**2. Methods**

The author for the first time provides a self-directed dento-maxillofacial radiology atlas with focus on the developmental dental defects. The atlas that aims at demystifying the reporting and the differential diagnosis and diagnosis of the subject area utilizes a collection of radiographs to report radiographic images and arrive at both a differential diagnosis and a definitive diagnosis.

Each radiograph is depicted as a plate and as such consecutively numbered from 1 to 37.

Each plate is given a heading that concurs to the definitive diagnosis. This heading is depicted in RED.

The radiographic images are then followed by specific questions including instructions for the reader to point at specific areas of the images. These questions are depicted in BLACK.

The questions are then repeated in BOLD BROWN with the answers to the questions displayed adjacent to it and depicted in RED.

At the foot of each radiographic plate is a reference or list of reference that is aimed at providing obvious reference to each plate. These references are highlighted in Green.

All questions are strictly radiographically oriented and has strong clinical inclination and to include the use of both the radiographic and clinical information to arrive at a definitive diagnosis and clinical treatment or management. All questions and pointers are completely answered for the benefit of the student's e-based learning without the need of a lecturer.

All the wordings of the manuscript are those of the author and have not been copied from any previous text.

The students on repeated reading of the text and correlation of such information with each preceding radiographic image will completely understand the topic without the need of a tutor.

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*


See arrow A.

5.What is it called?

Dens invarginatus (dens in dente).

6.List two clinical considerations of this condition.


1.Describe the lesion.

2.What is it called?

**Figure 1.** *Periapical radiograph showing dens inverginatus.*


The occlusal radiograph shows a well-defined and well-corticated, heartshaped unilocular radiolucent lesion with septations within it in the anterior region of the palate. The lesion is about 35 25 mm and intimately related to the apical region of the anterior teeth.

6.What is it called?

Nasopalatine duct cyst or the incisive canal cyst.

	- a. Routine radiography (occlusal radiograph)
	- b. Swelling under a denture
	- c. Painful or infected swelling in the anterior maxilla

No, it is actually a developmental non-odontogenic cyst? (**Figure 2**) [2].


**Figure 2.** *Occlusal radiograph showing nasopalatine duct cyst (see arrows).*

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

4.Use an arrow to point at the anomaly.

See white arrow B.

5.What is it called?

Anodontia.

6.What are the clinical implications for this condition?

Since the permanent successor is missing the bone in the area is usually deficient and extraction and implant placement may not be effected easily unless bone grafting is done. Fortunately, this tooth may remain in occlusion throughout life despite it being prone to caries formation and periodontal disease (**Figure 3**) [2].

This patient has had no extractions


See the arrows.


#### **Figure 3.**

*Part of a dental panoramic tomogram (DPT) showing over-retained deciduous second molar and missing second premolar in the lower jaw (see arrows).*

In all the four quadrants, some deciduous teeth are over retained with the permanent successors absent in the bone. These over-retained deciduous teeth are the canine teeth in the upper jaw and the first molars in the mandible. It is not unlikely that the edentulous space in the maxilla is as a result of permanent teeth that never formed (**Figure 4**) [2].


See the arrow.

6.What is it called?

Mesiodens.

7.What do you see clinically?

A diastema caused possibly by a rotated miniature/defective supernumerary incisor.

8.Do a report on this radiograph.

This is a dental panoramic tomogram (DPT) of a child in mixed dentition stage—the upper jaw in the anterior region presents with a microdont supernumerary tooth with an upwardly directed crown, which is impinging on the root of the central incisor on the right side to cause the incisor to rotate.

Diagnosis: Mesiodens that is causing a pressure effect on the central incisor **(Figure 5)** [2].

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

**Figure 5.** *DPT of a patient in mixed dentition stage showing a maxillary mesiodens tooth (see arrows).*


See arrow.

5.What is this called?

Macrodont.

6.Explain the clinical considerations of this particular situation:

1. Inability to erupt into the arch.


See the arrow.

**Figure 6.** *Part of a DPT showing a Macrodont (see arrows).*

	- 1.High possibility of development of periodontal disease.
	- 2.High possibility of forming a carious lesion.
	- 3.Technical extraction, should it be a part of the surgical extraction of four wisdom teeth **(Figure 7)** [2].
	- 1.Germination
	- 2.Fusion

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

**Figure 7.** *Periapical radiograph showing a microdont tooth (see arrows).*

7.What is the common name for the conditions you have named?

Both differential diagnosis above are called double teeth or twinning.

8.How do you confirm a diagnosis?

The confirmation is purely clinical—this is by counting the number of teeth in the arch. If the numbers of teeth is normal, then it is fusion; however, it is germination if the number of teeth is more (**Figure 8**) [2].


See the arrow.

5.What is it called?

Dens inverginatus.

6.What are the clinical implications of this condition?

1. Infection of the periapical tissues without any carious lesion.


**Figure 8.** *Periapical radiograph double teeth in relation to the upper central incisor tooth (see arrows).*

bridge. Usually, root canal treatment is commenced, only to fail because of the structural defect (DDD), which existed and was undetected before the commencement of root canal (**Figure 9**) [2].

	- 1.Large root canal of the tooth (pointed to).
	- 2.Large pulp chamber and canal.

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

**Figure 9.** *Periapical radiograph showing s dens inverginatus (see arrows).*

	- Taurudontism.
	- 1.Difficulty in extraction.
	- 2.Difficulty in endodontic treatment (obvious).

9.What other implication is this condition ascribed to?

Forensic implication.

	- Unique non-coincidental forensic finding at postmortem (**Figure 10**) [2].
	- 1.Attrition,
	- 2.Abrasion,
	- 3.Dentinogenesis imperfect,
	- 4.Amelogenesis imperfect,
	- 5.Erosion.

#### **Figure 10.**

*Part of a DPT showing the lower second molar affected with taurodontism (see the arrow showing the enlarged and rectangular pulp chamber and low furcation involvement).*

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

8.What are they collectively called?

Tooth tissue loss.

9.Use an arrow to point to a tooth tissue that will require radiological monitoring for the progression of this disease

See the three arrows pointing to the pulp.

10.Which of this list in #1 above are the developmental dental defects?

Amelogenesis imperfecta and dentinogenesis imperfecta.

11.What do you expect to see in these teeth?

Obliteration of pulp canal/cavity.

12.Do you now understand that tooth tissue loss is both a clinical and radiological diagnosis and that amelogenesis and dentinogenesis imperfecta are conditions with tooth tissue loss?

Yes! (**Figure 11**) [2].


**Figure 11.** *Periapical radiograph showing tooth tissue loss (see arrows).*


A microdont tooth (third molar).

6. Is this tooth still developing?

Yes.

7.Why do you think it is not developing?

The roots are not fully formed.

8.Point to other pathology relating to this tooth and explain it briefly?

There is a pericoronal radiolucency (arrow #1), which may be the initial stage of a cystic degeneration—should a cyst form, it is likely to be a dentigerious cyst. Also, an ameloblastoma may develop around the tooth. However, because the roots are still developing, there may be some eruptive force, which may direct the tooth to occlusion (**Figure 12**) [2].


#### **Figure 12.**

*Periapical radiograph showing a microdont third molar tooth. See the yellow and black arrow delineating the boundaries of the developing cyst. (see arrows).*

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

4.Point to the main anomaly in this radiograph.

See arrow pointing to the bent tooth.

5.What is it called?

Dilaceration of an upper central incisor tooth.

	- 1.The need for a surgical extraction,
	- 2.Difficulty in the surgical extraction with the possibility of fracture of the apical 1/3rd of the roots,
	- 3. Inability to effect a root canal treatment (**Figure 13**) [2].

Regional odontodysplasia.

**Figure 13.** *Occlusal radiograph showing a dilacerated maxillary central incisor (see arrows).*

7.Explain it.

This is a very uncommon developmental dental defect that is usually localized to a quadrant of the mouth/jaw. It is a condition with no hereditary affiliations, with no race predilection, but affecting more females than males. The enamel, dentine, and pulp of the teeth are affected to the extent that the affected teeth do not develop properly. The teeth will as such appear more radiolucent than normal.

8.What other name is this condition called?

Ghost teeth (**Figure 14**) [2].


A dental periapical radiograph of the anterior teeth showing malformed central and lateral incisors with enlarged pulp cavity and with severe teeth tissue loss of developmental origin. The coronal enamel is very inadequate; the dentine and pulp cavities are also poorly developed.

6.What is your diagnosis?

Regional odontodysplasia or dentinogenesis imperfecta.

7.What are the main reasons for making this diagnosis?

Poorly developed enamel, dentine, and pulp tissue with tooth tissue loss. The changes in the pulp cavity can be construed as obliteration of the pulp cavity.

**Figure 14.** *DPT of a child showing ghost teeth in the anterior region of the maxilla. (See arrows).*

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

	- 1.Non-syndrome dentine dysplasia.
	- 2.Osteogenesis imperfect.
	- 3.Dentinogenesis imperfect (**Figure 15**) [2].

See the pointing arrow.

	- Wondering tooth.
	- 1. Infection,
	- 2.Loss of coronal eruptive force,
	- 3.Associated lesion/tumor,
	- 4.Congenital or hereditary.
	- 1.Resorption of adjacent root,
	- 2.Bucco-lingual expansion/swelling of the mandible,
	- 3.Formation of dentigerous lesion,
	- 4.Ameloblastoma formation,
	- 5.Weak point in which fracture can easily occur following slight trauma (**Figure 16**) [2].

**Figure 16.** *Periapical radiograph showing a wondering tooth (note the beginning of cystic degeneration around the tooth).*

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*


Imperfect enamel of all the molar teeth (both primary and secondary dentitions).

9.What are your differential diagnoses?

1.Amelogenesis imperfect,

2.Dentinogenesis imperfect,


Yes (**Figure 17**) [2].


There are six or more missing teeth.

Look at the arrows and circles.

The arrows points to the over-retained deciduous teeth without any permanent successor and also edentulous spaces.

#### **Figure 17.**

*Bitewing radiograph showing tooth tissue loss in both the upper and lower molar teeth (both the deciduous and permanent dentition are involved).*

The circular corticated regions around the third molar attest to the developing status of the third molars, which can also be used as a mark for the determination of the age of this patient.

	- 1.Sporadic hypodontia,
	- 2.Hypodontia/hypodontia associated with syndrome (i.e., ectodermal dysplasia),
	- 3.Non-syndromal hypodontia or oligodontia.

This is the dental panoramic tomogram of a child who is partially edentulous.

The deciduous teeth pointed to by the arrows are over-retained with the permanent successors absent within the bone.

The third molars are forming within the bone. Some edentulous spaces are present due to non-development of teeth. The errors in this radiograph are that of severe bowing due to the fact that the patients neck is far too in and down in the machine (**Figure 18**) [2].

1.Describe this radiograph.


*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

**Figure 18.** *DPT showing various over-retained deciduous teeth and edentulous regions (areas where no permanent teeth erupted) (see arrows).*


The periapical radiograph shows the bulbous roots of teeth #16 and 18, with complete obliteration of the pulp cavity. The retained roots of the tooth #15 have its pulp cavity also obliterated. The edentulous space of tooth #17 is too long but has adequate amount of bone height to receive an implant. The instanding teeth have no carious lesions or periodontal lesions.

7.List the most significant single diagnostic finding.

Pulp obliteration.

8.What is your diagnosis?

Dentine dysplasia or dentinogenesis imperfect.

9.Could this be related to a syndrome?

Yes.

10.What is the name of the syndrome?

Osteogenesis imperfecta (**Figure 19**) [2].


**Figure 19.** *Periapical radiograph showing molar teeth and retained roots with pulp obliteration.*

5.Describe this radiograph.

This dental periapical radiograph of the anterior teeth shows all the four anterior teeth to have suffered tooth tissue loss. These teeth also have complete obliteration of the pulp cavity.

6.List the most significant single diagnostic finding.

Tooth tissue loss and complete obliteration of the pulp cavity.

7.What is your diagnosis?

Dentinogenesis imperfecta.

8.Make a list of differential diagnosis.

1.Amelogenesis imperfect.


Presence of pulp obliteration (**Figure 20**) [2].


See the short arrows pointing to the teeth tissue loss and the longer arrows pointing to the obliteration of the pulp cavities.

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

**Figure 20.** *Periapical radiograph showing tooth tissue loss and pulp obliteration.*

4.Describe the radiograph.

This is a periapical radiograph of the maxillary anterior teeth showing tooth tissue loss of #11, 12, 21, 22 and obliteration of the pulp cavity/canal of all the four incisors. The periodontal membrane space and periapical regions are intact (**Figure 21**) [2].


See all the arrows.

**Figure 21.** *Periapical radiograph showing tooth tissue loss and pulp obliteration of upper incisors.*

7.Describe the radiographic findings.

Bilaterally is a set of double horizontally impacted third molars, with evidence of pressure effect on the second molars bilaterally with resultant crowing of the anterior teeth. The main issue is that instead of 16 teeth in the mandible, there are a total of 18 teeth. The maxilla is not exempted from these findings except that the bilateral distomolar are microdont and are not putting any pressure on the second molars.

	- 1.Bilateral germination of the third molars with double horizontally impacted teeth on each side of the mandible.
	- 2.Bilateral unerupted maxillary microdont third molars.

By counting the number of teeth in the jaw.

10.Name two differential diagnoses.

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

1.Fusion.

	- 1.Damage to the inferior dental nerve and
	- 2.Fracture of the mandible (unilateral or bilateral).
	- 1.By surgically fracturing the jaw and dissect out the wisdom teeth (orthognathic surgical removal) and
	- 2.Removal of the more occlusal third molar and leaving the deeper ones in place (**Figure 23**) [2].

Obliteration of the pulp cavity/chamber.

**Figure 22.** *DPT showing bilateral double third molar teeth, consistent with germination.*

*Clinical Concepts and Practical Management Techniques in Dentistry*

**Figure 23.** *DPT showing bilateral double third molar teeth, consistent with germination.*

6.List all the possible differential diagnosis based on this generalized anomaly:


7.What is the resultant effect of all these differential diagnoses?

Tooth/teeth tissue loss and progressive pulpal obliteration.

8. If I provide you with a family history of multiple fractures of long bone and hip bones, what would your diagnosis be?

Dentinogenesis imperfecta with or without dentine dysplasia in a patient with osteogenesis imperfecta (**Figure 24**) [3].


3.What is the non-DDD called\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

4.Give one differential diagnosis for the non DDD\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

#### **Figure 24.**

*DPT showing obliteration of pulp of all the teeth, a feature consistent with dentinogenesis imperfect in this case of osteogenesis imperfecta.*


See arrow.

7.Point to one non-developmental dental defect using a medium sized arrow.

See arrow.

8.What is the non-DDD called?

Cervical abrasion.

9.Give one differential diagnosis for the non DDD.

Cervical burnout.

10.Why in this situation this differential diagnosis will not be considered any further?

There is no other tooth distal to the tooth affected by the cervical abrasion.

11.What are the three possible differential diagnoses for the DDD that you pointed to with the small-sized arrow?

1.Fusion,


12.What are they collectively called?

Double teeth or twinning.

13.The propositus family pedigree shown in Appendix I depicts the familial history of this DDD. On clinical examination of the index case, the number of teeth counted in the mandible is not increased. Provide one definitive diagnosis (**Figure 25**) [2–4].

Fusion.

This is a 37-year-old female. The only tooth ever removed by this patient is the upper first molar on the left side.

1.What is your diagnosis?

2.Can this diagnosis be related to a syndrome?

3.Name one such syndrome.

This is a 37-year-old female. The only tooth ever removed by this patient is the upper first molar on the left side.

1.What is your diagnosis?

Hypodontia or ologidontia.

2.Can this diagnosis be related to a syndrome?

Yes?

#### **Figure 25.**

*Periapical radiograph showing twining of lower incisor. Also note the cervical tooth tissue loss of the distal aspect of the canine tooth due to tooth brushing abrasion. The teeth involved in the twining have been protected from the abrasion. (See arrows).*

*The Radiology of Developmental Dental Defects Demystified: An e-Based Learning System DOI: http://dx.doi.org/10.5772/intechopen.101435*

3.Name one such syndrome.

Ectodermal dysplasia (**Figure 26**) [2–4].

Point at the developmental dental defects in the periapical radiographs shown above.

1.What are they called? \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

2.What other names have they acquired? \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

3. In which teeth are they most commonly found?

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

4.Can multiple teeth be involved? \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
