Taibah University College of Dentistry PDF

1446 TaibahTaibah University University ‫طـيبــــة‬ ‫طـيبــــة‬ ‫جـامعــــة‬...

1446 TaibahTaibah University University ‫طـيبــــة‬ ‫طـيبــــة‬ ‫جـامعــــة‬ ‫جـامعــــة‬ College College of Dentistry of Dentistry ‫األسنان‬ ‫األسنان‬ ‫طبطب‬ ‫كليةكلية‬ Department Department of Substitutive of Substitutive DentalDental ‫االستعاضية‬ ‫االستعاضية‬ ‫االسنان‬ ‫االسنان‬ ‫علوم‬‫علوم‬‫قسمقسم‬ Sciences Sciences Anatomical Landmarks Dr. Rania M. Moussa Assistant Professor Removable Prosthodontics Faculty of Dentistry, Taibah University Office Hours: Tuesday 12:00-1:00 Thursday: 12:00-1:00 Office 316 email: [email protected] Dr. Rania M. Moussa Intended learning outcomes: by the end of this lecture, you will be able to: Discuss the significance of the extra oral anatomical landmarks in complete denture construction Identify maxillary border structures. Recognize maxillary denture foundation area and stress bearing areas. Discuss the clinical significance of the maxillary anatomical landmarks. Identify maxillary relief areas and causes of their relief. 1446 Anatomical Introduction: landmark is: A recognizable anatomical structure used as a point of reference. Dr. Rania M. Moussa 1446 Anatomical Landmarks Extra oral Anatomical landmarks Maxilla Intra oral Mandible Dr. Rania M. Moussa 1446 A- Extra Oral Anatomical Landmarks Dr. Rania M. Moussa 1446 A- Extra Oral Anatomical Landmarks Inter pupillary line Ala Tragus Line Naso – Labial sulcus Modiolus Philtrum Angle of the mouth Labiomental sulcus Vermillion border Dr. Rania M. Moussa 1446 B- Intra Oral Anatomical Landmarks Introduction: 1- Maxillary 2- Mandibular Dr. Rania M. Moussa Intra oral anatomical landmarks may be: The structures which limit the extension of the maxillary and mandibular complete dentures and are called border-limiting areas. Tissue areas or regions in the maxillary and mandibular edentulous foundations, which are better suited to bear the stresses of mastication and are called stress bearing areas. Tissue areas which are not quite suited to take up stresses, either due to their anatomy or due to vital structure that lie beneath them and are called stress relief areas. 1446 A- Maxillary Anatomical Landmarks Dr. Rania M. Moussa  Border or limiting structures The functional anatomy of the mouth that determines the extension and thickness of the denture borders. I- Border or Limiting structures: 1. Labial frenum. 2. Labial vestibule. 3. Buccal frenum. 4. Buccal vestibule. 5. Hamular notch. 6. Vibrating line 1-Labial frenum: It is a fibrous band covered by mucous membrane at the midline, may be single or multiple. Labial Extending from the mucous lining of the lips frenum towards alveolar mucosa. Contains no muscle fibers and has no action on its own. Significance: A labial notch must be provided in the denture, that must be wide enough and just deep enough to allow the frenum to pass through and move freely. Improper labial notch will cause pain and dislodgement of the denture Labial notch 2- Labial vestibule(sulcus) Extends from labial frenum to buccal frenum bilaterally. It is occupied by the labial flange of the denture. Labial vestibule Height of the labial flange is determined by the reflection of mucolabial fold. Labial Flange  3- Buccal frenum: Fold of mucous membrane in the region of the premolars. Single or multiple, band or Buccal frenum broad fan shaped. Significance: Buccal notch must be provided in the denture which is wider than the labial notch (to accommodate the anteroposterior movement of the buccal frenum under the effect of neighboring muscles as buccinator and Orbicularis Oris muscle). Inadequate buccal notch can lead to dislodgement of the denture when the patient smiles. 4- Buccal vestibule ▪ Extends from buccal frenum anteriorly to the hamular notch posteriorly on each side. ▪ It is occupied by the buccal flange of the denture. Buccal vestibule Buccal flange 4- Buccal vestibule: The buccal vestibule is bounded: ▪ Laterally: Buccinator muscle and Coronoid process of the mandible. ▪ Superiorly: Zygomatic process of the maxilla. ▪ Medially: Residual alveolar ridge. The thickness of the buccal flange of the denture must not be thick to avoid dislodgement by the coronoid process of the mandible Coronoid process of the mandible 5- Hamular notch (Pterygomaxillary notch): It is a narrow cleft (depression) of loose connective tissue between the distal surface of tuberosity and the hamular process of the medial pterygoid plate. The width is approximately (2 mm) antero-posteriorly. It is used as a landmark for the correct extension of the posterior border of the maxillary denture. Significance: Slight displacement (pressure) of the hamular notches provides posterior palatal seal of the maxillary denture. Overextension of the denture base beyond the pterygo- maxillary notch may cause soreness. Under-extension may cause poor retention. 6- Vibrating line: Is an imaginary line drawn across the posterior part of the palate that extends from one hamular notch on one side to the other hamular notch. the It is located at the junction of movable and immovable tissues of the soft palate. Vibrating line 6- Vibrating line cont. It is actually described as an area rather than a line which is butterfly shaped and known as Posterior Palatal Seal Area. The vibrating line determines the Posterior limit of the maxillary denture. It is important for retention of the maxillary denture 1446 II- Maxillary Denture Foundation Dr. Rania M. Moussa 1- Residual Alveolar Ridge: It is the portion of the alveolar process and its soft tissue covering, which remains after teeth extraction. It is Covered by keratinized mucosa and dense fibrous connective tissue firmly attached to the underlying bone The highest continuous surface of the ridge is called Crest of the Ridge. Sides of the ridge are known as lateral slopes. Labial Crest of slopes the ridge Buccal slopes 1- Residual Alveolar Ridge: Labial slopes Crest of the ridge Buccal slopes Clinical significance: Crest of the residual alveolar ridge ……………..Primary stress bearing area Labial and buccal slopes of the residual ridge ……….. Secondary stress bearing areas 2- Maxillary Tuberosity: This is the most distal part of the residual alveolar ridge and presents a hard tissue landmark. It is a rounded bulge behind and slightly above the distal end of the residual ridge. Clinical Significance: 1- Denture base should cover the tuberosity: WHY? a. Its walls resist horizontal forces. b. It permits wide area coverage thus enhance retention and better load distribution. 2- The last posterior tooth should not be placed on the tuberosity. 3- Extremely large tuberosities may need surgical correction before denture construction 3- Palatine vault (palate): Formed anteriorly by the hard palate and posteriorly by the soft palate. Palatal vault has different forms according to the development of the maxillary process. The shape of the palatal vault affects support and lateral stability. U-shaped palatal vault is the most desirable for stability U-shaped V-shaped Flat 3- Palatine vault (palate): Clinical significance: Central flat part…………….Primary stress bearing area Lateral slopes……………….Secondary stress bearing areas Lateral slopes Central flat palatal part 5- Rugae: These are irregular shaped ridges of dense connective tissue Radiating from the median suture in the anterior 1/3rd of the palate. Clinical Significance: 1. Rugae area is a Secondary stress bearing area 2. It affects phonetics especially the letter “S” 3. It increases the surface area thus supplements retention. 4. It enhances stability.  4- Fovea palatini: ▪ Are two small pits or depressions one on each side of the midline. They are openings of ducts minor salivary glands. ▪ Located slightly posterior to the junction of the hard and soft palate. Clinical Significance: It is used as a landmark in locating the posterior border of the maxillary denture. The posterior border of the maxillary denture extends about 2 mm posterior to the fovea palatini 1446 III- Maxillary Relief areas Dr. Rania M. Moussa 1- Incisive papilla: Is a pad of fibrous connective tissue covering the orifice of the incisive foramen at the end of nasopalatine canal (exist of nasopalatine nerves and vessels). It is located at midline, palatal to the necks of the central incisors When severe resorption of alveolar ridge occurs, it is located on the crest of the ridge. Incisive papilla should be relieved because: Pressure on the incisive papilla may cause paresthesia or burning sensation.  2 Clinical Significance: 1 Incisive papilla helps in complete denture construction: 1- It is a biometric guide for proper placement of of maxillary canines (a horizontal line drawn through the center of the incisive papilla passes through the canines). 2- It is a biometric guide for proper placement of the artificial central incisors, that should be placed are about 8-10 mm anterior to the incisive papilla, irrespective of bone resorption. 2- Mid palatine raphe ▪ Elevated bony area located at the midline of the hard palate. ▪ It is covered by thin layer of mucosa. ▪ It covers the median palatine suture. ▪ It is relieved to prevent rocking and consequently denture midline fracture. Mid palatine raphe 3- Torus Palatinus: It is a hyperplastic overgrowth of bone at the mid line of the palate covered by thin mucous membrane. When small, may be relieved in the denture. Should be surgically removed if: 1. Too Large 2. Lobulated 3. Extending to the posterior palatal seal area. 4- Sharp bony spicules or prominences: Recent extraction bony Canine eminence Zygomatic process sockets (Malar bone)  5- Hyperplastic (enlarged) Maxillary Tuberosity: It may interfere with denture placement and removal May cause pain to the patient. Large tuberosities, require surgical treatment. 1446 Questions Dr. Rania M. Moussa References: 1- Hassaballah M AM, Talic YF. arrangement of teeth, in; Principles of complete denture prosthodontics. King saud University, Academic publishing and press, Riyadh, Saudi Arabia, 2004. Chapter 2: Anatomical consideration of denture bearing area. Page 13-20 2- Rahn, A. O., Ivanhoe, J. R., Plummer, K. D., & Heartwell, C. M. (2009). Textbook of complete dentures. Shelton, Conn: People's Medical Publishing House. Chapter 2:Anatomical Landmarks of Significance in Complete Denture Treatment. Page 5-13. 3- Binu George : Textbook of Complete Denture Prosthodontics, 2019. 1446 Thank www.themegallery.com You Company Logo Dr. Rania M. Moussa