Ortho Complications, TMD and References Flashcards
Can you be born with TMJ disk displacement?
Per Paesani et al 1999, NOPE. Studied 30 young infants TMJ’s, all joints had normal superior position. Concluded TMJ disk displacement is not a congenital condition.
What are risk factors for TMD dysfunction?
Trauma Skeletal open bite Excessive overjet 5 or more missing posterior teeth Unilateral lingual crossbite CO/CR discrepancy >4mm
Root resorption is more common with what kind of ortho correction
Correction for open bites, also - root anatomy high force levels extraction therapy amount incisor retraction kids with asthma (?possible)
relapse
2/3 of all patients will experience relapse w/o permanent retention
- lower arch should be maintained during tx
- intercanine width
P Stanier and GE Moore “Genetics of cleft lip and palate: syndromic genes contribute to the incidence of non-syndromic clefts.” Journal of human molecular genetics 2004
- CL/P = one of the most common birth defects worldwide.
- The majority of cases are NON-syndromic.
- They have been unable to find out human genes which reveal the molecular basis for human clefting.
- However, this study identified that many of NON-syndromic CL/P is due to the same genes as syndromic CL/P
T. Ozawa, K. Fujita. “Factors influencing secondary alveolar bone grafting in cleft lip and palate patients: prospective analysis using CT image analyzer,” Journal CL/P 2007
- Objective: to examine the effect of migration of the germ of the lateral incisor into the bone for eruption factors on bone bridge resorption.
- 25 subjects who had secondary alveolar bone grafts
- The volume of the alveolar bone grafts immediately after the operation (V1), bone bridge formation 6 months post operative, and tooth migration into the bridge were measured using CT images.
- In CL/P pts w/a germ of the lateral incisors, it is beneficial to carry out secondary bone grafting to the alveolar cleft at the age of 5 to 7 years, preceding the eruption of the canine, in order to form a good bone bridge that will facilitate eruption of the lateral incisor. `
David S Carlson. Seminars in Orthodontics, 2005. “Theories in Craniofacial Growth in the Postgenomic Era”
- Traces the development of competing concepts and theories of craniofacial development and growth and relates those theories to developments in genetics.
- The overall conclusion: Ortho is entering a new era through the incorporation of principles of developmental-molecular genetics into the tx of developing malocclusions and growth related jaw discrepancies.
ML Moss. “The functional matrix hypothesis revisited: the role of mechanotransduction” (1997)
- Several types of intracellular processes of mechano-transduction are described.
- The mechanical processes translate the informational content of a periosteal functional matrix stimulus into a skeletal unit (bone) cell signal.
- The correlation between the strengths of the endogenous electrical fields produced by muscle-skeletal activity and those to which bone cells maximally respond are stressed.
- A chain of macromolecular levers, connecting the extracellular matrix to the bone cell genome is described, suggesting another means of epigenetic regulation of the bone cell genome, including its phenotypic expression.
- My summary: Muscles act on bones, which creates a cellular signal within the bone itself, these actions regulate each other (bone to muscle).
ML Moss “The functional matrix hypothesis revisited : the role of an osseous connected cellular network,” (1997)
- Intercellular gap jxns permit bone cells to intercellularly transmit and subsequently process, periosteal functional matrix info, after its initial intracellular mechano-transduction.
- Gap jxns underlie the organization of bone tissue as a connected cellular network
- The structural and operational characteristics of such bio networks are outlined and their specific bone cell attributes described. Bone is ‘tuned’ to the frequency of muscle activity.
T Baccetti, L Fanchi Tallaro. “Early dentofacial features of Class II malocclusion: a longitudinal study from the deciduous through the mixed dentition.” Journal of Am Orthodontics dentofacial orthopedics (1997)
- 25 untreated Class II in deciduous dentition (presence of both Class II primary canines, distal step, and excessive overjet) followed with 22 untreated class I in primary (FTP, Class I canines, minimal OB/OJ).
- Occlusal analysis of the Class II group: average interarch transverse discrepancy due to a narrow maxillary arch relative to mandible.
- ALL occlusal class II features were maintained or became exaggerated during the transition to the mixed dentition.
- The skeletal pattern of Class II malocclusion in the deciduous dentition typically characterized by significant mandibular skeletal retrusion and mandibular size deficiency.
- Maxilla grew more, mandible grew less. Condylar axis had a greater downward and backward inclination= an indication of posterior morphogenetic rotation of the mandible.
CONCLUSION: Clinical signs of class II maloccl are evident in deciduous dentiton and persist. Tx to correct Class II problem can be initiated in all three planes of space (RME, headgear, etc).
Hunter WS, Jorgensen. Canada
- OBJ: to test the belief that skeletal age, can be used to predict the timing of the maximum growth of the mandible. To determine the predictive relationship between skeletal age and peak mandibular growth velocity (PMdV) at puberty
- When the actual age of PMdV was determined retrospectively from plots of annual mand growth it was found that only 4/30in the delayed group were delayed and only 2/10 of the accelerated group were actually accelerated.
- Skeletal age is not a reliable predictor of the timing of PMdV.
SE Bishara, FJ Kohout. Changes in the molar relationship between the deciduous and permanent dentitons: a longitudinal study. (1988)
- Obj: to describe the changes in the molar relationship from the deciduous dentition to the permanent dentition in 121 subjs from the Iowa growth study.
- 62% developed into Class I, 34% into class II, and 4% into class III.
- Those sides that started with a distal step in the deciduous dentition proceeded to develop into a class II . Of the sides with a FTP, 56%->Class I, and 44%-> Class II.
- The presence of a mesial step in the primary indicated a greater probability for a class I and a lesser probability of a class II.
Ravn JJ “Longitudinal study of occlusion in the primary dentition in 3 and 7 year old children,”
Most aspects of occlusion were unstable, the only aspect which remained stable was the distal occlusion in the primary dentition which was maintained and transferred to the permanent dentition.
da Silva LP, “Occlusal development between primary and mixed dentitions: a 5 years longitudinal study.” J Dent Child (2008)
- Study purpose: evaluate the variations in occlusal relationships and the influence
- There was a straight terminal plane development (ie from mesial step to Class I and III, and from distal step to Class II).
- Class I canine relationship observed in the primary dentiton was maintained in 91% of the cases, whereas a class III could develop into class I.
- There were no significant changes in the development from the primary to mixed dentiotion. Lower arch crowdidng, however was found in 29% of kids, even in the presence of arch type I and primate spaces.
- The occlusal relationships in the mixed dentition were influenced and followed a pattern determined by the primary dentition. Arch type I and primate spaces favor both development of Class I maloccl and the absence of upper arch crowding.
“Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey.” Proffit, Moray.
- Noticeable incisor irregularity occurs in the majority of all ethnic groups. Only 35% of adults have well-aligned mandibular incisors.
- Mex-Americans, compared to the rest of the pop, incisor irregularity and both severe Class II and II malocclusions are more prevalent (but deep and open bite are less prevalent).
- Over 30% of whites, 11% of Mexis, and 8% of blacks report receiving tx.
- Severe malocclusion is observed more frequently among blacks, which may reflect their lower level of tx.
- Tx is much more freq in higher incomes, approx 5% in lowest income grp and 10-15% in intermediate income grps report being treated.
