Comparative measurements were made of 144 orthopantomographs in 50 patients
with successful and 94 patients with unsuccessful inferior alveolar nerve block anesthesia.
The results show that the bony lingula is prominent in 28.5% of all patients, or in
56.0% of those with unsuccessful anesthesia. The variables mandibular notch vs. mandibular
foramen (MN-MF) and the anterior ramus ridge vs. mandibular foramen
(ARR-MF) show greater distances in the group of patients with successful anesthesia,
while the variables of posterior ramus ridge vs. mandibular foramen (PRR-MF) and
mandibular angle vs. mandibular foramen (MA-MF) were greater in the group of patients
with unsuccessful anesthesia (p > 0.05). It is concluded that the variability in position
of the mandibular foramen among others may be responsible for an occasional
failure of inferior alveolar nerve block

I. Baučić

J. Keros

P. Kobler

T. Ćabov

Keros, J.

Kobler, P.

Baučić, I.

Ćabov, Tomislav

Repository of the University of Rijeka

Coll. Antropol. 25 (2001) 1: 327–331UDC 611.716:616.314-089.5Original scientific paperForamen Mandibulae as an Indicatorof Successful Conduction AnesthesiaJ. Keros1, P. Kobler2, I. Bau~i}3 and T. ]abov41 Department of Dental Anthropology, School of Dentistry, University of Zagreb, Croatia2 Department of Oral Surgery, School of Dentistry, University of Zagreb, Croatia3 Department of Dental Prosthetics, School of Dentistry, University of Zagreb, Croatia4 Department of Maxilofacial and Oral Surgery, Department of Stomatology,School of Dental Medicine, University of Rijeka, CroatiaA B S T R A C TComparative measurements were made of 144 orthopantomographs in 50 patientswith successful and 94 patients with unsuccessful inferior alveolar nerve block anesthe-sia. The results show that the bony lingula is prominent in 28.5% of all patients, or in56.0% of those with unsuccessful anesthesia. The variables mandibular notch vs. man-dibular foramen (MN-MF) and the anterior ramus ridge vs. mandibular foramen(ARR-MF) show greater distances in the group of patients with successful anesthesia,while the variables of posterior ramus ridge vs. mandibular foramen (PRR-MF) andmandibular angle vs. mandibular foramen (MA-MF) were greater in the group of pa-tients with unsuccessful anesthesia (p > 0.05). It is concluded that the variability in po-sition of the mandibular foramen among others may be responsible for an occasionalfailure of inferior alveolar nerve block.IntroductionNumerous articles and anatomy textsdescribe the anatomic structures rele-vant to successful mandibular anesthe-sia, but failure in this technique still per-sist1–8. The failure involves three majorfactors. The first and the most common isimproper placement of the hypodermicneedle, due to inadequate evaluation ofanatomic landmarks. The second is acces-sory enervation of the mandibular denti-tion, and the third is the marked variabil-ity in position of the mandibular foramen.Panoramic radiographs are commonlyused for screening diagnosis and select-ing the best possible surgical approach8,9.The purpose of this study is to analyzethe relationship between different ana-tomical structures on the inside of thelower mandibular ramus in relation tothe mandibular foramen as referencepoint on orthopantomographs in patientswith successful and unsuccessful inferioralveolar nerve block anesthesia.327Received for publication February 23, 2001.Materials and MethodsThe study was based on a selectedgroup of 50 patients in whom an inferioralveolar block anesthesia was unsuccess-ful (25 women and 25 men aged from 27to 80 years), and the control group of 94subjects (45 women and 49 men rangingfrom 35 to 79 years). Anesthesia was car-ried out by the same dental surgeon usingdirect method with an aspirating syringe(4 cm long, 25 G needle, and 2% Xylocainwith adrenaline 1:200,000). Evaluation ofanaesthetic effects was made on the basisof the adjusted McGill Melzack Pain que-stionnaire (MPQ)10.All subjects were x-rayed using OR-TOCEF (Siemens, Bensheim, Germanyat 80 kVp with Titan 2HS screens (Sie-mens), and X-OMAT L films (Eastman,Kodak, Rochester, N.Y. USA) processed ina RPX-OMAT M8 Kodak processor at 35°C for 90 s. On orthopantomograms thefollowing distances were measured: a) di-stance between the lowest point of themandibular notch and the mandibular fo-ramen (MN-MF); b) distance between theanterior ramus ridge (external obliquelines) and mandibular foramen (ARR-MF); c) distance between the posteriorramus ridge and mandibular foramen(PRR-MF); and d) distance between themandibular angle and mandibular fora-men (MA-MF). The measure points weremarked along with the connecting lines.Measurements were made by using a spe-cially modified electrocaliper (MEBA-Croatia) to an accuracy of  0.01 mm.Data were evaluated in dry mandiblesand panoramic radiographs to study therelation of the narrowest antero-posteriordiameter of the ramus, the shortest dis-tance of the FM to the lowest point of themandibular notch and to the basal planeof the mandible.In order to measure both intra andinter-examiners errors the measure-ments on radiographs were repeated bythe same person at different time blindlyand preferably by others. Descriptive sta-tistical procedures of covariant, multiva-riate and discriminative analyses wereused.ResultsComparative distributions on the ba-sis of successfulness of anesthesia andprominence of mandibular lingula weremarkedly prominent i.e. in 56% of pa-tients with unsuccessful and 13.8% of pa-tients with successful anesthesia. Thedifferences between the groups accordingto sex and age are not statistically signifi-cant. Summarized results of contingencytests for orthopantomographic distribu-tion of quantitative properties in normaldistribution according to success of anes-thesia are presented in Table 1. Accord-ing to Kolmogorov-Smirnov test in thegroup of patients with unsuccessful anes-thesia the distribution of all variablesshow statistically significant departurefrom normal distribution (p > 0.05).Consequently, the two groups werecompared on the basis of Mann-Whitney328J. Keros et al.: Conduction Anesthesia, Coll. Antropol. 25 (2001) 1: 327–331TABLE 1SUMMARIZED RESULTS OF CONTIGENCY TESTS ACCORDING TO SUCCESS OF ANESTHESIASuccessful UnsuccessfulVariables KV P KV PMN-MF 1.74 < 0.01 1.08 > 0.05ARR-MF 1.47 < 0.03 0.88 > 0.05PRR-MF 1.66 < 0.01 1.44 > 0.05MA-MF 21.9 < 0.01 0.99 > 0.05univariate non-parametric test (Table 2).The differences are highly statisticallysignificant for all variables. The indica-tors of differences between MN-MF andARR-MF are greater in the group of pa-tients with successful anesthesia whilevariables concerning the differences be-tween MA-PRR-MF and MA-MF aregreater in the group of patients with un-successful anesthesia (p > 0.05).The comparison between orthopanto-mographic quantitative properties distri-bution and success of anesthesia is shownin Table 2.The distribution of respondents in ca-nonical discriminative function for bothgroups is shown in Figure 1. In general,the discriminative power of the functionmay be considered as a very high one(96.8%), and even slightly higher in thegroup of patients with successful anes-thesia.DiscussionNumeric data regarding the locationof the mandibular foramen are importantwhen a local anesthetic block of the infe-329J. Keros et al.: Conduction Anesthesia, Coll. Antropol. 25 (2001) 1: 327–331TABLE 2COMPARISON BETWEEN ORTHOPANTOMOGRAPHIC QUANTITATIVE PROPERTIES DISTRIBUTIONAND SUCCESS OF ANESTHESIA (MANN-WHITNEY U-WILCOXON RANK SUM W TEST)MN-MFSample average Subjects43.66 50 Group 187.84 94 Group 2144 TotalU W Z Correction908.0 2183.0 6.1704 0.000ARR-MFSample average Subjects55.61 50 Group 181.48 94 Group 2144 TotalU W Z Correction1505.5 1780.5 3.5988 0.0003PRR-MFSample average Subjects113.05 50 Group 150.93 94 Group 2144 TotalU W Z Correction322.5 5652.5 8.6439 0.000MA-MFSample average Subjects92.98 50 Group 161.61 94 Group 2144 TotalU W Z Correction1326.0 4649.0 4.3764 0.000Group 1 = unsuccessfulGroup 2 = successfulrior alveolar nerve is required1–14. Radiol-ogy is the only available noninvasivemethod for diagnosis and treatment plan-ning of major surgical procedures of themandible8,9. In our study comparativemeasurements regarding the location ofthe mandibular foramen and surround-ing anatomic landmarks showed a signifi-cant departure of variables from normaldistribution in the group of patients withunsuccessful anesthesia. So, the distancebetween the mandibular notch (MN) andmandibular foramen (MF) was larger inpatients with successful anesthesia (21.3 1.36) than in patients with unsuccess-ful anesthesia (19.30  1.36). The distan-ce between the anterior ramus ridge(ARR) and mandibular foramen (MF) waslarger in patients with successful anes-thesia (19.37  1.89) than in patientswith unsuccessful anesthesia (18.45 1.73). The distance between the mandib-ular angle (MA) and mandibular foramen(MF) was larger in patients with success-ful (40.67  1.50) than in those with un-successful anesthesia. The distance be-tween the posterior ramus ridge (PRR)and mandibular foramen (MF) was largerin patients with unsuccessful (16.82 1.12) than in those with successful anes-thesia (14.29  1.17). In patients in whomthe distance between PRR-MF and MA-MF (MA-MF > MN-MF) is larger at dis-tinct prominence of the lingula anesthe-sia was observably ineffective.R E F E R E N C E S1. HESTON, G., J. SHARE, J. FROMMER, J. H.KRONMAN, J. Oral. Surg., Oral Med., Oral Path., 65(1988) 32. — 2. NICHOLSON, M. L., Anat. Rec., 212(1985) 110. — 3. ZOGFRAOUS, J. J., E. KAPNIDOI,A. MUTZURI, L. ARDEKIAN, Stomatologiia, 47(1991) 26. — 4. HAYWARD, J., E. R. RICHARDSON,S. K. MALHOTRA, J. Oral Surg., 44 (1997) 837. — 5.KEY, Z. M., Int. J. Oral Surg., 3 (1974) 363. — 6.OGAWA, H. M., TOYAMA, M. A. NEBEYA, NipponDent. Univ. Ann. Public., 24 (1990) 123. — 7. KE-ROS-NAGLI], J., J. PANDURI], D. BUNTAK-KO-BLER, Coll. Antropol., 21 (1997) 203. — 8. GOAZ, P.W., S. C. WHITE: Oral radiology: Principles and in-terpretations. (C. W. Mosby, St. Louis, 1994). — 9.KAFFE, I., L. ARDEKIAN, I. GELERENTER, S. TAI-CHER, J. Oral Surg., Oral Med., Oral Path., 78(1994) 622. — 10. MELZACK, R., Pain, 30 (1978) 191.— 11. RODA, R. S., P. L. BLANTON, QuintessenceInt., 25 (1994) 27. — 12. ROOD, J. P., Brit. Dent. J.,15 (1977) 75. — 13. MALAMED, S. F.: Handbook oflocal anesthesia. (C.W. Mosby, St. Louis, 1990). — 14.WONG, M. K. S., P. L. JACOBSEN, J. Am. Dent.Assoc., 123 (1992) 69.J. KerosDepartment of Dental Anthropology, School of Dentistry, University of Zagreb,Gunduli}eva 5, 10000 Zagreb, Croatia330J. Keros et al.: Conduction Anesthesia, Coll. Antropol. 25 (2001) 1: 327–331Histogram for both groups1 – Group with unsuccessful anesthesia2 – Group with successful anesthesiaFig. 1. Distribution of respondents in canonicaldiscriminative function.FORAMEN MANDIBULE I PROVODNA ANESTEZIJAS A @ E T A KUnutra{nja grana donje ~eljusti ima veliku prakti~nu va`nost u postupcima anes-tezije donjega zubi{nog `ivca. Stoga su na~injene ortopantomografske snimke i obav-ljena usporedna mjerenja protega donje ~eljusti u bolesnika s uspje{nom i neuspje-{nom anestezijom u podru~ju donje ~eljusti. Premda je znano da neuspjeh pri anestezijidonje ~eljusti naj~e{}e nastaje zbog neispravne manipulacije pri izvo|enju anestezije,gdjekad i anatomske zna~ajke mogu biti dodatnim uzrokom ovoj pojavi. Primjerice ubolesnika s uspje{nom anestezijom vrijednosti su IM-MF bile ne{to manje od vrijed-nosti BM-MF, {to je ukazivalo na ni`i smje{taj foramena mandibule, pa stoga u tojskupini nije bilo realne zapreke uspje{nom anestezijskom zahvatu.331J. Keros et al.: Conduction Anesthesia, Coll. Antropol. 25 (2001) 1: 327–331

Foramen Mandibulae as an Indicator of Successful Conduction Anesthesia

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