Transganglionic transport of horseradish peroxidase (HRP) was used to study the patterns of termination of somatic afferent fibers innervating oral and facial structures within the principal nucleus (Vp), nucleus oralis (Vo), and nucleus interpolaris (Vi). The primary trigeminal afferent fibers that innervate the oral cavity supplied by the pterygopalatine, superior alveolar, lingual, buccal, and inferior alveolar branches, as well as the facial skin supplied by the frontal, corneal, zygomatic, infraorbital, auriculotemporal, mylohyoid, and mental branches, were traced in this experiment. The results show that trigeminal afferent nerves that innervate the oral cavity project mainly to the principal nucleus, the rostrodorsomedial part (Vo.r) and dorsomedial division (Vo.dm) of pars oralis, and the dorsomedial region of pars interpolaris, while an extensive overlap of projections is found in the Vo.r, Vo.dm, and rostral Vi. The central processes of fibers innervating the anterior face (i.e., mental, infraorbital, and frontal nerves) terminate in the ventral division of principalis (Vpv), caudal region pars oralis (Vo.c), and ventrolateral Vi, with the largest numbers of terminals being found in the Vpv and Vi. In contrast, the central projection patterns of the corneal, zygomatic, mylohyoid, and auriculotemporal afferents are different from those of other afferent nerves examined, and present a discrete projection to the trigeminal sensory nuclear complex (TSNC). The corneal, mylohyoid, and auriculotemporal afferents mainly project to the restricted regions of principalis and caudal Vi, while zygomatic afferent nerve fibers project to the caudal third of pars interpolaris. The typical somatotopic organization with the face of the mouth open inverted is represented in the rostrocaudal midlevels of the Vpv and caudal pars interpolaris. The Vpd receives topographical projection from primary afferent nerves that innervate the oral structure only, while this projection was organized in a complicated manner. The relationship between the functional segregation and the cytoarchitectonic differentiation of the TSNC is discussed, particularly with respect to this somatotopic organization, combined with the characteristics of projecting cells in the TSNC.

Transganglionic transport of HRP was used to study the patterns of termination of somatic afferent fibers innervating oral and facial structures within the trigeminal nucleus caudalis and upper cervical dorsal horn of the cat. In separate animals, the superior alveolar, pterygopalatine, buccal, inferior alveolar, lingual, frontal, corneal, zygomatic, infraorbital, mental, mylohyoid, and auriculotemporal branches of the trigeminal nerve were traced in this experiment. The organization of the primary afferents innervating the oral structures is not uniform across laminae and at different rostrocaudal levels of the nucleus caudalis. The superior alveolar and pterygopalatine nerves mainly terminate in laminae I, II, and V at the level of the rostral one-third of the caudalis. By contrast, the lingual, inferior alveolar, and buccal nerve terminate in laminae I-V of, respectively, the rostral third, the entire length, and caudal two-thirds of the caudalis. In addition, the lingual, buccal, and pterygopalatine nerves terminate in the dorsal and middle parts of the interstitial islands or pockets of lamina I neuropil extending to the rostral levels parallel to the nucleus interpolaris. Mediolaterally, in laminae I, II, and V of the rostral third an extensive overlap of projections was found between the branches from each trigeminal division, and some overlap was observed between projections from the mandibular and maxillary divisions. On the other hand, the projections of primary afferents innervating the facial structures are arranged in a somatotopic fashion in rostrocaudal and mediolateral axes over the laminae (I-IV) through the nucleus caudalis and upper cervical dorsal horn. Fibers from the perioral and perinasal regions terminate most rostrally in caudalis, and fibers from progressively more posterior facial regions terminate at successively lower levels. A mediolateral somatotopic arrangement was observed, with fibers from the ventral parts of face ending in the medial regions and fibers from the progressively more dorsal parts of the face ending in successively more lateral regions of the medullary and upper cervical dorsal horns. Corneal afferent terminals are concentrated in the outer parts of lamina II at the levels of the rostral parts of the caudal two-thirds of the caudalis and the interstitial islands of lamina I. The maxillary division terminates first at the most caudal level of the caudalis, followed by the ophthalmic division descending as far as the C2 segment and the mandibular division reaching the most caudal level of the C2 segment.(ABSTRACT TRUNCATED AT 400 WORDS)

No abstract

Transganglionic transport of horseradish peroxidase-wheat germ agglutinin conjugate (HRP-WGA) entrapped in hypoallergenic polyacrylamide gel was used to study the patterns of termination of primary afferents that innervate the lower and upper tooth pulps within the trigeminal sensory nuclear complex (TSNC). HRP injections were made into the inferior and superior alveolar nerves in order to compare the central projections of the whole nerve with those from tooth pulps. In addition, the relationship between the distribution of the trigeminothalamic tract cells and the projection sites of the tooth pulp afferents was investigated by injecting HRP into the posterior ventral thalamus. HRP-labeled tooth pulp afferent fibers innervating the lower and upper teeth projected to the subnucleus dorsalis (Vpd) of pars principalis, the rostrodorsomedial part (Vo.r) and nucleus dorsomedialis (Vo.dm) of pars oralis, the medial regions of pars interpolaris, and laminae I, II, and V of pars caudalis. Terminal fields of the lower tooth pulp afferents formed a rostrocaudally running, uninterrupted column from the midlevel of Vpd to the caudal tip of caudalis. In contrast, the column of termination of upper tooth pulp afferents was discontinuous at the Vpd/Vo.r transition, and ended at the more rostral level of the caudalis than that of the lower tooth pulp afferents. The representation of the lower and upper teeth in the TSNC was organized in a somatotopic fashion which varied from one subdivision to the next, although terminal zones of the inferior and superior alveolar nerves overlapped within the Vo.r, Vo.dm, and dorsomedial part of rostral pars interpolaris. The lower and upper teeth were represented in the Vpd, Vo.r, Vo.dm, medial region of pars interpolaris, and laminae I, II, and V, in a ventrodorsal or caudorostral, dorsoventral, lateromedial, dorsoventral, and mediolateral or dorsomedial-ventrolateral sequence, respectively. The smaller, more focal terminal areas of the teeth contrasted sharply with more extensive terminal fields of the alveolar nerves. The HRP injections within the thalamus indicated that neurons in Vpd, the caudal pars interpolaris, and laminae I/V of caudalis, which are subdivisions of TSNC that receive pulpal projections, sent their axons to the ipsilateral and contralateral posterior ventral thalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

BACKGROUND Heat-polymerized acrylic resins are commonly used as denture base, but they have relatively low mechanical properties such as impact strength, transverse strength, and modulus of elasticity that made them susceptible to fracture during clinical application. Various modifications were made to improve the mechanical properties of heat-polymerized acrylic resins, one of them was with the addition of E-glass fiber. We wanted to determine the effect of E-glass fiber (chopped strands of 3 mm size) with 1% and 1.5% weight concentration addition on mechanical properties (impact strength, transverse strength, and modulus of elasticity) of heatpolymerized acrylic resin denture base material and the correlation between them. MATERIALS AND METHODS Ninety samples of heat-polymerized acrylic resin were divided into 9 groups, consisting of impact strength, transverse strength and modulus of elasticity testing group. Each testing group consisting of group without and with addition of 1% and 1.5% E-glass fiber. Impact strength test was performed using Charpy impact tester, while transverse strength and modulus of elasticity were performed using the Universal Testing Machine. After the test, fracture surface of the samples was evaluated and scanning electron microscope view was taken. The effect of E-glass fiber addition to impact, transverse strength and modulus of elasticity on heatpolymerized acrylic resin was analysed with one-way ANOVA statistical test. Pearson Correlation test was then performed to determine the correlation between impact, transverse strength and modulus of elasticity. RESULTS There was an effect of E-glass fiber addition (chopped strands of 3 mm size) with 1% and 1.5% weight concentration to impact strength p=0.0001 (p<0,05); transverse strength p=0,002 (p<0,05); and modulus of elasticity p=0.002 (p<0.05). Pearson Correlation test showed that there was no correlation between impact and transverse strength (r=0.311 and p=0.094) (p>0.05); impact strength and modulus of elasticity (r=0.284 and p=0.128) (p>0.05); and transverse strength with modulus of elasticity (r=-0.044 and p=0.816) (p>0.05). CONCLUSION Addition of 1% and 1.5% E-glass fiber can improve the impact strength, transverse strength, and modulus of elasticity of heatpolymerized acrylic resin denture base and the addition of 1% E-glass fiber can increase a balanced of impact strength, transverse strength, and modulus of elasticity of heat-polymerized acrylic resin denture base.