This lecture is sponsored by a grant from the Delta Dental of Iowa Foundation IDA Annual Conference Guest Lecture Series.

Radiology: Back to the Classroom! Juan F. Yepes DDS, MD, MPH, MS, DrPH Associate Professor of Pediatric Dentistry Indiana University School of Dentistry James Whitcomb Hospital for Children jfyepes@iupui.edu Member of the Executive Committee of the American Academy of Oral and Maxillofacial Radiology (2008-2012)

Radiation Safety

Population case-control study: almost 2,800 subjects, aged 20 to 79. Introduction Subjects were asked to recall their frequencies of dental radiographic examinations during four age-periods; younger than 10 years of age, between 10 and 19, 20 and 49, and older than 50. The researchers reported an increased risk of meningioma in individuals who received bitewing radiographs on one or more occasions per year in all age groups. (OR=2) Subjects who received a panoramic film were reported to be an increased risk for meningioma (OR=4.9) if were exposed under 10 years of age. No increased risk of meningioma was noted for subjects who received panoramic film over the age of 10 or a full mouth series of intra-oral radiographs at any age.

Introduction Some issues to consider Recall bias!! asking a subject to recall an event 50 years ago or more. Bitewing radiographs (2-4) were reported to place patients at a higher risk for meningioma than a full mouth series (up to 20 exposures). Different radiographic equipment with intrinsic variations in the exposure times. Impossible to calculate dose-response.

Radiation.Who cares? Antepartum dental radiography and Infant low birth weight Potential mothers Chronic exposure to radiation (stochastic) Develop subclinical hypothyroidism Got pregnant Delivery babies with LBW Images downloaded from Microsoft Office Clip Art

Radiation Biology and Protection

Let s review the basic concepts in radiation biology Radiation biology Radiation Protection Dosimetry

Radiation Biology It is the study of the effects of ionizing radiation on living systems. Ionizing radiation Tissues Modification of biological molecules Alterations in cells (time?) Injury or death.

Radiation Biology x ray An electromagnetic radiation of great penetrating power, produced by the bombardment of a substance (usually a heavy metal) by a stream of high velocity electrons, usually in a vacuum tube. The wavelength is usually less than 2 Å.

Radiation Biology

Radiation Biology Radiosensitivity and Cell Type Bergonie and Tribondeau 1906 Most radiosensitive cells 1. Cells with a high mitotic rate 2.Those cells who undergo many future mitosis 3. Cells with very primitive differentiation

Radiation Biology Deterministic effects The response is proportional with the magnitude of the dose Biologic effects of x-rays Example: effects of radiation therapy in the mouth Stochastic effect The response is proportional with the frequency of the dose

Radiation Biology Cancer Type Estimated New Cases Estimated Deaths Bladder 74,690 15,580 Breast (Female Male) 232,670 2,360 40,000 430 Colon and Rectal (Combined) 136,830 50,310 Endometrial 52,630 8,590 Kidney (Renal Cell and Renal Pelvis) Cancer 63,920 13,860 Leukemia (All Types) 52,380 24,090 Lung (Including Bronchus) 224,210 159,260 Melanoma 76,100 9,710 Non-Hodgkin Lymphoma 70,800 18,990 Pancreatic 46,420 39,590 Prostate 233,000 29,480 Thyroid 62,980 1,890 American Cancer Society: Cancer Facts and Figures 2014. Atlanta, Ga: American Cancer Society, 2014.

Radiation Biology Using statistical models for analysis, rates for new thyroid cancer cases have been rising on average 4.5% each year over the last 10 years. Using statistical models for analysis, rates for new female breast cancer cases have been stable over the last 10 years. Death rates have been falling on average 1.9% each year over 2004-2013

Let s review the basic concepts in radiation protection and dosimetry Radiation biology Radiation Protection Dosimetry

Radiation Safety and Protection Dosimetry Equivalent dose (Ht): it is used to compare the biological effects of different types of radiation to a tissue or organ. It is the sum of the products of the absorbed dose (Dt) averaged over a tissue or organ and the radiation weighting factor (Wr) depends on the specific tissue Ht = Σ Wr x Dt IS Unit Sievert (Sv) Traditional unit rem 1 Sv = 100 rem

Radiation Safety and Protection Dosimetry IS Unit Sievert (Sv) Traditional unit rem 1 Sv = 100 rem

Radiation Safety and Protection Sources of Radiation Exposure Natural Radiation Cosmic Sources Subatomic particles and photons from the sun. It is primarily a function of altitude Orlando (82 ft.): 0.24 msv / Year Denver (5,280 ft.): 0.50 msv/year Indianapolis (715 ft.): 0.28 msv/year Exposure resulting from airline travel 5 hours flight: 0.025 msv

Radiation Safety and Protection Natural Radiation Terrestrial Sources External Radiation: Radioactive nuclides in the soil, primarily potassium 40 and the radioactive decay products of uranium 238, and thorium 232 (0.5 msv / year) Radon: Radon is a decay product in the uranium series. It is responsible of 52% of the radiation exposure of the world s population (1.2 msv/year). It is a GAS attached to dust particles LUNGS Other Internal: Ingestion of uranium

Radiation Safety and Protection Man-Made Radiation Medical Diagnosis and Treatment Well over one billion medical x-ray examinations are performed annually worldwide. Consumer and Industrial Products Domestic water supply, tobacco products, combustible fuels, dental porcelain, television receivers, pocket watches, smoke alarms, and airport inspection systems.

Radiation Safety and Protection Cosmic Natural 83% (3mSv / year) Terrestrial Sources of Radiation Exposure 3.6 msv / year Internal radon Ingestion of food Artificial 17% (0.6mSv / year) 2.4 msv http://www.ans.org/pi/resources/dosechart/msv.php

Radiation Safety and Protection Risk Estimates The primary risk from dental radiography is radiation-induced cancer (stochastic ) The risk for cancer being induced in human as a result of exposure to low doses of radiation is difficult to estimate for different reasons: - The data for the cancer risk from radiation exposure involve exposures many times larger than dental radiology - Cancer is a common disease. It is difficult to detected the effect of dental radiography - The time between the radiation exposure and the development of cancer may be years to decades.

Radiation Safety and Protection Key Principles of Radiological Protection The Principle of Justification: Any decision that alters the radiation exposure situation should do more good than harm. The Principle of Optimization of Protection: The likelihood of incurring exposure, the number of people exposed, and the magnitude of their individual doses should all be kept as low as reasonably achievable, taking into account economic and societal factors. The Principle of Application of Dose Limits: The total dose to any individual from regulated sources in planned exposure situations other than medical exposure of patients should not exceed the appropriate limits specified by the Commission.

Effective Dose from Diagnostic Radiology and equivalent background Examination Intraoral Posterior BW (F-speed) (rectangular collimation) FMX (rectangular c.) FMX (round collimation) Panoramic Cephalometric Extraoral CBCT I-CAT (extended view: 16 x 13 cm) 10 y.o. CBCT Accuitomo 170 (small view: <40 cm²) 10 y.o. CBCT Kodak 9000 3D (small view: <40cm²) 10 y.o. CBCT I-CAT Next generation (medium view) 10. y.o Effective Dose (msv) 0.005 0.6 0.035 0.171 0.006-0.026 0.002-0.066 4 21 0.134 13 Equivalent background radiation (days) 1-3 0.5-1 0.028 2.8 0.016 1.6 0.063 6.3 CT Head 2 243 Background radiation: 3.6 msv / year

NCRP Report 145 Radiation Protection in Dentistry December, 2003 Pg. 21: Rectangular collimation of the x-ray beam shall be routinely used for periapical radiography

Collimation Collimation limits the amount of radiation, primary and scattered, to which the patient is exposed Rectangular collimator decreases the radiation dose by up to fivefold as compared with a circular one. (1) Use of long source-to skin distances of 40 cm, rather than short distance of 20 cm.(2) (1) Gibbs SJ. Effective dose equivalence and effective dose. OOOO 2000; 90(4): 538-545 (2) National Council of Radiation Protection 2003

Intraoral Radiographic Imaging: A Study Comparing Collimation and Thyroid Shielding Methods on a Pediatric Phantom Patient Zachary D. Bozic 1 Juan F Yepes, DDS, MD, MPH, MS, DrPH Indiana University School of Dentistry, Indianapolis Indiana Units: (μsv) Rectangl e w/tc Round w/ TC Bone Marrow 0.0 0.4 thyroid 0.3 1.2 esophagus 0.0 0.1 skin 0.0 0.0 bone surface 0.2 2.1 Salivary glands 6.0 40.0 lens of eyes 1.6 1.0 Pituitary 1.2 3.7 Effective Dose 0.2 1.3

Radiation Safety and Protection Leaded aprons and thyroid shields that contain lead or other materials are patient protective equipment. If all the NCRP recommendations are followed rigorously, the use of lead apron on patients is not required. (1) Thyroid shielding with a leaded thyroid shield or collar is strongly recommended for children and pregnant women. (2) Thyroid collars are also recommended for adults when it will not interfere with the exposure. (1) To prevent cracks in the leaded shield, practitioners should enforce that leaded aprons and collars are hung and not folded (1) National Council for Radiation Protection & Measurements; 2003 (2) US Department of Health and Human Services, Public Health Service, FDA and American Dental Association Council of Scientific Affairs, 2004

We learned about radiation biology, radiation protection, dosimetry.now, let s review how often and when we prescribe radiographs.

Radiation Safety and Protection Patient Selection Criteria Little evidence to support radiographic exposure of all edentulous areas of the oral cavity. Clinical evaluation + Combined selected periapical radiographs can result in a 43% reduction in the number of films without a clinical consequential increase in the rate of undiagnosed disease. ADA and FDA developed guidelines for the selection of patients for dental radiographic examination. Revised 2012

Radiation Safety and Protection Patient Selection Criteria Radiographs must be limited to the areas required for adequate diagnosis and treatment based on professional judgment Dentist should not prescribe routine radiographs at preset intervals for all patients For new or referred patients, clinicians should obtain recent dental radiographs from the patient s previous dental health care provider Dental radiographs my be prescribed for pregnant patients with careful adherence to the radiation safety protocols Dentist should prescribe dental radiographs ONLY after clinical evaluation Revised 2012

Dosimetry of two direct digital imaging devices using a pediatric phantom J.R. Schulten 1, J.F. Yepes 1, J. Ludlow 2, A. Page 1 1 Department of Dentistry, Division of Pediatric Dentistry, University of Kentucky, Lexington, KY 2 Oral and Maxillofacial Radiology, University of North Carolina, Chapel Hill, NC West to East Flight: 25µSv Equivalent doses in µsv PBW avg Pan avg Bone Marrow 3 3 thyroid 37 79 esophagus 1 2 skin 8 16 bone surface 14 14 Salivary glands 193 183 brain* 4 6 remainder average 25 28 lymphatic nodes* 6 7 extrathoracic airway* 123 141 muscle* 6 7 oral mucosa* 192 205 lens of eyes 11 6 Pituitary 8 9

Radiation Safety and Protection Digital Imaging DOSE REDUCTION Practitioners and manufacturers frequently use the reduction of the radiation dose that the patient receives as a reason to implement digital radiography. There are several reasons why the dose reduction is not as large as often suggested: The dose reduction compared with F-speed film is somewhere between 0 to 50% (** phosphorous plate carry the risk of higher exposure than conventional films) Increase in the number of radiographs made: Several studies indicate that the decision to make a radiograph is reached more easily with a digital system Increase in the number and ease or remakes

ALARA Principle Only perform imaging when there is a clear medical or dental benefit to the child. Use the lowest amount of radiation for adequate imaging based on the size of the child. Only take images on the indicated area and always using the thyroid collar Avoid multiple unnecessary images (Role of digital Imaging). Use alternative diagnostic studies, if possible.

Principles of Radiographic Interpretation

Principles of Radiographic Interpretation Condensing osteitis There is a radiopacity, not too big, not too small, looks actually funny..located at the apex of tooth # 28.

Principles of Radiographic Interpretation Radiographic Description Differential Interpretation

Some Definitions

Well localized Well defined The item being reported is limited to a specific area, and does not extend beyond that locality. The edges of the item being reported are reasonably sharp and clearly define the extent of the lesion.

Poorly localized Poorly defined The item being reported is not limited to a specific area, and extends into surrounding anatomical sites. The edges of the item being reported are not sharp. The actual borders and thus the exact extent of the lesion are not clearly defined.

Corticated The entity being reported is not only well defined, but has a cortex, i.e. an osseous border, seen as a thin white line.

Multilocular The entity being reported is usually well defined and has a cortex, i.e. an osseous border, seen as a thin white line, but is partially or totally subdivided into several loculi.

Summary of Interpretation Steps 1. Radiopaque / Radiolucent / mix 2. Well defined / ill defined / mix 3. Corticated / non-corticated / mix 4. Location, size and shape 5. What happen in the neighborhood 6. Differential interpretation

Time for practice

Most Common Jaw Lesions

Bone Disorders

Bone Disorders 1. Idiopathic Bone Sclerosis 2. Fibrous Dysplasia 3. Ossifying Fibroma 4. Simple Bone Cyst 5. Cemento-osseous dysplasia

Idiopathic Bone Sclerosis (not condensing osteitis!)

Idiopathic Bone Sclerosis IBS is a focal solitary sclerotic lesion that arises in the late 1st or early 2nd decade of life. Its cause is unknown. It is asymptomatic, is not associated with inflammation, and may remain static or demonstrate slow growth that usually stops when the patient reaches skeletal maturity.

Idiopathic Bone Sclerosis In 90% of patients it occurs in the mandible, usually near the first molar or second molar or premolar. At imaging, IBS is radiopaque, well defined, well localized, non-corticated, located at the apex of vital teeth. No root resorption and no teeth displacement. Some patients may have multiple lesions.

Simple Bone Cyst

-Traumatic bone cyst, hemorrhagic bone cyst, solitary bone cyst -Simple bone cyst: It is a cavity within bone that is lined with connective tissue. It may be empty or it may contain fluid -It is not a true cyst -Etiology unknown, however Localized aberration in normal bone remodeling or metabolism -First two decades of life (mean 17 years) -Females 2:1 -Expansion is possible but unusual, discovery by chance Simple Bone Cyst

Mandible Posterior mandible Associated with cemento-osseous dysplasia and fibrous dysplasia Margin: Well defined to ill-defined border Internal structure: Radiolucent, it may appear multilocular, although the lesion does not contain true septa No effect on the surrounding teeth Lamina dura intact and vitality positive

Fibrous Dysplasia

Localized change in normal bone metabolism Replacement of all components of normal bone by fibrous tissue containing varying amounts of abnormal appearing bone Solitary or multiple (monostotic 70% of all cases) McCune-Albright syndrome Asymptomatic, rare associated with pain The lesion may become active Pregnant, etc.. The skull is involved in 10 to 25% of cases Patients between 10 and 30 years old

Focal Cemento-Osseous Dysplasia

Focal cemento-osseous dysplasia -Localized change in normal bone metabolism Replacement of the components of normal bone with fibrous tissue and cementum-like material, abnormal bone or a mixture of the two -Near the apex of a tooth -Middle age, females 9:1, Afro-American -Incidental finding -The involved teeth are vital -Sometimes quite larger Source: Oral Radiology, Principles and Interpretation. White et al,2000

Focal cemento-osseous dysplasia -Epicenter usually at the apex of a tooth -Well defined, Irregularly shaped -Internal structure: Varies Radiolucent area Mixed stage: Radiopaque and Radiolucent areas Mature stage: Radiopaque -Lamina dura of the teeth involved with the lesion is lost -Rare: resorption of the roots

Odontogenic Cysts

Radiographic Features: Location Cyst may occur centrally in any location in the maxilla or mandible Cyst are rare in the condyle and the coronoid process A few cyst arise in the soft tissues of the orofacial region Cyst Periphery Radiolucent Well defined and corticated However a secondary infection can change this

Radiographic Features: Shape Cyst are usually round or oval, resembling a fluid filled balloon Some cyst may have a scalloped borders Internal Structure Cyst Cyst are often totally radiolucent Long standing cyst may have some calcifications inside Some cyst have septa

Cyst Radiographic Features: Effects on Surrounding Structures Cyst grow slowly Sometimes displacement and resorption of the teeth Cyst can expand the mandible

Odontogenic Cyst Radicular Cyst Residual Cyst Dentigerous Cyst Buccal bifurcation cyst Keratocystic Odontogenic Tumor Basal cell nevus syndrome Lateral Periodontal Cyst Calcifying odontogenic Cyst Non-Odontogenic Cyst Naso-palatine canal cyst Images downloaded from Microsoft Galleries

Radicular Cyst

Radicular Cyst Periapical cyst, Dental cyst Radicular cyst is a cyst most likely originated when rest of epithelial cells (Malassez) in the periodontal ligament are stimulated to proliferate and undergo cyst degeneration by inflammatory products from a non-vital tooth. Most common cyst in the jaws They arise from non-vital teeth Asymptomatic, unless secondary infection occurs

Radicular Cyst Periapical cyst, Dental cyst In most cases the epicenter of the RC is located at the apex 60% are found in the maxilla, especially around incisors and canines Well defined cortical border, if secondary infected, the inflammatory reaction may result in loss of the cortical bone Internal structure Radiolucent

Buccal Bifurcation Cyst

Buccal Bifurcation Cyst Buccal bifurcation cyst (BBC) is an inflammatory odontogenic cyst that usually occurs at the buccal region of the first or second primary mandibular molars. Several names are used to describe this condition including the term juvenile paradental cyst. According to the World Health Organization the BBC is listed under the category of paradental cyst and named mandibular infected buccal cyst. BBC occurs in children between 5 and 13 years of age. Usually affects the second primary molar. Delayed tooth eruption and swelling at the affected area is commonly observed. In some cases, partial tooth eruption with crown buccal tilting and deep periodontal pockets is observed. Radiographically, the BBC is characterized by a well-defined radiolucent area, often corticated around the roots of the involved teeth. Usually the lamina dura is not affected. Surgical excision of the lesion is the treatment of choice.

Dentigerous Cyst

Dentigerous Cyst A dentigerous cyst is a cyst that forms around the crown of an unerupted tooth. It begins from accumulation in the layers of reduced enamel epithelium or between the epithelium and the crown of the unerupted tooth. Second most common cyst in the jaws They develop around the crown of an unerupted or supernumerary tooth

Dentigerous Cyst Radiology Features The epicenter is just above the crown of the involved tooth The cyst is attaches at the CEJ Very often are quite big before diagnosis Well defined cortex Completely radiolucent

Dentigerous Cyst Radiology Features -DG often displace and resorb adjacent teeth -Displaces the associated tooth in a apical direction Differential Diagnosis - Hyperplastic follicle - KOT: Less likely resorb teeth Attach more apical - Cystic ameloblastoma

Keratocystic Odontogenic Tumor (former OKC)

Keratocystic Odontogenic Tumor Non-inflammatory odontogenic cyst that arises from the dental lamina. Unlike other cyst, the epithelium of the OKC appears to have innate growth potential. The epithelium lining is keratinized and thin. Inside the cyst viscous white material cheese

Keratocystic Odontogenic Tumor -OKCs account for above 1/10 of all cyst in the jaws -Second and third decades with slightly male predilection -No symptoms until mid size swelling -High recurrence -Aspiration Keratin

Keratocystic Odontogenic Tumor Radiographic The Features: Radiology of Oral and Perioral Cysts -90% Posterior body of the mandible -Epicenter superior to the inferior alveolar canal -Looks very similar to dentigerous cyst -Well corticated and radiolucent -MINIMAL EXPANSION -Resorb teeth bust less than DC

Non-Odontogenic Cysts

Naso-palatine Canal Cyst -Remnants of the naso-palatine duct -10% of jaw cyst -Most cases between 15-20 years old -Asymptomatic or mild symptoms

Naso-palatine Canal Cyst RADIOGRAPHIC FEATURES: -Well defined, corticated and is circular or oval in shape. The shadow of the ANS sometimes is superimposed heart shape -Internal structure: complete radiolucent -Most common this cyst causes the roots of the central incisors to diverge and occasionally root resorption occurs.

Inflammatory Lesions

Osteomyelitis

Osteomyelitis Osteomyelitis affects children with a strong male predilection Typical signs and symptoms (acute): rapid onset pain, swelling, fever, and lymphadenopathy. The associated teeth may be mobile and sensitive to percussion. Paresthesia is NOT uncommon Very early in the disease no radiographic changes

Osteomyelitis The most common location is the posterior body of the mandible (rare in the maxilla) Ill-defined periphery with gradual transition to normal bone trabeculae. Initially decrease in the density of the bone Later regions of sclerotic bone : sequestra Acute osteomyelitis can stimulate either bone resorption or bone formation Differential diagnosis in children: fibrous dysplasia

Benign Tumors

Benign Tumors 1. Ameloblastoma 2. Calcifying epithelial odontogenic tumor (Pindborg tumor) 3. Odontoma 4. Ameloblastic Fibroma 5. Adenoid Odontogenic Tumor (AOT) 6. Myxoma 7. Benign Cementoblastoma 8. Osteoma 9. Hemangioma

Adenomatoid Odontogenic Tumor (AOT)

Adenomatoid Odontogenic Tumor Most frequently found in child or adolescent. Frequently but not invariably envelopes crown of unerupted tooth especially maxillary canine. Most frequently unilocular but can be loculated. Well defined margin. Homogeneous radiolucent area initially but later develops calcified floccules as content. Cortical expansion may occur. Tends to displace rather than cause resorption of adjacent teeth.

Adenomatoid Odontogenic Tumor (AOT) 10-20 (14 years of age) Anterior maxilla or mandible Radiolucent with radiopaque foci May mimic dentigerous cyst In the canine area most frequent location

Ameloblastic Fibroma

Ameloblastic fibroma Most frequently found in children and adolescents. Quite uncommon. Can be unilocular, crenulated or multilocular. Outline well-delineated and corticated. Homogeneous radiolucency. Cortical expansion a late finding. May cause displacement of teeth. Less aggressive locally than non-unicystic ameloblastomas.

Odontoma

Compound Odontoma

Compound Odontoma A malformation in which all the dental tissues are represented in a more orderly pattern than in the complex odontoma, so that the lesion consists of many toothlike structures.

Compound Odontoma Most of these structures do not represent, morphologically, the teeth of the normal dentition, but in each one, enamel, dentin, cementum and pulp are arranged as in a normal tooth.

Benign Cementoblastoma

Benign Cementoblastoma Second or third decade, usually before 18 Slow growing mesenchymal neoplasms Composed principally of cementum-like tissue and attached to the apex of a tooth root. More common in males than females. Continuous with root, which is resorbed Pulp vitality unrelated but the involved tooth is OFTEN painful

Benign Cementoblastoma Cementoblastomas occur more often in the mandible (premolar or first molar) The lesion is well defined and radiopaque with cortical border and then a well defined radiolucent band inside the cortical border. Differential diagnosis FCOD

Ossifying Fibroma

Juvenile Ossifying Fibroma

Juvenile Ossifying Fibroma (trabecular pattern) Radiographic Features: The lesion is often well defined and unilocular. The borders are well defined. Tumor-like behavior growth of the lesion, displacement of teeth and the inferior alveolar canal. Usually the cortical borders remain intact Depending on the amount of calcified material produced in the tumor, it may appears completely radiolucent; more often, different degrees of radiopaques areas are noted inside.

Malignant Tumors

Again 1. Radiolucent / radiopaque 2. Well defined or poor defined 3. Corticated or non corticated 4. What happen around: resorption? 5. Differential Interpretation

Malignant Tumors 1. Sarcoma 2.Chondrosarcoma 3. Ewing s Sarcoma 4.Multiple Myeloma 5. Acute Lymphocytic Leukemia

Ewing s Sarcoma

Ewing s Sarcoma Ewing s sarcoma is a tumor of long bones that is relatively rare in the jaws. Lesions arise in the medullary portion of the bone and spread to the endosteal and later to the periosteal surface. It is most common in the middle of the second decade of life (~ 15 y.o.) Most patients are between the ages of 5 and 30 years old. Males are twice as likely to manifest the disease as females Swelling, pain, loose teeth, paresthesia and trismus are clinical features associated with this tumor.

Ewing s Sarcoma Radiographic Features: - The majority of cases are located in the mandible (posterior area) - Radiolucent, ill-defined and NEVER corticated - Destruction of bone in an UNEVEN fashion - The lesions are usually solitary - Periosteal reactions (sunray appearance) Differential Diagnosis - Osteomyelitis (sequestra)

Acute Lymphocytic Leukemia

Acute Lymphocytic Leukemia Leukemia is a malignant tumor of the hematopoietic stem cells. The most common leukemia in children is ALL. Radiographic features: - Mandible and maxilla in areas of developing teeth - Often around the periapical region of a tooth (periapical lesion) - ill defined radiolucent-radiopaque areas - NO expansion of the bone but displacement of the unerupted teeth - Premature loss of teeth

Thank you so MUCH!!!!!!!!! Juan F. Yepes DDS, MD, MPH, DrPH jfyepes@iupui.edu