2019, Gettysburg College, Shakyor's review: "Order Dulcolax - Cheap online Dulcolax OTC".
Although the cervical facet joint can be entered from a lateral approach purchase dulcolax pills in toronto medicine holder, using the posterior approach and radiographic guidance allows the operator to directly visualize the position of the spinal canal at all times discount dulcolax 5 mg line medicine 4 the people. If the needle strays medially safe 5 mg dulcolax medications you can take while breastfeeding, the direction can be immediately corrected before dural puncture or injury to the spinal cord. When a needle is placed using a lateral approach, anterior deviation can also lead to penetration of the vertebral artery; the vertebral artery is protected by the facet column when a posterior approach is used. However, there is no evidence apposition to the lateral aspect of the atlantoaxial joint, that injection of the atlantoaxial joint can produce any- while the dorsal root ganglion and spinal nerve of C2 thing more than modest, short-term pain reduction. At lie directly over the medial and midportion of the joint the same time, recent reports of massive stroke following (Fig. Block of the atlantoaxial joint is per- intra-arterial injection of particulate steroid during the formed in a manner similar to that described for intra- conduct of atlantoaxial injection have appeared (see Fig. Thus many practitioners have abandoned the use of The patient in positioned prone with the head in a neu- this technique entirely. The technique is discussed here tral position and the mouth opened as far as possible to briefly to make readers aware of the relevant anatomy that allow good visualization of the lateral elements of C1 and makes intra-articular injection of the atlantoaxial joint C2 in the anteroposterior projection (Fig. The vertebral artery lies in close To avoid contact with the C2 spinal nerve medially and 88 Atlas of Image-Guided Intervention in Pain Medicine A Odontoid process of C2 C2C2 Spinous processes Mandible C3 C4 Inferior articular Needle tip process of C3 in posterior C5 aspect of C3/4 facet joint Inferior articular Superior articular process of C4 process of C4 on contralateral side B C Figure 7-9. Three-dimensional reconstruction computed tomography of the cervical spine as viewed in the lateral projec- tion. B: Lateral radiograph of the cervical spine during intra-articular cervical facet injection. A 22-gauge spinal needle is in place in the posterior aspect of the C3/C4 facet joint. Once the surface of the joint space is contacted, a contrast under live fluoroscopy with or without digi- lateral radiograph is obtained (Fig. It is imperative that intra-arterial ing efficacy of particulate versus nonparticulate steroid Chapter 7 Facet Injection: Intra-articular Injection, Medial Branch Block, and Radiofrequency Treatment 89 for atlantoaxial joint injection. Nonetheless, given the Thoracic Intra-articular Facet Injection close proximity of the vertebral artery and the potentially catastrophic consequences of intra-arterial injection, Positioning strong consideration of use of nonparticulate steroid Thoracic intra-articular facet injection is not com- should be given, for example, 4 mg of dexamethasone monly employed. Even with steep A Needle tip in left posterolateral Approximate atlanto-axial (C1/2) course of facet joint vertebral artery C1 C2 Approximate location of dorsal root ganglion and C2 spinal nerve Inferior margin of B C mandible, mouth open Figure 7-10. A: Bony anatomy relevant to cervical intra-articular facet injection of the atlantoaxial (C1/C2) facet joint. Three-dimensional reconstruction computed tomography of the cervical spine as viewed in the oblique projection. Inset illustrates the position of the vertebral artery; the approximate position of the C2 dorsal root ganglion and spinal nerve is shown. A 22-gauge spinal needle is in position in the lateral third of the left atlantoaxial facet joint. A 22-gauge spinal needle is in position in the posterior atlantoaxial facet joint. E: Labeled lateral image showing the approximate position of the vertebral artery. The patient is positioned prone without the image intensiﬁer resting against the patient’s with the head turned to one side. This angle allows visualization of structures adja- 50 to 60 degrees in a caudad direction from the axial plane cent to the facet joint from which the position of the joint (Fig. Chapter 7 Facet Injection: Intra-articular Injection, Medial Branch Block, and Radiofrequency Treatment 91 A Transverse Spinous processes T10T10 processes T111 Pedicles T1T12 Inferior articular process of T11 B C Figure 7-12. Three-dimensional reconstruction computed tomography of the thoracic spine as viewed from the posterior approach used for thoracic intra-articular facet injection. Because of their steep angle, the thoracic facet joints cannot be seen directly but must be inferred from the position of adjacent structures. The superior aspect of each joint (inferior articular process) lies posteriorly (arrows), directly over the inferior aspect of the joint (superior artic- ular process). This position can be inferred by following the inferior margin of the lamina from the spinous process laterally. Using concen- The needle tip is advanced toward the inferior aspect of the trated steroid (40 or 80mg permL) allows 1:1 mixture joint (Figs. Block Technique The skin and subcutaneous tissues overlying the facet Lumbar Intra-articular Facet Injection joint where the block is to be carried out are anesthe- Positioning tized with 1 to 2mL of 1% lidocaine. The thoracic level is easily identiﬁed by counting upward from the T12 level, The patient is positioned prone with the head turned to where the 12th and lowest rib joins the T12 vertebra (see one side. This angle allows direct visualization of the tissues in a plane that is coaxial with the axis of the facet joint (Figs. The needle is adjusted to remain coaxial and advanced toward the inferior margin of the joint space Block Technique (see Fig. Because of the joint’s steep angle, the needle can be advanced only into the inferior- and pos- The skin and subcutaneous tissues overlying the facet joint terior-most extent of the joint (see Fig. Lateral where the block is to be carried out are anesthetized with radiography is difﬁcult to interpret due to the overlying 1 to 2 mL of 1% lidocaine. The needle is position has been conﬁrmed, a solution containing ste- adjusted to remain coaxial and advanced toward the joint roid and local anesthetic is placed. The facet joint itself holds only lim- of methylprednisolone acetate or the equivalent should be ited volume (typically <1. A 22-gauge spinal needle is advanced in the sagittal plane overlying the facet joint with 60 to 70 degrees of caudad angulation from the axial plane. Chapter 7 Facet Injection: Intra-articular Injection, Medial Branch Block, and Radiofrequency Treatment 93 Facet joint Costotransverse Dorsal joint Facet joint root ganglion Costovertebral (T8) joint T8 Posterior T9 primary ramus of spinal nerve Anterior Lung primary T8 T9 ramus of spinal nerve T10 Sympathetic chain AortaAorta Esophagus Figure 7-14. Axial panel (right): The needle is advanced in the sagittal plane to enter the posterior and inferior aspect of the facet joint. Sagittal panel (left): Because of the steep angle of the thoracic facet joints, the needle tip will only penetrate the posterior- and inferior-most aspect of the joint. Three-dimensional recon- struction computed tomography of the thoracic spine as viewed in the lateral projection; the bony elements of the right lateral hemithorax have been removed to allow better visualization of the spine. The thoracic superior articular processes can be identiﬁed in the lateral radiograph by following the contour of the superior end plate of each vertebra posteriorly toward the intervertebral foramen. The inferior aspect of each joint lies posteriorly (arrows), where the transverse process joins the superior articular process. Nonetheless, intra-articular injection of Once needle position has been conﬁrmed, a solution con- contrast is commonly carried out at the lumbar levels. A total dose articular space is z-shaped, with the superior recess extend- of 80mg of methylprednisolone acetate or the equivalent ing slightly lateral to the axis of the articular surfaces, and should be divided over all the joints to be injected, but the inferior recess extending slightly medial to the axis of more than 40mg per joint is probably unnecessary. The C-arm is angled 25 to 35 degrees from the sagittal plane parallel to the axial plane. Chapter 7 Facet Injection: Intra-articular Injection, Medial Branch Block, and Radiofrequency Treatment 95 A Pedicles Laminae Transverse processes Needle with tip L4L44 projected directly over hub within the Spinous L4/5 facet joint processes Iliac crest L5 Superior articular Inferior articular process of S1 process of L5 Posterior sacral Sacrum foramen of S1 B C Figure 7-17. Three-dimensional reconstruction computed tomography of the lumbar spine as viewed in the left oblique projection used for needle insertion. B: Left oblique radiograph with needle in ﬁnal position for right L4/ L5 intra-articular facet injection. The needle’s hub is projected directly over the tip (coaxial) and lies directly over the L4/L5 facet joint.
Regional control was sality purchase dulcolax uk medicine shoppe locations, lingual nerve numbness buy cheap dulcolax 5 mg symptoms ptsd, postoperative achieved in 90% and distant control in 100% dulcolax 5mg without prescription medications a to z, trismus, dysgeusia, and cervicalgia. In a larger, If en bloc concurrent resection of primary and multi-institutional study of oncologic outcomes cervical lymph nodes is performed, as opposed to of 410 patients, 2-year locoregional control in staged neck dissection, the risk of creating a fs- tonsillar cancers was 97. The 2-year overall tula to the neck is closer to 30%, and some recon- survival was 95. If a small connection is created (<1 cm), primary closure, tissue sealant, and cervical drain may be suff- 7. If a larger defect is created, primary closure can be attempted, and local mus- Dysphagia is a frequently cited adverse effect of cle coverage using the digastric, mylohyoid, and/ treatment for tonsillar cancer. At 18 months after sur- dard monopolar and bipolar cautery tools, hemo- gery, nearly all patients continue to take an oral stasis clips, and the use of a capable bedside diet without the use of a feeding tube . Anderson Dysphagia Inventory) scores than Indeed, since 2009, evidence from the those patients treated with primary chemoradia- National Cancer Data Base shows that surgi- tion at 6 and 12 months after surgery. Although References there are reports of its use in more advanced tumors, one of the major benefts of utilizing 1. Primary surgery as robotic surgery is that it obviates the need for treatment for early squamous cell carcinoma of the tonsil. Kelly K, Johnson-Obaseki S, Lumingu J, Corsten invasive robotic surgery following chemoradiation M. Oncologic, functional and surgical outcomes of therapy due to the extent of recurrence . Robotic surgery for oro- lenging in minimally invasive robotic approaches pharyngeal cancer. Electrocoagulation in epitheliomas of the vessels are likely to be encountered in the oro- tonsils. Transoral laser microsurgery for squa- 7 Transoral Robotic Surgery for Tonsillar Cancer 59 mous cell carcinoma of the base of the tongue. Transoral robotic surgery robotic surgery for oropharyngeal squamous cell carci- alone for oropharyngeal cancer: an analysis of noma: a prospective study of feasibility and functional local control. Demonstration of transoral logic results of transoral robotic surgery for oropha- surgery in cadaveric specimens with the medrobotics ryngeal squamous cell carcinoma. Chemoradiation has resulted in equivalent Transoral approaches were technically challeng- oncologic control rates to those of open resection ing due to limitations in visualization and the techniques . With the success of chemoradia- acquisition of hemostasis, frequently resulting in tion techniques and the aforementioned chal- incomplete resections. Open approaches were lenges associated with older transoral and open looked upon unfavorably due to the relatively techniques, surgery was mostly relegated to high morbidity associated with lip split and man- application in salvage scenarios. In spite of its dibulotomy required for access, in addition to the increased utilization, chemoradiation has its need for tracheotomy and gastrostomy tubes. While these tri- and healthier patients than their historical coun- als were designed to demonstrate the effcacy of terparts whose tumors were due to tobacco and organ preservation therapy in the larynx, the alcohol exposure. After offce examination and maintaining excellent oncologic control and the acquisition of axial imaging techniques, improving long-term functional outcomes. Technological improvements, particularly adequate exposure can be obtained to perform a in the feld of transoral robotic surgery, have transoral resection. Following a staging exami- resulted in superior visualization due to innova- nation, the patient can be scheduled for resection tions in the optics of the endoscopes, tremor fl- of both the primary tumor and the draining tration, motion scaling, and increasingly agile regional lymphatics. When compared to beyond the scope of this chapter, surgeons have prior open techniques, transoral approaches offer the options of either staged or concurrent neck several benefts including decreased morbidity, dissection often combined with ligation of the decreased blood loss, shorter operative times, and external carotid arterial supply to the area of the decreased hospital stay . Consequently, there has been from the superior thyroid artery which often a trend in multiple centers nationally toward a supplies the vallecula. Oncologic contraindications include The new algorithm of applying surgery up front T4b disease, fxation to the retro- or parapharyn- in the treatment of tongue base cancers utilizes geal tissues, unresectable neck disease, and dis- neck dissection as well as transoral resection of tant metastatic disease. Patients with tongue base within the tongue base include the need to spare cancers are frst assessed with the in-offce the contralateral lingual vascular pedicle. In examination, including a fexible fberoptic order to preserve swallowing function, tumors examination and palpation of the tongue base that extend beyond 50 % of the tongue base are lesion to assess the extent of the tumor. Accurate considered poor surgical candidates due to the understanding of the extent of the tumor requires risk of future aspiration risks. If none of as it relates to the lingual pedicle as well as the these conditions exist, then the patient is consid- ability to assess the extent toward the midline of ered a candidate for resection. After adequate visualization is obtained, the endotracheal tube The patients should be intubated by an experi- is secured between the contralateral oral tongue enced anesthesiologist often with the use of a and the retromolar trigone with a silk suture that GlideScope or other fberoptic approaches as we keep long and attached to a clamp so it is not injury to the tongue base during intubation may forgotten about during extubation (Fig. A wire-reinforced endotracheal tube is required that should be secured contralaterally; our preference is to sew the tube to the contralateral melolabial crease to ensure it is not dislodged during the resection. Our preference is to give antibiotic prophylaxis with broad-spectrum anti- biotics that cover anaerobes within the upper aerodigestive tract. Our protocol includes the use of Unasyn in penicillin-tolerant patients and clindamycin in penicillin-allergic patients. A tongue stitch is applied anteriorly to retract the tongue anteriorly and aid in place- ment of the retractor. Adequate exposure includes visualiza- tion of an acceptable cuff of tongue base anteri- Fig. View from head of bed with intubated orly to ensure a clear margin as well the epiglottis patient in suspension with robotic arms in proper to aid in the medial and inferior incisions through orientation, demonstrating suture securing the vallecula. Our approach has always been have the tendency to carry their anterior cut too to perform a standard resection in the same manner superfcial and risk transecting the specimen in each time to make the resection easier to replicate the vallecula. While other the ipsilateral robotic arm, while the Maryland surgeons may approach the resection in a different dissector is placed on the contralateral arm. It is important to carefully The assistant will require both right and left note the extent of the preoperative imaging and curved manual clip appliers with both small and utilize the excellent optics of robotic system to medium clips. Finally, a suction Bovie may assist assess that tissue is clear of disease during dissec- in hemostasis. Exposed view of the tongue base after proper retractor placement 8 Transoral Robotic Surgery for Base of Tongue Cancer 65 Next, the lateral cut is performed through the close margin on exam, our approach is to apply inferior aspect of the tonsil and constrictor with methylene blue to the defect and excise an additional the exact location based upon the lateral extent of cuff of mucosa and deep tongue base muscle. The incision is carried through to the stylo- The specimen is then carried directly to glossus. Next, the styloglossus is divided by ele- pathology where the surgeon orients the speci- vating the muscle with the spatula tip and grasping men for the pathologist and observes the inking with Maryland prior to cutting on the Maryland of the margins. The lingual artery is identifed deep cally and horizontally to assess the deep margin. Throughout the case, The incision is carried deep into the tongue base hemostasis is paramount. It is obtained with use of musculature and taken through to the inferior the robotic cautery and clips applied by the bedside extent of the vallecula at the epiglottis. Occasionally, suction Bovie electrocautery posterior incision is made along posterior/inferior can be helpful as well. The defect is aggressively extent of the vallecular mucosa, often sacrifcing irrigated and Valsalva maneuvers are performed. In terms of reconstruction, ideal scenario, the epiglottis will be visualized to the tongue base is left to granulate on its own, while ensure cut is carried through the vallecular mucosa a small pharyngoplasty may be performed as needed in the proper location so that the malignancy is with horizontal mattress Vicryl sutures through the not transected prematurely (Fig. Intraoral representation of location representation of exposed epiglottis with mucosa of lingual artery after division of styloglossus along lingual aspect divided after completing the musculature medial incision 66 J.
Universal (e) triangular ridge of the buccal cusp; (f) distal tooth numbers for teeth in order: 2 cheap dulcolax 5mg otc treatment yeast infection home,3 generic 5 mg dulcolax free shipping silent treatment,4 discount dulcolax uk medicine z pack,5,6,7,8; cusp ridge of the mesiobuccal cusp; (g) mesiobuccal 25 for central incisor, 26,27,28,29,30,31. The groove; (h) distobuccal groove; (i) distal cusp tip; correct numbers using the International System are (j) transverse ridge made up of the triangular 17,16,15,14,13,12,11; 41 for central incisor, ridges of the distobuccal cusp and the distolingual 42,43,44,45,46,47. If you were observing the faciolingual dimension of (or letter) would they be talking about? Which ridges surround the perimeter of the anatomic crown occlusal surface (occlusal table) of a two-cusped b. Where do lingual cusps of maxillary teeth occlude location of the greatest bulge (crest of curvature or in ideal class I occlusion? Which space(s) contain(s) the part of the gingiva with two cusps (one buccal cusp and one lingual known as the interdental papilla? Ideal class I occlusion involves an important first permanent molar relationship where the mesiobuccal cusp of the maxillary first molar is located within the a. Using good light source (like a small flashlight), a large mirror (magnifying if possible), and a small, clean disposable dental mirror (which can be purchased from most drug stores), evaluate the facial and lingual surfaces of a maxillary right lateral incisor in your own mouth. Describe the tooth in as much detail as possible trying to use as many of the terms presented in this chapter as possible. For example, “There is a pit on the lingual or palatal surface in the cervical or gingival third in the lingual fossa adjacent to the cingulum that is deeply stained. Repeat this exercise for the maxillary left lateral incisor, the maxillary right central incisor, and the maxil- lary left central incisor. This exercise is designed to assure student mastery of the three common systems used to identify teeth. In the chart that follows record the universal tooth number to identify each of the four permanent first molars. In this chart, record the correct answers for each of the four permanent central incisors. Oral embryology and microscopic anatomy, a textbook Blackwell Scientific Publications, 1981:133. Woelfel’s original research on a sample of 4572 extracted teeth obtained from den- on tooth dimensions were used to draw conclusions tists in Ohio from 1974 through 1979 are presented throughout this book. They taper When discussing traits, the external morphology of (narrower) from the widest mesiodistal areas of proxi- an incisor is customarily described from each of five mal contact toward the cervical line, and are therefore views: (a) facial (or labial), (b) lingual (tongue side), narrowest in the cervical third and broader toward the (c) mesial, (d) distal, and (e) incisal. Incisor First, consider the class traits of incisors, that is, traits crown contact areas (greatest height of contour proxi- that apply to all incisors. Incisors usu- central, which is at the same level as the mesial due to its ally have two shallow vertical developmental depres- symmetry (Appendix 1e). Subtle shading highlights these depressions tral slopes cervically (appears shorter) toward the distal. The three lobes also con- Finally, the cervical line curves toward the apex in the tribute to three rounded elevations on the incisal edge middle of the facial (and lingual) surfaces (Appendix 1l). Finally, remember that (become more narrow) from the cervical line to the a fourth (lingual) lobe forms the lingual bulge called a apex (Appendix 1f). Note that there may be roots, which are not as likely to bend; this bend is more exceptions to the general incisor traits presented here, often toward the distal (Appendix 1h). Both teeth are “shovel shaped” due to their deep lingual fossae along with pro- nounced lingual marginal ridges and cingula. Both teeth have three rounded protuberances on their incisal edge called mamelons (arrows). The right tooth has a stained pit on the incisal border of the cingulum where caries can penetrate without being easily noticed. The labial outline is broader and less curved than the Incisor crowns, when viewed from the lingual, have a convex lingual outline (Appendix 1r). Marginal ridges narrower lingual surface because the mesial and dis- converge toward the cingulum (Appendix 1k), and the tal surfaces converge lingually (best appreciated from crown outline tapers from proximal contact area toward the incisal view, Appendix 1j). The mesial and distal the cingulum (Appendix 1j), resulting in a narrower marginal ridges converge toward the lingual cingulum lingual than labial surface. They have these arch traits that can be used to distinguish man- a facial outline that is more convex cervically than dibular incisors from maxillary incisors. The lingual height of contour is also look more alike and are more nearly the same size in the cervical third, on the cingulum, but the contour in the same mouth, compared to greater differences of the incisal two thirds of the lingual surface is concave between maxillary central and lateral incisors (Fig. Therefore, the Mandibular incisor crowns are flatter than maxil- lingual outline is S-shaped, being convex over the cingu- lary incisor crowns on the mesial and distal surfaces lum and concave from the cingulum nearly to the incisal (Appendix 2q) and have contact areas located closer to edge (Appendix 1p). The concave portion of the lingual surface on the maxillary anterior teeth is a most impor- tant guiding factor in the closing movements of the lower jaw because the mandibular incisors fit into this concav- ity and against marginal ridges of the maxillary incisors as maximum closure or occlusion is approached. The resultant curve is greater on the mesial sur- face than on the distal (compare the mesial and distal views in Appendix 1o). Finally, mandibular incisor roots are longer in propor- tion to their crowns than are maxillary incisor roots. Incisal ridges of mandibular incisors are usually posi- tioned lingual to the mid-root axis line, whereas the incisal ridges of maxillary incisors are more often on or labial to the root axis line (best seen from the proximal views on Appendix 2o). Attrition (wear) on the incisal ridges of incisors that occurs when shearing or incising food results in tooth wear that is in a different location on maxillary incisors compared to mandibular incisors (Fig. This wear occurs when the labial part of the incisal edges of mandibular incisors slides forward and downward while contacting the lingual surface and part of the incisal edge of opposing maxillary incisors. Proximal view of the normal relationship of incisors when posterior teeth are biting tightly together. The arrow dibular incisors are more on the labial slope of the incisal indicates the direction of movement of mandibular incisors when edge, sloping cervically toward the labial. In contrast, fac- the mandible moves forward (protrudes) with the incisors touching ets on maxillary incisors occur more on the lingual slope until they align edge to edge. The resultant wear pattern or facets on of the incisal edge, sloping cervically toward the lingual the incisal edges of maxillary incisors occurs more on the lingual fossa and may occur on the lingual marginal ridges. Mandibular incisor crowns are relatively wider arch traits that distinguish maxillary from mandibu- faciolingually than mesiodistally compared to maxil- lar incisors and see how many of them can be used lary central incisors, which are wider mesiodistally to differentiate the rows of maxillary and mandibu- (Appendix 2h). Mandibular incisor crowns also have lar incisors from various views in Figures 2-5, 2-6, smoother lingual surfaces with less prominent anatomy 2-8, 2-10, and 2-13 through 2-15 and 2-17. Maxillary central and lateral incisors, labial views, with type traits that distinguish maxillary central from lateral incisors, and traits that distinguish right and left sides. Maxillary central and lateral incisors, lingual views, with type traits that distinguish maxillary central from lateral incisors, and traits that distinguish right and left sides. If possible, repeat this on a model with • Describe the type traits that can be used to distin- one or more maxillary incisors missing. Normally, the labial surface of sors are compared for similarities and differences. Mamelons, facial, lingual, proximal (including mesial and distal), and particularly labial depressions, are less prominent and incisal.
This is where we place this interproximal space is referred to as the cervical or the dental floss before passing it through the contact area gingival embrasure purchase generic dulcolax from india treatment associates. The lingual embrasure is ordinarily larger than the Embrasures surrounding well-formed proximal facial embrasure because most teeth are narrower on contact areas serve as spillways to direct food away the lingual side than on the facial side order dulcolax 5 mg medications before surgery, and because from the gingiva discount generic dulcolax canada treatment zinc poisoning. When the embrasures are incor- their contact points are located facial to the faciolin- rectly shaped (as with a poorly contoured dental res- gual midline of the crown. The triangles in Figure 1-40 toration), or when there is a space between the teeth, illustrate these embrasure spaces. This food from the occlusal surface or incisal edge to the contact impaction is not only an annoyance, but it can contrib- areas and is narrow faciolingually on anterior teeth but ute to the formation of dental decay and periodontal broad on posterior teeth. The importance of proper occlu- teeth are labial to the incisal edges of mandibular sion cannot be overestimated. These topics will be • Relationship of posterior teeth: The maxillary pos- covered in much more depth later in this book. The terior teeth are positioned slightly buccal to the man- arrangement of teeth within the dental arches (align- dibular posterior teeth (Fig. Ideal tooth relationships were described and clas- • The buccal cusps of the mandibular teeth rest in sified in the early 1900s by Edward H. Dental stone casts with adult Anteroposterior curve teeth fitting together in the maximum intercus- (curve of Spee) pal position (tightest fit). Notice that, from this view, each tooth has the potential for contacting two opposing teeth except the maxillary third molar. The vertical red line marks the relation- ship of first molars in class I occlusion: the mesiobuccal cusp of the maxillary first molar occludes in the mesiobuccal groove of the mandibular first molar. The left cheek has been drawn back to reveal how each of these maxillary teeth occlude with two opposing mandibular teeth. Maxillary and mandibular teeth of the perma- nent dentition are in the maximum intercuspal position. Observe the interproximal spaces filled with the interdental papillae groove (the mesial of two buccal grooves) on the between each pair of teeth. Note how the incisal edges and cusp tips of maxillary teeth overlap and hide the incisal edges and cusp ship of first molars (the first permanent teeth to tips of the mandibular teeth, and how the wide maxillary central erupt) is a key factor in the definition of class incisors overlap not only the mandibular central incisor, but also I occlusion. For example, the distal surface of the maxil- lary first molar in Figure 1-41 is posterior to the distal surface of the mandibular first molar and Buccal surface therefore occludes with both the mandibular first Linqual surface of maxillary of maxillary molar and second molar. Exceptions include the man- molar L B dibular central incisor which, due to its size and L B location, only occludes with the maxillary central incisor (as seen in Fig. As a gen- premolars with one buccal and one lingual cusp, also eral rule, the facial portion of incisors, canines and pre- develop from four lobes: three facial lobes forming the molars forms from three lobes, and the cingulum area facial portion, and one lingual lobe forming the cingu- or lingual cusp(s) each form from one lobe. Therefore, lum area on the canine or the one lingual cusp on the incisors develop from four lobes: three facial lobes premolar. Drawings A, B, and C show the facial, mesial, and incisal views of a maxillary central incisor that, like all anterior teeth, forms from four lobes. Mamelons may appear on the incisal edge of newly erupted incisors, an indication of the three labial lobes. Drawings D and G are the mesial and C occlusal view of a two-cusped premolar that also forms from four lobes. As with anterior teeth, the facial cusp forms from three lobes, and one lingual lobe forms the lingual cusp. The divisions between the facial and lingual lobes are evidenced by the marginal ridge developmental grooves. Drawing E is a mandibular first molar with five lobes, three buccal, and two lingual, which is one lobe per cusp. Drawing F is a maxillary first molar with three larger lobes and one smaller lobe, or one per cusp. A very small fifth (Carabelli) cusp, when present, may form from a part of the large mesiolingual lobe, or may form E F G from a separate lobe. Three very subtle molars have as few as three cusps and form from three vertical ridges separated by two subtle depressions pro- lobes. Two types of tooth anomalies, peg-shaped maxil- vide evidence that three lobes form the facial surfaces lary lateral incisors and some extra teeth (also called of anterior teeth and premolars. As a general rule, each molar cusp forms from one Guidelines for determining the number of lobes that lobe. For example, maxillary or mandibular molars form each tooth are presented in Table 1-5. Look at the formulas Sketch a tooth and adjacent gingiva in cross sec- for animals in Table 1-6 and note that cows have no tion (similar to Fig. They have three upper structures: enamel, dentin, cementum, pulp cav- and three lower premolars on each side. Did you know ity, pulp chamber, apical foramen location, den- that dogs have twice as many premolars as humans if tinoenamel junction, cementoenamel junction, you include uppers and lowers, as well as the right and dentinocemental junction, periodontal ligament left sides? Did you know that the tusks on an elephant space, alveolar bone, gingiva, gingival sulcus, are maxillary central incisors? The size is needed to provide mechani- cal support for the tusks (one third of their length is embedded in the skull) and the enormous molars. Each molar weighs about 9 pounds and is nearly a foot long mesiodistally on the occlusal surface. They have very hard, bright orange enamel on the labial surface and much softer exposed dentin on the lingual surface. The posterior teeth have flat, rough edges on the occlusal surface, and they stop growing at 2 years of age. There is a large diastema immediately posterior to the incisors, and flaps of skin fold inward and meet behind the incisors to seal off the back part of the mouth during gnawing. Also, their small body can store only enough food for 1 to 2 h, so they must feed almost con- tinually. The vampire bat has large canines, but its highly specialized upper incisors, which are V-shaped and razor-edged, are what remove a piece of the victim’s skin. The bat’s saliva contains an anticoagulant, and its tongue rolls up in a tube to suck or lap the exuding blood. Some vertebrates do not have any teeth (complete anodontia) but have descended from ancestors that possessed teeth. Birds have beaks but depend on a gizzard to do the grinding that molars would usually perform. Turtles have heavy jaw coverings, which are thin edged in the incisor region and wide posteriorly for crushing. The duck-billed platypus has its early-life teeth replaced by keratinous plates, which it uses to crush aquatic insects, crustaceans, and molluscs. The whale- bone whale and anteaters also have no teeth, but their diets do not require chewing. Identify the teeth visible in Figure 1-46A using the confirm the correct method for identifying each of Universal Numbering System. Then drop to the 3,4,5,6,7,8,9,10,11,12,13,14; then 19 for man- mandibular central incisor and continue numbering dibular first molar, 20,21,22,23,24,25,26,27,28, back to the mandibular second molar. The correct numbers using the International your responses to the answers that follow.