recovery and degree of amnesia also were determined. RESULTS There were no significant differences in either patient demographics or surgical characteristics between groups. The P + F group was significantly less cooperative than the M + F group. Pain during injection of propofol was a significant adverse side effect. Both groups experienced a small percentage of apneic episodes, but mechanical ventilation was never required. There were no differences in recovery between groups as measured by the Treiger dot test and psychomotor recovery scores. The degree of anterograde amnesia was greater for the M + F group, although the difference was not statistically significant. Sedation was rated good to excellent by the patient, surgeon, and observer, and there were no statistically significant differences between groups. CONCLUSION Propofol appears to be a safe and efficacious drug for use during outpatient oral surgical procedures.

Advances in microsurgical nerve repair

Neurosensory changes in the tongue, floor of mouth, chin, and lip occur because dental procedures (ie, mandibular third molar, implant, preprosthetic, periodontal, endodontic, and reconstructive surgery) are often performed close to the lingual and inferior alveolar nerves. For example, the incidence of such injury ranges between 0.4% and 11.5% following mandibular third molar removal (Table 1). Both specialists and general dentists share in these outcomes. Paresthesia is the major cause of malpractice lawsuits among certain specialists, l2 and the number of such cases may be increasing on account of litigious tendencies within the general population. I3 Because up to 25% of patients with reported nerve injuries fail to recover within 1 or more years of the injury, 4,5*7,‘o,’ ’ the clinicians must inform their patients of the potential risks and consequences of “at-risk” procedures. Clinicians also must be aware of the standards of care to give the best counsel and service to the patient when an injury does occur. Prior to 1982, little information existed regarding the management of the trigeminal nerve injury. Since then, a truly impressive amount of information has been published in the oral and maxillofacial literature addressing technical and clinical advances in the treatment of lingual and inferior alveolar nerve injury.‘4-‘7 Most of this information has been related to the microsurgical reconstruction of nerve injuries; however, in recent years, new strategies for diagnosis and management of such injuries based on the use of conventional and more sophisticated somatosensory (ie, the conscious sensation of the body) tests have emerged.

Surgical and prosthodontic rehabilitation for a patient with aggressive florid cemento-osseous dysplasia: A clinical report

Florid cemento-osseous dysplasia is an extensive form of periapical cemental dysplasia, which usually involves 1 to 4 posterior areas of the maxilla and mandible. The affected area undergoes changes from normal vascular bone into an avascular cementum-like lesion. The lesion is usually benign; however, treatment of a secondary infection of this lesion can be difficult and complicated. This clinical report describes a rare but aggressive secondary infection of this type, which was successfully treated by a combination of complex surgical and prosthodontic procedures, including dental implant therapy.

Treatment of fibrous dysplasia of the mandible with radical excision and immediate reconstruction: Case report

Monostotic fibrous dysplasia of the mandible is an unusual manifestation of the disease that is usually benign, occurs in young individuals, and is managed by conservative curettage or debridement. We present a case of persistent fibrous dysplasia complicated by pain and intraoral bony exposure that was successfully managed by radical resection and reconstruction with a free fibular flap. Although mandibular fibrous dysplasia is preferentially managed conservatively, treatment of this disease has evolved to a point where total excision and immediate reconstruction may be the treatment of choice and offer the best outcome.

Controlled Phase III Clinical Trial of Diclofenac Potassium Liquid-Filled Soft Gelatin Capsule for Treatment of Postoperative Dental Pain

PURPOSE The purpose of the present study was to assess the safety and efficacy of oral diclofenac potassium liquid-filled soft gelatin capsule (DPSGC) that uses ProSorb dispersion technology (Xanodyne Pharmaceuticals, Inc, licensed from AAIPharma, Wilmington, NC), to treat adult patients with acute pain after third molar extraction. PATIENTS AND METHODS In the present multicenter, randomized, double-blind, placebo-controlled trial, patients experiencing a baseline level of pain (≥ 50 mm on a 100-mm visual analog scale within 4 hours after surgery) were randomized to receive a single dose of DPSGC at 25, 50, or 100 mg or placebo. Pain intensity and relief were assessed for 6 hours after dosing. The efficacy endpoints included the summed pain intensity difference, total pain relief, and the median time to the onset of perceptible and meaningful pain relief (using the 2-stopwatch method). RESULTS A total of 249 randomized patients had a significant increase in the summed pain intensity difference and total pain relief values at 3 and 6 hours across all DPSGC-treated groups compared with the placebo group (P < .0001). The onset of perceptible and meaningful pain relief was significantly faster in all DPSGC groups than in the placebo group, including the DPSGC 25-mg group (25 minutes [P = .0002] and 52 minutes [P < .0001] for perceptible and meaningful pain relief, respectively). Significantly fewer patients in the DPSGC groups required rescue medication compared with those in the placebo group (P < .0001). The global evaluation scores were significantly greater for the patients who received DPSGC than for those who received placebo (P < .0001), and more than 65% of DPSGC-treated patients rated the medication as good, very good, or excellent compared with 18% of the placebo-treated patients. DPSGC was generally well tolerated, and no serious adverse events were reported. CONCLUSIONS The results from the present single-dose study of postoperative dental pain suggest that DPSGC offers significant pain relief compared with placebo and that the study medication provided was well tolerated by patients who required pain relief after third molar extraction.

Lingual nerve injury as a complication of rigid fixation of the sagittal ramus osteotomy: Report of a case

This article describes a previously unreported complication of lingual nerve anesthesia and injury as a result of rigid fixation of the mandibular sagittal split osteotomy. The etiology of this injury is discussed and the surgical management using transoral microneurosurgical techniques is described.

Trigeminal ganglion cell response to mental nerve transection and repair in the rat.

PURPOSE Animal studies have suggested that peripheral nerve transection results in substantial loss of ganglion cells and the selective survival of cells based on size. The implications are that subsequent repair of peripheral nerve injuries will be determined by the numerical density and character of the surviving cells. The purpose of this study was twofold: First, to determine the effect of mental nerve transection without repair on trigeminal ganglion cell density and morphology in adult rats, and second, to determine the variation of trigeminal ganglion cell density and morphology after immediate and delayed repair. MATERIALS AND METHODS In the first part of the study, 12 adult male Sprague-Dawley rats had their mental nerves exposed bilaterally (n = 24). Twelve mental nerves were then transected and prevented from regenerating, and the remaining 12 nerves were uninjured. Ninety and 180 days after transection or sham surgery, the trigeminal ganglia were serially cut into 5 microm longitudinal sections along the dorsoventral axis. The volume and volume density of the mandibular mental subdivision containing sensory cells was determined at each section level with point-counting methods. The numerical density and total number of cells was estimated on the same section, using an unbiased three-dimensional stereological probe, the dissector. Cell size and shape determinants were estimated using the dissector and computerized planimetry. In the second part of the study, six rats had the mental nerves transected bilaterally and immediately repaired by microscopic sutures. In six additional rats, the repair was delayed for 90 days. In both groups, the trigeminal ganglia were serially cut at 30, 60, and 90 days post-repair and stereologic estimates of numerical density and histomorphometry were examined using the dissector and computed planimetry. RESULTS In the trigeminal ganglia of the 12 sham-operated animals, the mean number of cells was 20.6 x 10(3) (+/-2.9 X 10(3)). After nerve section, the mean number of cells was 10.88 X 10(3) (+/-0.9 X 10(3)), representing a 47% reduction. The mean volume of the mandibular subdivision cells in the ganglia of the sham surgery animals was 0.3 mm3 (+/-0.05) and 0.22 mm3 (+/-0.04) in nerve-sectioned ganglia, a 38% difference. There were no ganglia cell size or shape differences between the two groups. The mean number of cells in the ganglia of immediately repaired nerves was 10.66 x 10(3)(+/-1.1 X 10(3)), and it was 12.45 x 10(3) (+/-0.9 x 10(3)) after delayed repair. The numerical density was significantly less than in the sham surgery ganglia but not different from that of the transection/no repair ganglia. The weighted mean reference volume of the mandibular subdivision after immediate and delayed repair was similar and was significantly greater than the transection/no repair group, but not different from the sham surgery group. The cell size was slightly larger in delayed-repair ganglia compared with immediate-repair ganglia, but the differences were not significant. There were no significant differences in any of the stereologic estimates when analyzed across treatment time. CONCLUSIONS The results of this study agree with previous reports that peripheral nerve transection produces a substantial loss of nerve cells within specified regions of sensory ganglions. However, the results conflict with evidence that cells survive transection based on size and shape. These findings also indicate that in the adult rat the substantial loss of nerve cells was unaltered by the reconnection of their severed axons. Neither immediate or delayed repair of the transected nerve altered the spectrum of surviving cells based on size or shape. The reestablishment of the mean reference volume of the mandibular subdivision after section and repair suggests that demands made on regenerating axons appear to result in the restoration of ganglionic volume normally lost after axotomy, probably the result of axo