Naphtali Brezniak

Root resorption after orthodontic treatment: Part 2. Literature review

All permanent teeth may show microscopic amounts of root resorption that are clinically insignificant and radiographically undetected. Root resorption of permanent teeth is a probable consequence of orthodontic treatment and active tooth movement. The incidence of reported root resorption during orthodontic treatment varies widely among investigators. Usually, extensive resorption does not affect the functional capacity or the effective life of the tooth. Most studies agree that the root resorption process ceases once the active treatment is terminated. Root resorption of the deciduous dentition is a normal, essential, and physiologic process. Permanent teeth have the potential to clinically undergo significant external root resorption when affected by several stimuli. This resorptive potential varies in persons and between different teeth in the same person. This throws doubt on the role of systemic factors as a primary cause of root resorption during orthodontic treatment. Tooth structure, alveolar bone structure at various locations, and types of movement may explain these variations. The extent of treatment duration and mechanical factors definitely influence root resorption. In most root resorption studies, it is not possible to compare the results and conclusions because of their different methods. Further research in this field is necessary to advance the service of the specialty. The question of whether there is an optimal force to move teeth without resorption or whether root resorption may be predictable remain unanswered. This review indicates the unpredictability and widespread incidence of the root resorption phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)

Orthodontically induced inflammatory root resorption. Part I: The basic science aspects.

Orthodontically induced inflammatory root resorption (OIIRR) or, as it is better known, root resorption, is an unavoidable pathologic consequence of orthodontic tooth movement. It is a certain adverse effect of an otherwise predictable force application. Although it is rarely serious, it is a devastating event when it is radiographically recognized. Orthodontics is probably the only dental specialty that actually uses the inflammatory process as a means of solving functional and esthetic problems. Force application initiates a sequential cellular process. We know exactly how and when it is evoked, but we are unable to predict its actual overall outcome. The extent of this inflammatory process depends on many factors such as the virulence or aggressiveness of the different resorbing cells, as well as the vulnerability and sensitivity of the tissues involved. Individual variation and susceptibility, which are related to this process, remain beyond our understanding. We are therefore unable to predict the incidence and extent of OIIRR after force application. This contemporary review is divided into two parts. In Part I, we discuss the basic sciences aspects of OIIRR as a continuation of our previously published work. In Part II, we present the clinical aspects of this subject.

Orthodontically Induced Inflammatory Root Resorption. Part II: The Clinical Aspects

Over the past 10 years, orthodontically induced inflammatory root resorption (OIIRR) has been increasingly recognized as an iatrogenic consequence of orthodontic treatment. With this in mind, orthodontists should take all known measures to reduce the occurrence of OIIRR. The evidence that we present in this review suggests several procedures known today that can avert this phenomenon; however, none of them can be relied on to completely prevent OIIRR. We believe that future studies might clarify the exact cause and course of OIIRR and, hopefully, help eliminate it. In Part I, we discussed the basic sciences aspects of OIIRR; in Part II, we present the clinical aspects of this phenomenon.

Pathognomonic Cephalometric Characteristics of Angle Class II Division 2 Malocclusion

The Class II division 2 (Class II/2) malocclusion as originally defined by E.H. Angle is relatively rare. The orthodontic literature does not agree on the skeletal characteristics of this malocclusion. Several researchers claim that it is characterized by an orthognathic facial pattern and that the malocclusion is dentoalveolar per se. Others claim that the Class II/2 malocclusion has unique skeletal and dentoalveolar characteristics. The present study describes the skeletal and dentoalveolar cephalometric characteristics of 50 patients clinically diagnosed as having Class II/2 malocclusion according to Angles original criteria. The study compares the findings with those of both a control group of 54 subjects with Class II division I (Class II/1) malocclusion and a second control group of 34 subjects with Class I (Class I) malocclusion. The findings demonstrate definite skeletal and dentoalveolar patterns with the following characteristics: (1) the maxilla is orthognathic, (2) the mandible has relatively short and retrognathic parameters, (3) the chin is relatively prominent, (4) the facial pattern is hypodivergent, (5) the upper central incisors are retroclined, and (6) the overbite is deep. The results demonstrate that, in a sagittal direction, the entity of Angle Class II/2 malocclusion might actually be located between the Angle Class I and the Angle Class II/1 malocclusions. with unique vertical skeletal characteristics.

A comparison of three methods to accurately measure root length.

Measuring the severity of root shortening after orthodontic treatment is a common problem in the dental fields as well as in litigation, legislation, and the ethics arena. The most common method to evaluate root length shortening is by using periapical radiographs. Surprisingly, root elongation after orthodontic treatment in adult patients was reported in the past. The aims of this study were to measure the effects of angular changes between the tooth and the film on the length of the image of a tooth model, to compare three methods to accurately measure root length in different films, and to find the most accurate reference points on the tooth for calculating root lengths. Five amalgam dots were placed on an acrylic model of a maxillary central incisor: ie, most apical, most incisal, mesial CEJ, distal CEJ, and most apical CEJ on the buccal side. The tooth model was placed in a special jig and radiographed at four different film-to-tooth angulations. Root and crown lengths were measured on both the model itself and on a computer monitor displaying the image that resulted from scanning the film into the computer. The results revealed that angular changes between the tooth and the film affect the measured tooth length. The midpoint between the mesial CEJ point and the distal CEJ point (median CEJ) was the best reference point for measuring root length. This was true when the calculations were done with the rule-of-three formula.

Root resorption following treatment with aligners.

Can orthodontically induced inflammatory root resorption (OIIRR) be the result of Invisalign treatment? Since OIIRR was first described in the literature, orthodontists have been looking for a treatment procedure where no root shortening will occur. In the past decade, Invisalign orthodontic treatment has become very popular, and there is no description of OIIRR after this treatment. Therefore, it might be incorrectly concluded that the body is immune to this type of orthodontic treatment modality and no OIIRR appears as a result of this treatment. The following case report demonstrates an aspect of the complexity of OIIRR.

Israeli cephalometric standards compared to Downs and Steiner analyses.

A sample consisting of 40 young Israeli adolescents, 18 males and 22 females, was examined cephalometrically. The subjects were classified as Angle Class I, with less than three millimeters of crowding and an orthognathic profile. Steiner and Downs analyses were performed for all subjects. Each analysis was done both manually and by using a computer. The computerized results were processed and subjected to statistical tests. The Israeli sample is characterized by a convex profile, a retrusive mandible, a steep mandibular plane and protrusive incisors.

Angular Changes and Their Rates in Concurrence to Developmental Stages of the Mandibular Second Premolar

In the early developmental stage of the mandibular second premolar (MnP2), it is not unusual to find the tooth extremely angulated to the lower border of the mandible, as seen in the panoramic roentgenogram. On eruption, the tooth, in most cases, is close to being upright. However, impaction or other types of malocclusions due to its ectopic eruption are not rare. This study follows the angular changes of the MnP2 during development. Two hundred two panoramic roentgenograms of 101 patients were retrospectively analyzed. All patients had two sequential films with a minimal time interval of nine months. Each MnP2 was traced, and its developmental stage as well as its angulation to the lower border of the mandible was registered. We found that normally more MnP2 are distally (56.5%) than mesially (25%) inclined. There is a statistically significant difference in the inclination of the teeth during their development from stage D to stage F (D = 75.17 degrees +/- 15.25 degrees, E = 79.35 degrees +/- 12.18 degrees, F = 83.38 degrees +/- 10.79 degrees). The average amount of total angular change rate of the MnP2s from stage D to stage G is 0.09 +/- 0.25 degrees/mo, and the absolute angular change rate is 0.19 +/- 0.25 degrees/mo.

Severe high Angle Class II Division 1 malocclusion with vertical maxillary excess and gummy smile: a case report.

Severe Class II Division 1 malocclusion with vertical maxillary excess and gummy smiles can be treated in several ways. Early orthodontic treatment with vertical control may decrease the malocclusion as well as improve the appearance. In severe cases, orthognathic surgery might be the optimal solution. The following case report describes a patient with a severe gummy smile, where the final esthetic improvement was achieved by using a periodontal procedure after orthodontic treatment.

The Accuracy of the Cementoenamel Junction Identification on Periapical Films

In the study of orthodontically induced inflammatory root resorption, many researchers use the cementoenamel junction (CEJ) as a bisecting reference point to measure the amount of root shortening. The accuracy of the identification of the CEJ point might affect the conclusions of those studies. This study aims to find the effects of angular changes between the tooth and the film on the validity and reproducibility of identifying three different CEJ points, ie, the most apical CEJ point between the crown and the root, the most mesial CEJ point, and the most distal CEJ point. An extracted maxillary central incisor was placed in a special jig and radiographed at four different tooth to film angulations. Eight examiners were asked to identify the buccal and palatal CEJ, whereas six examiners were asked to identify the mesial and distal CEJ points, all on a computer monitor. The distances between the identified points and the apex were computed and compared with the actual ones. The angular changes between the tooth and the film did have a statistically significant effect on the identification of some of these CEJ points. The difference was significant on the identification of the buccal and palatal points but not on the mesial and the distal ones.