unique and specific phenotype Characterized by diminished and dysplastic root formation and a narrow abnormal pulp champe

1. MOLAR ROOT-INCISOR MALFORMATION:
CONSIDERATIONS OF DIVERSE
DEVELOPMENTALAND ETIOLOGIC FACTORS
Wright et al (2016 )
Done by R2 (Mohammad)

2. Introduction
• ( MRIM) unique and specific phenotype Characterized by
diminished and dysplastic root formation and a narrow
abnormal pulp champer of the first permanent molars( 2nd
primary molar and permanent anterior teeth are affected
in some cases).
• Genetic defects and environmental influences can cause
failure of tooth development or abnormal morphologic
changes of the tooth.

3. Introduction
• Hereditary Dentin defects classified into:
1. Dentinogenesis imperfecta (DGI).
2. Dentin Dysplasia (DD).
• These hereditary conditions are associated with
abnormal dentin mineralization and varying degrees of
changes in tooth morphology.
• DGI type I is associated with osteogenesis imperfecta,
whereas the clinically similar DGI type II is not associated
with a syndrome and is caused by mutations in the gene
encoding dentin sialophosphoprotein(DSPP).

4. Introduction
• Individuals with DGI often have dental root structures that
are diminished in size and appear sharp and “ tent peg-
like” .
• The phenotype in DD type I is characterized by clinically
normal-appearing tooth crowns and markedly altered
dentin formation (waterfall appearance), pulp chamber
obliteration, and abnormal to nearly missing root
development

5. Introduction
• Truncated Root Formation
 mutations in the IFIH1 gene and Singleton-Merten
syndrome.
• Tumoral Calcinosis
 can have short bulbous roots. TC is caused by mutations
in the GALNT3 gene.
• Sponastrime Dysplasia and Bardet-Biedl Syndrome
 seen with Short dental roots
• Kenny-Caffey syndrome
 caused by mutations in the TBCE gene, is associated
with abnormal root formation.

6. Introduction
• Many environmental stressors and conditions, are
associated with the abnormal formation of the tooth roots.
trauma, infection, radiation, and certain
chemotherapeutic agents for malignancies during early
childhood can result in abnormal tooth and tooth root
development.
• Severe infections, such as those occurring in Steven-
Johnson syndrome or meningo-coccemia, can result in
abnormal root formation.

7. Methods
• The study protocol approved by SNUDH and the
University of North Carolina(NC).
• Radiographs taken between February 2012 and May
2013 at SNUDH . Additional cases from (NCU).
• longitudinal follow-up was available.
• Generalized root malformation due to anticancer therapy
were excluded. And 30 cases (18 M, 12 F) were selected
for this report.
• Teeth were decalcified, sectioned, stained with
hematoxylin and evaluated with light microscope.

8. RESULTS

9. Result

10. Histologic evaluation
• The pulp chambers all had
a greatly reduced
dimension between the
roof and floor of the pulp
chamber.
• Secondary dysplastic pulp
area had frequent
inclusions, which were not
present in normal
appearing pulp.

11. DISCUSSION
• The first permanent molars were always affected (100%),
making primary feature of this unique developmental
defect of the dentition.
• Secondary feature defects included second primary
molars, which affected in (50%) of the cases. Affected
permanent canines (13%) of cases.
• Most of the MRIM cases suggesting these root
malformations are caused by a secondary effect of the
systemic stressors

12. CONCLUSIONS
• In this report there is a diverse range of severity related to
the teeth affected and the extent of the malformation
(e.g., root/crown malformation).
• Clinicians identifying cases of MRIM should carefully
evaluate them for an increased risk for ectopic eruption
and permanent incisor malformations that can lead to
pulpal necrosis.