OBI 814 - RD5 - Exam2

• RD-5 covers dentition along with neonatal and childhood oral function development.
• Listed learning objectives include neonatal adaptations, neonatal reflexes, oral microbiota, oral anomalies, maturation of oral functions, causes/treatments of malocclusion, and speech acquisition timeline.

Neonatal Adaptations for Survival in Extrauterine Life

• A baby adapts to breathe and take in oxygen by adapting their lungs for gas exchange as there is no longer oxygen delivery coming from the placenta.
• Gas exchange requires the clearance of fetal lung fluid, surfactant secretion, and pulmonary vasodilation.
• External and internal stimuli initiate the first breath

Changes at the Heart-Lung Interface for Circulatory Transition

• At birth, the lungs expand and clear fluid from the alveoli, while the ductus arteriosus closes.
• Pressure increases in the heart's left atrium and decreases in the right, causing the foramen ovale to close.
• The ductus arteriosus connects the pulmonary artery to the aortic arch, diverting deoxygenated blood but becomes the ligamentum arteriosum after closure.
• Oxygenated blood entering the right atrium is diverted to the left atrium; and after birth the increased left atrial pressure causes the closure, which turns into the fossa ovalis
• Oxygenated blood returns from the placenta through the umbilical vein shunting from the liver into the inferior vena cava and becoming the ligamentum venosum when it closes at birth.

Metabolic Adaptation

• After the umbilical cord is clamped, neonate receives necessary nutrients from breast milk.
• Prolactin is required for milk production, while oxytocin is needed for milk ejection through positive feedback.
• Newborns require colostrum (initial milk), which is rich in proteins, vitamin A, salts, carbohydrates, lipids and antibodies
• Full breastfeeding correlates with oral health, relating inversely to caries prevalence along with decayed and filled teeth.

Newborn Reflexes

• Autonomic and involuntary, controlled by the brain stem

Persistent Reflexes

• Breathing, blinking, pupillary, sneeze, cough, gag, and swallowing

Breathing Reflex

• Infant anatomy has differences in size, composition, position, and shape making them prone to obstruction.
• Neonates are nose breathers, aided by short larynx moving forward and protecting lower airways from obstruction.

Swallowing Reflex

• Tongue and pharyngeal muscles push bolus to the back of the mouth using 25 muscles, 5 cranial nerves, and the brainstem.
• There are 3 phases: oral, pharyngeal, and esophageal
• Oral can be voluntary or involuntary

Neonatal/Primitive Reflexes

• Present at birth, dissipating around 4-6 months
• Brain maturation allows for voluntary motor activities
• Examples include the Moro (startle) reflex, tonic neck reflex, grasp reflex, Babinski reflex, step reflex, swim reflex, and crawl reflex.

Oro-Pharyngeal Reflexes

• The extrusion reflex prevents choking on solids.
• As solids enter the mouth, the tongue extends, and lips close.
• This reflex is important because newborns are small and muscles are underdeveloped
• It disappears around 4 months old. Solid foods should not be given until after
• Persistence beyond that point causes tongue thrust, pushing the tongue against the teeth when swallowing, causing speech/dental issues.

Rooting, Suckling, and Swallowing Reflexes

• Sucking develops around week 10 in utero and swallowing develops in week 12.
• Infants are born with reflexes which allow them to complete the feeding cycle.
• Stroking or touching a baby's mouth corner makes them turn their head and open thier mouth.
• Baby sucks when the palate is touched
• The babys swallows when his mouth is filled with milk or liquid
• Infantile swallowing dissipates as a mature swallowing reflex persists throughout life

Swallowing and Breathing Reflexes

• They are coordinated
• The infant breathes through the nose with a relaxed soft palate and an open airway
• During swallowing, the soft palate stretches to close off the nose.

Sucking/Feeding Behavior

• The suckling system may not be ready for preterm infants
• Functional at term

Neonatal Oral Anomalies

• Oral cysts are present in newborns at a rate of 65-85%. No intervention needed.
• Epstein pearls are benign whitish-yellow cysts on the roof of the mouth.
• Palatal cysts are in the midline of the palatine bone and result disappear within 1-2 weeks after birth.
• Bohn's nodules are benign smooth white cysts filled with keratin, in the gingival region on the buccal or lingual surface of the alveolar ridge (not the crest), or hard palate, away from midline.
• Dental lamina cysts (Gingival cysts) are benign, transient oral mucosal lesions of the gum.
• They are small, isolated/multiple whitish gingival cysts, found on the alveolar ridge, and disappear after after birth Natal teeth are uncommon and removed shortly after birth

Natal Teeth

• Natal teeth are uncommon, present at birth
• Intervention is needed, and removal needs to be done shortly after birth
• Teeth have little root structure, and often develop in the lower gums, being considered wobbly
• May irritate infant's tongue, or mothers nipple during nursing
• The teeth will cause a risk of breathing issues
• Ellis-van Creveld syndrome, Hallermann-Streiff syndrome, cleft palate, Pierre-Robin syndrome/sequence, and Sotos syndrome are all causes

Tongue-Tie (Ankyloglossia)

• Tongue tie is common at birth
• Caused by a shortened or thick lingual frenulum that can restrict tongue movement.
• Causes issues with breastfeeding or speech.
• A Frenotomy with sterile scissors corrects this.

Acquisition of Oral Microbiota

• Newborns are inhabited with microbes as they pass through their mothers birth canal
• Early colonizers: Streptococcus sp., Staphylococcus sp., Fusobacterium sp., Veillonella sp., Lactobacillus sp., Candidia sp.
• Later colonizers: Gemella sp., Granulicatella sp., Haemophilus sp., Rothia sp.
• There are 3-6 months until the appearance of milk teeth
• Primary Dentition presents with Streptococcus mutans, Fusobacterium sp., Tenericutes sp.
• This allows for development/growth of specific microorganisms living in the body

Maturation of Oral Functions Without Dentition

• Taste buds are present at birth
• Can discriminate tastes
• Neural connection is immature
• Infant have acute taste
• Fetal taste buds activate during 30th week of gestation
• Pediatric dentists promote health food lifestyle during gestation because that influences preferences

Development of Salivary Function

• Salivary grands develop from signals mediated interactions, 6-8 weeks into fetal age
• At birth the salivary glands produce small amounts of saliva
• at 3 months the saliva function increases, especially before teething
• Babies drool until the muscles develop around 2 years of age
• teething can simulate drooling

Growth of Mandible During the First Few Years

• Formed by intramembranous ossification off 1st, around 6 weeks in utero
• Growing downwards and forwards
• mediated by endochondral ossification for condylar cartilage
• Infants have small mandibles and short ramuses that continues to grow with primary teeth appear
• The mandible grows the most vertically first year

Pediatric Maturation of Swallowing-Breathing

• Postnatal, structures in the mouth and pharynx change
• Infants have full tongues and high hyoid bones causing diminished elevation of larynx
• Toddlers have adult like features, but less lecation elevation
• Older children grow in their intraoral space from mandibles growing downward causing the larnyx and hyoids to enlarge

Acquisition of Speech

• Breathing happens through nose, with soft palate relaxed
• With speech, soft palate stretches to cover mouth
• Sound production happens through vibration of cords, up trache and voice box
• Shaped into words by controlling soft palate, tongue and lips.
  • Without Teeth
  • 2-3 years (p b m w), closure of lips
  • 2-4 (q we), lips mouth and air
  • 2.5-4 (k g), quick air

Tooth Eruption Requires PTHrP Activity

• PTHrP from dental follicle cells bind to receptors in osteoblasts, which makes RANKL and activates bone resorption during teething

Dentition of Deciduous Primary Teeth

• Initiation of mastication begins when teeth erupt
• at 5–6 months (weaning) anterior teeth begin to erupt
• around 2 year old molar erupts
• 3, occlusion of teeth in completed

Dentition of Permanent *Secondary Teeth

• Listed is date for eruption, exfoliation

Dental Anomalies (Abnormal Dentition)

• May result in abnormal size, shape, position and crowding
• May cause: Early Loss, repetitive oral habits, genetics
• Tooth decay, chewing and psychological harm.

Genetic Oral Malocclusion

• Tongue thrust

Gene-Related Malocclusion

• Marfan, Pierre Robin, Treacher Collins
• May result in speech disorder from small jaws or cleft palate
• Often from craniofacial deformity

Non-Nutritive Sucking Oral Habits

• Sucking habits adopted by babies
• Comfort for sucking urges
• Dentofacial structure dependents on pacifiers

Duration Sucking

• AAPD says to stop bad chewing at 3
• Duration effects malocclusion.
• Prolonged pacifier or thumb can over extend front or cross bite

Malnutrition

• Cause or oral malocclusion, causing loss of teeth or decay

Interventions for Malocclusion

• Digital, corrected by weaning and explaining