Missing and unerupted teeth in osteogenesis imperfecta

Abstract

Introduction: Osteogenesis imperfecta (OI) is a genetic disorder characterized by bone fragility and craniofacial and dental abnormalities such as congenitally missing teeth and teeth that failed to erupt which are believed to be doubled in OI patients than normal populations and were associated with low oral health quality of life. However, the etiology of these abnormalities remains unclear. To understand the factors influencing missing and unerupted teeth, we investigated their prevalence in a cohort of OI patients as a function of the clinical phenotype (OI type), the genetic variant type, the tooth type and the onset of bisphosphonate treatment.

Method: A total of 144 OI patients were recruited from The Shriners Hospital, Montreal, Canada, between 2016 and 2017. Patients were evaluated using intraoral photographs and panoramic radiographs. Missing teeth were evaluated in all patients, and unerupted teeth were assessed only in patients ≥15 years old (n = 82).

Results: On average, each OI patient had 2.4 missing teeth and 0.8 unerupted teeth, and the most common missing and unerupted teeth were the premolars and the upper second molars, respectively. These phenomena were more prominent in OI type III and IV than in OI type I, and were not sex or age-related. Missing teeth were significantly more common in patients with C-propeptide variants than all other variants (p-value <0.05). Unerupted teeth were significantly more common in patients with α1 and α2 glycine variants or substitutions than in those with haploinsufficiency variants. Early-onset of bisphosphonate treatment would significantly increase the risk of unerupted teeth in patients with OI types III and IV (OR = 1.68, 95% CI (1.15-1.53)).

Conclusion: The prevalence of missing and unerupted teeth at the tooth type level in OI patients varies according to the nature of the collagen variants and the OI type. These findings highlight the role of collagen in tooth development and eruption.

Keywords: Agenesis; Bisphosphonate; Missing teeth; Osteogenesis imperfecta; Rare disease; Retained teeth; Tooth development; Tooth eruption; Unerupted.

Fig. 1.

Intraoral photographs (a–e) and panoramic radiograph (f) of a 17 years old male with OI type IV. The intraoral photos were taken from different directions: (a) upper occlusal (b) lateral left (c) lower occlusal, (d) facial, (e) lateral right. The photos reveal tooth discoloration (arrowed), as well as class III malocclusion, open bite, and posterior crossbite. The radiograph (f) shows missing upper second premolars (○), unerupted teeth (◊), and retained deciduous molars (●).

Fig. 2.

Bar charts representing the number of missing/present and unerupted/erupted teeth in the study population as a function of the type of OI (a) and genetic variants (b). The brackets indicate significant differences in the prevalence of missing and unerupted teeth as a function of the genetic variants (p-value<0.05). The prevalence of missing teeth was significantly higher among teeth with C-propeptide variants than in those with other variants, and significantly lower among teeth with the α1 haploinsufficiency variant (p-value<0.05). The prevalence of unerupted teeth was significantly lower in the haploinsufficiency variant than in those with the glycine substitution variant (p-value<0.05).

Fig. 3.

The prevalence of missing teeth at the tooth level. a) The prevalence of missing teeth evaluated in every type of genetic mutations, b) the prevalence of missing teeth in different types of OI.

Fig. 4.

The prevalence of unerupted teeth at the tooth level. a) the prevalence of unerupted teeth in every type of genetic mutations. b) The prevalence of unerupted teeth in different types of OI.

Fig. 5.

The mean of age when Bisphosphonate treatment was first started in patients with different OI types. *Patients with OI type I were significantly older than those with OI types III and IV in the age when bisphosphonate was first started (p < 0.05).