Area extent anaesthesia from buccal nerve block

Abstract

This study investigated the extent of complete anaesthesia from buccal nerve block. 40 healthy Thai patients (20 males; 20 females) requiring buccal nerve block for surgery were studied. After the buccal nerve was blocked, the buccal mucosa was explored using a sharp probe to map out the extent of anaesthesia. The operation was carried out after inferior alveolar and lingual nerve block. The extent of the anaesthesia was mainly from the retromolar area to the second molar, followed by the first molar to the second premolar, whilst the first premolar to the central incisor was the area least affected. An important finding of this study was that the anaesthetized extent of some patients extended to the anterior region on the same quadrant. This study showed the affected areas of buccal nerve anaesthesia extended through the buccal mucosa from the first premolar to the central incisor in some patients. It can serve as another informative indication for lower anterior surgery.

One of the most commonly used mandibular anaesthetic nerve blocks is the buccal nerve block. It is a useful for reducing buccal soft tissue pain for various dental procedures such as placing a dam clamp, removal of subgingival caries, subgingival tooth preparation, gingival cord retraction and operating on abnormal lesions or infection of the buccal mucosa of the mandible.

The buccal nerve (N. buccalis) is the sensory branch of the anterior division of the mandibular nerve, passing between the lateral pterygoid muscles. It crosses the anterior border of the ramus of the mandible at a similar level to the lower third molar. It distributes to the soft tissue of the cheek .

In the lower posterior region, complete anaesthesia is achieved by a conventional inferior alveolar nerve block. The separated nerve block always requires buccal nerve anaesthesia . Local analgesia in dentistry reports that the buccal nerve innervates the buccal and retromolar mucosa, and the buccal gingival of the lower posterior teeth, including the skin of the cheek. N orton reports that this block anaesthetizes all buccal gingiva opposite the mandibular molars including the retromolar region . M alamed reports the buccal nerve provides sensory innervations to the buccal soft tissue adjacent to the mandibular molar only .

C arter & K een and C oleman & S mith reported the buccal nerve innervated the skin covering the buccinator muscles, cheek, gingival mucosa of the retromolar area and the lower third, second and first molars. H endy et al. reported that the buccal nerve innervates from the buccal gingiva of the lower third molar to the second molar. B lanton & J eske reported on the innervation of the buccal nerve from the gingival mucosa of the lower third molar to the lower canine.

In the authors’ practice, some patients, after complete anaesthesia of the inferior alveolar nerve block, cannot undergo surgical intervention at the lower anterior region on the same quadrant, but can undergo the operation following buccal nerve block. Many studies describe that the buccal nerve innervates the buccal gingiva and mucosa of the mandible for a variable extent from the vicinity of the lower third molar to the lower canine . It is known that high variation occurs in the area of numbness so this study investigated the complete extent of anaesthesia from buccal nerve block.

Materials and methods

40 Thai patients (20 males; 20 females) with no systemic disease and not pregnant, requiring lower posterior surgical intervention were studied ( Table 1 ). The patients were aged 20–60 years with an average age of 30 years (average male age 30 years; average female age 29 years). The study was approved and accepted as a clinical study protocol by the Mahidol University Institutional Review Broad with Protocol No. 2009/139.1905. All examinations and treatments were performed with the signed consent of the patients in the presence of a witness. Written consent was also obtained from the patients for presentation of the study findings.

Table 1
Surgical intervention on the 40 Thai patients.
Sex Type of operation
3M surgery Simple extraction Bone surgery Total
Male 12 8 1 21
Female 13 2 5 20
Total 25 10 6 41

Remark : 3M surgery: third molar surgery. A patient had 2 operations, extraction with bone surgery.

The buccal nerve blocks were injected by the oral surgeon and were tested by the co-operator. The patient rinsed with 0.1% chlorhexidine mouthwash to reduce intraoral microorganisms. The patients were injected with 4% articaine with adrenaline 1:100,000 in the amount of 0.3 ml.

Before the buccal nerve block was injected, the patients were tested for pain sensation. Buccal nerve blocks were injected at the retromolar area by injection at the mucous membrane of the anterior border of the ramus, 1 mm lateral to the most distal molar (third molar area) and in line with the occlusive plane . 1 min after the patients were injected, anaesthesia was detected at each point with a sharp probe calibrated by instrument weight about 200–400 mN (20–40 g). H endy & R obinson reported that the lower forces (<200 mN) were not detected at the anaesthetized point. The anaesthetized points were mapped on the record chart ( Fig. 1 ) with an average utilized time of 7 min.

Fig. 1
Mapping record chart showing the extent of tested points at the horizontal level from the distal retromolar area to the mesial area of the lower central incisor, and the vertical level from the buccal interdental papilla to the buccal mucosa of the mandible.

The completely anaesthetized points were investigated on the horizontal level from the distal retromolar area to the mesial area of the lower central incisor, and the vertical level from the buccal interdental papilla to the buccal mucosa of the mandible by following the mapping record chart. The lower teeth were also tested by Electric Pulp Tester (EPT), and a point at the lingual gingival of the third molar and a point at the lateral side of tongue at the level of third molar were tested by a sharp probe. No area received anaesthesia in the inferior alveolar nerve or lingual nerve from the buccal nerve block. The pattern of each patient’s anaesthetized area was entered on the mapping record chart. After the anaesthetized points had been detected, an inferior alveolar nerve block was undertaken to continue the operative procedure.

Results

The percentages of completely anaesthetized areas are shown in Table 2 and Fig. 2 . No difference in the distribution of area anaesthesia between sexes was found. The highest percentage of completely anaesthetized areas were from the retromolar area to the second molar, whilst the percentage of completely anaesthetized extension was found less in the area from the first premolar to the lateral incisor in males and the central incisor in females.

Table 2
Percentage of patients and average of anaesthetized extents from the buccal nerve block at each level ( n = 40).
Inferior–superior plane (%) Anterior–posterior point (%)
Mandibular Distal of retromolar area Retromolar area Distal of second molar Middle of second molar Distal of first molar Middle of first molar Distal of second premolar Middle of second premolar Distal of first premolar Middle of first premolar Distal canine Middle of canine Distal of lateral incisor Middle of lateral incisor Distal of central incisor Middle of central incisor Mesial of central incisor
Buccal interdental papilla 100 100 97.5 97.5 82.5 72.5 47.5 30 20 20 12.5 12.5 7.5 7.5 2.5 2.5 2.5
Buccal gingiva 100 100 92.5 92.5 72.5 52.5 27.5 17.5 10 10 10 7.5 2.5 2.5 0 0 0
Alveolar mucosa 100 100 95 85 65 25 20 5 5 2.5 2.5 0 0 0 0 0 0
Vestibule 100 100 100 97.5 90 55 35 20 17.5 10 7.5 2.5 2.5 0 0 0 0
Buccal mucosa 97.5 97.5 92.5 92.5 82.5 52.5 27.5 12.5 5 2.5 2.5 0 0 0 0 0 0
total 99.5 99.5 95.5 93 78.5 51.5 31.5 17 11.5 9 7 4.5 2.5 2 0.5 0.5 0.5
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Feb 7, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Area extent anaesthesia from buccal nerve block
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