內文：

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口腔病理科 On-Line KMU Student Bulletin

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原文題目(出處)： An observation study of the frequency of supernumerary teeth in a population of 2000 patients Med Oral Patol Oral Cir Bucal 2007;12:E134-8

原文作者姓名： Ma Isabel Lecco Berrocal ; Jose F. Martin Morales ; Jose Ma Martinez Gonzalez

通訊作者學校： European University of Madrid ; Rey Juan Carlos University ; Madrid Complutense University

報告者姓名(組別)： Int. C組李育儒

報告日期： 2007.12.10

內文：

Abstract 1. Objectives

Characteristics of supernumerary teeth and associated clinical complications 2. Study design

Longitudinal observational study of supernumerary teeth (including location, age ,mechanical complication…etc)within 2000 patient

3. Results and Conclusions

The prevalence(1.05%),the mean age(20.2 years),the common gender(males),the most frequency location(upper maxilla ,especially in retromolar zone),the most common mechanical complication(displacement of adjacent teeth) and the presence of follicular cyst are reported

Introduction

1. Definition of supernumerary tooth (hyperondontia)

Additional number of teeth in an individual (over 20 in deciduous dentition or 32 in permanent dentition)

2. Clinically ,supernumerary teeth cause different complications ,including retention of the primary tooth ,delayed eruption of the permanent tooth ,ectopic tooth eruptions ,tooth displacements ,follicular cysts another alterations.

3. Extraction is the general rule

Koch et al → not extract before the child is 10 years old

Kruger → extraction should postpone until the apexes of adjacent teeth have sealed

Donado → extraction should as soon as possible in order to avoid displacement and delayed eruption of permanent teeth

Patients and Method

1. 2000 patients in the Master of Oral Surgery

2. If the patients have supernumerary teeth ,recording the demographic variables(including age and sex) and clinical-radiographic exploration(EX:

orthopantomography and intraoral X-ray) which present the location(upper maxilla or mandible) and position within the arch of the tooth

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Results

1. 21 patient were seen to present supernumerary teeth(24 teeth), representing 1.05%

2. 79.2% (n=19) in the upper maxilla ; 20.8% (n=5) in the mandible

3. In the upper arch,the most common position is at distomolar level (38%, n=8), followed by the anterior zone(mesiodens) (28.6%).The lesser percentage is the region of the premolars (9.6%) and canines(4.8%)

4. In the mandible, the most frequent position is at premolar (14.8) and distomolar level(4.8%)

5. The great majority (95.8%; n=23) is impacted and only 4.2% (n=1) have erupted 6. The mean age of the patients with supernumerary teeth is 20.2 years (range 7-34

years). And it most commonly happens in the third decade of life. (47.6%) 7. It is more common in males. (71.4%)

8. Mechanical accidents to be the most frequent problems (54%), particularly the displacement of adjacent tooth (39%, n=9), followed by reabsorption of the adjacent tooth in 12.5% and the prevention of eruption in 4.1%.And the mesiodens is most inclined to present such mechanical accidents (54.5%), followed by the premolars (27.3%) and – to a lesser extent – the canines and distomolar teeth.

9. Lastly, 19% of the sample (n=4) presented an associated follicular cyst of these, 50% were circumscribed to premolar location

Discussion

1. The supernumerary teeth may be found in the patient who is syndromic or non-syndromic

2. According to the consulted literature source, the incidence of supernumerary teeth varies between 0.1-3.8% and may research 28% in patients with cleft palate and harelip.

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3. The observation of most possible supernumerary teeth-happening decade may be due to the fact that a large percentage of such teeth tend to be a casual finding in the course of molar extractions conducted in patients in this particular age range.

4. In other studies involving pediatric populations

The frequencies are between 1.28-2.4%. Mainly locates in the premaxilla, especially mesiodens.

5. In other studies involving adult populations

The frequencies are lower (between 0.4%-1%), with an increased location in the maxilla ,though in posterior sectors of the arch.

6. This study is almost similar to the above opinion(mesiodens in children and distomolar in adults)

7. Regarding the gender distribution ,this study coincide with most authors that males are more commonly affected than females .But Doninguez et al have observed no difference between sexes.

8. Most authors consider the most common mechanical accident to be delayed eruption of the adjacent teeth ,while in this study the displacement of the adjacent teeth was more frequent ,followed by reabsorpation and ,finally ,delayed or impossible eruption of the adjacent teeth

9. Lastly, regarding the presence of follicular cysts, this study observed incidence was 19%,slightly higher than other authors such as Ries-Centeno 14.66% and Stafne 6%.

題號題目

1 The most common region where supernumerary teeth happened in maxilla was

(A) Mesiodens

(B) Distomolars

(C) Canines

(D) Premolars

答案(A) 出處：Oral and maxillofacial pathology (second edition P.71)

題號題目

2 The most common age and sex of supernumerary teeth is (A) Male and the first two decades of life

(B) Male and the fourth decade of life (C) Female and the first two decades of life (D) Female and the fourth decade of life

答案(A ) 出處：Oral and maxillofacial pathology (second edition P.71)