CLINICAL PRACTICE
CASE REPORT |
The labiogingival notch
An anatomical variation of clinical importance
YOCHEVED BEN-BASSAT, D.M.D. and
ILANA BRIN, D.M.D.
 |
ABSTRACT
|
|---|
Background. The labiogingival notch is a developmental phenomenon affecting the maxillary central incisors. Clinically, it can be easily misdiagnosed and improperly treated. Thus, it is important for dentists to recognize this condition.
Case Descriptions. The authors describe two cases of misdiagnosed labiogingival notch on a maxillary central incisor. In one case, the notch was misinterpreted as a carious lesion and placement of a restoration was advised. In the second case, external resorption was suspected and forced eruption of the incisor was requested. In both cases, no treatment was needed.
Clinical Implications. Misdiagnosis of this developmental phenomenon may lead to unnecessary invasive interventions. Because of this, clinicians need to be aware of this clinical variant.
In this era of esthetic dentistry, great care is given to the healthy gingival margin: its contour, height and relationship with the enamel surface.1 It is well-known that the shape of the gingival margin is strongly related to the underlying crown contour. Thus, an important goal of restorative dentistry is to establish biologically compatible crown contour as a basis for healthy and esthetic gingival anatomy.2 The gingival area also is of major importance to orthodontists in their efforts to establish an esthetic smile.
The labiogingival notch is a developmental phenomenon that can be easily misdiagnosed and improperly treated.
In most people, the natural anatomy of the maxillary incisor crown provides the proper foundation for an esthetic gingival outline. However, any surface irregularity may have an impact on the gingival contour. We3 described an anatomical variant of the maxillary central incisor that appears as a labiogingival notch affecting gingival contour. The labiogingival notch appears as an enamel depression close to the cementoenamel junction, whose depth varies from a shallow depression, which can be identified primarily by probing, to a deep groove. The gingival margin closely follows the enamel contour, appearing almost normal in the case of a shallow notch, while in the case of a deep notch, it acquires an irregular contour because of extension of the gingival tissue into the defect.
In a population survey, we3 examined the dentition of 1,880 Israeli schoolchildren (948 boys and 932 girls) who had a total of 3,760 fully erupted permanent central incisors. We found a labiogingival notch in 123 of the children, for a 6.5 percent prevalence on at least one central incisor. In 96 (5.1 percent) of the children, the notch appeared unilaterally, while in 27 children (1.4 percent), the notch appeared bilaterally (Figure 1
). We observed no predilection for facial side in the case of a unilateral shallow notch, but found a left-side predominance in the case of a unilateral deep notch. In addition, we found no significant difference between the sexes in regard to prevalence of the notch.
We were unable to directly observe the entire extent of the notch in any of the affected teeth because of its subgingival extension. None of the clinically oriented recent literature describes the notch in detail. In a chapter about dental root morphology, Kovacs4 described a "fossacoronoradicular" anomaly. He noticed that in cases in which this feature was present, the cementoenamel junction "instead of showing a bend toward the crown as it generally does, was divided into two often unequal parts and showed at that place a hollow which was nearly always present in the crown and very often in the root." Kogon,5 who examined 1,382 extracted central incisors, described the appearance of a palatoradicular groove on the labial surface of two teeth. Our clinical observation of the labiogingival notch appears to be closely related to the defects described by Kovacs4 and Kogon.5
The purpose of this report is to explore possible clinical problems related to the labiogingival notch, which are highlighted by the following case reports.
|
CASE REPORTS
|
|---|
Case 1.
A 13-year-old girl was referred by her orthodontist (I.B.) to a general dentist for a routine examination before placement of orthodontic appliances. The orthodontist had observed a labiogingival notch during the initial orthodontic examination (Figure 2) and gave the patient special instructions for oral hygiene in this sensitive site. The general dentist misdiagnosed the enamel defect as a carious lesion and suggested that a restoration be placed.
The patient’s parents, who had been informed by the orthodontist about the existence of the notch, sought a second opinion from the Department of Pediatric Dentistry, HU-Hadassah SDM, Jerusalem, Israel, regarding the need for restorative treatment. The pediatric dentist considered the notch to be a developmental enamel defect due to a possible injury in early childhood. He recommended that no treatment be provided except for meticulous oral hygiene practice.
Case 2.
A 9
-year-old boy was admitted to the endodontic department, HU-Hadassah SDM, Jerusalem, because of dental injury to a central incisor involving the enamel and dentin. Radiographic examination revealed an area of external root resorption. In addition, the resident on duty noticed a defect on the labiogingival margin of the injured central incisor at the clinical examination. Because of suspected cervical resorption, the endodontist attempted to explore further by inserting retraction floss (Figure 3A). He then referred the patient to one of us (Y.B-B.) for a forced eruption of the affected incisor to expose the "resorbed" area and attempt to stop the "resorptive" process. However, insertion of an explorer into the defect revealed sound enamel and suggested the presence of a developmental defect, namely the labiogingival notch (Figure 3B). We recommended no treatment for this enamel irregularity.
View larger version (94K):
[in this window]
[in a new window]
|
Figure 3. A. Retraction floss inserted for exploration of a cervical defect. B. After inserting the explorer, the clinician diagnosed the defect as a developmental labiogingival notch.
| |
|
DISCUSSION
|
|---|
Brin and colleagues6 first observed the labiogingival notch in a population study of children who experienced injury to their deciduous incisors. Although trauma to these teeth was suspected as a possible etiologic factor in this phenomenon, the authors found no evidence of a correlation between the appearance of the labiogingival notch and previously encountered trauma to the deciduous dentition.
Several years later, we conducted a population survey of a large random sample and recognized the notch as a developmental defect.3 That study also revealed that the only problems related to the labiogingival notch besides the slight esthetic irregularity were plaque accumulation, staining and initial caries in three teeth (2.4 percent of all of the affected teeth). However, the two cases presented above suggest that misinterpretation of this developmental phenomenon may lead to unnecessary invasive procedures.
Thus, we believe it is important to consider this anatomical entity in the differential diagnosis of enamel defects. In most cases, no invasive intervention is needed. Because no long-term follow-up of patients with a labiogingival notch was conducted in the study described above,3 we do not know if this defect predisposes the tooth to periodontal problems. However, clinicians should consider the defect a locus minoris resistentiae (that is, a site of lessened resistance) and follow up accordingly. In cases of unesthetic appearance of the incisors, placement of a restoration and gingival recontouring may be considered.
|
CONCLUSION
|
|---|
We have described the phenomenon of the labiogingival notch on maxillary central incisors. The two cases presented here illustrate the potential for misdiagnosis. We draw the attention of dentists to this phenomenon for consideration as a possible site of lessened resistance.
View larger version (148K):
[in this window]
[in a new window]
|
Dr. Ben-Bassat is a clinical senior lecturer, Department of Orthodontics, HU-Hadassah SDM, P.O. Box 12272, Jerusalem, 91120, Israel, e-mail "yocheved{at}md.huji.ac.il". Address reprint requests to Dr. Ben-Bassat.
| |
View larger version (129K):
[in this window]
[in a new window]
|
Dr. Brin is a clinical associate professor, Department of Orthodontics, HU-Hadassah SDM, Jerusalem, Israel.
| |
|
REFERENCES
|
|---|
- Kokich VG, Nappen DL, Shapiro PA. Gingival contour and clinical crown length: their effect on the esthetic appearance of maxillary anterior teeth. Am J Orthod 1984;86(2): 89–94.[Medline]
- Wagman SS. The role of coronal contour in gingival health. J Prosthet Dent 1977;37(3): 280–7.[Medline]
- Brin I, Ben-Bassat Y. Appearance of a labial notch in maxillary incisors: a population survey. Am J Phys Anthropol 1989;80(1):25–9.[Medline]
- Kovacs I. A systematic description of dental roots. In: Dahlberg AA, ed. Dental morphology and evolution. Chicago: University of Chicago Press; 1971.
- Kogon SL. The prevalence, location and conformation of palatoradicular grooves in maxillary incisors. J Periodontol 1986;57(4):231–4.[Medline]
- Brin I, Fuks A, Ben-Bassat Y, Zilberman Y. Trauma to the primary incisors and its effect on the permanent successors. Pediatr Dent 1984; 6(2):78–82.[Medline]
TOP
ABSTRACT
CASE REPORTS
