Periodontal health of orthodontically extruded impacted teeth. A split-mouth, long-term clinical evaluation.

BACKGROUND: Impaction of front teeth (often upper canines) can result in esthetic, functional, and phonetic problems, in addition to root resorption and chronic or acute infections. Most impacted front teeth can be extruded orthodontically after minor periodontal surgery. The purpose of this retrospective study was to examine the periodontal outcome of surgically exposed and orthodontically extruded impacted teeth compared with the spontaneously erupted contralateral teeth. METHODS: A total of 38 patients, who had been treated by a combined surgical and orthodontic approach (closed eruption technique by same periodontist and 2 associated orthodontists), underwent a periodontal re-examination after 4 to 10 years. Periodontal parameters (plaque and gingivitis indices, probing depth, bleeding on probing, gingival recession and width, bone level, and root resorption) of the orthodontically extruded teeth (test) were scored and compared with those of the contralateral naturally erupted teeth (control) in a masked set-up. RESULTS: No significant differences could be detected between test and control teeth, except for the gingival width, which was 1 mm larger for the spontaneously erupted teeth. CONCLUSIONS: The data indicate that orthodontic extrusion of impacted front teeth does not jeopardize their periodontal health. This procedure appears to be a satisfactory alternative to extraction and/or transplantation.

The effect of muscle transplantation after unilateral partial facial paralysis on craniofacial growth and development: relationship between muscle and nerve histomorphometric findings.

Muscle transplantation has become an indispensable tool to restore the smile in patients with long-standing or congenital facial paralysis. However, little is known of the effect of this surgical intervention on craniofacial growth and development or of the adaptation of the transplant to its recipient site under circumstances of growth. The present study investigates these phenomena in the rabbit model. Twelve-day-old New Zealand White rabbits were randomly assigned to three experimental groups. The control group was used to study normal craniofacial growth and development (n = 15). In the nerve ablation group, unilateral paralysis of the buccal branches of the facial nerve was surgically induced (n = 15). In the transplant group, the surgically induced unilateral paralysis of the buccal branches was immediately followed by a neuromuscular graft (n = 12). All animals were operated on at the age of 12 days, and follow-up evaluations were performed at the ages of 2 months and 6 months. Computerized dorsoventral roentgencephalometric and computed tomography investigations were performed at both ages. Nerve and muscle histomorphometric measurements were performed at the age of 6 months to relate the quality of nerve and muscle regeneration to the growth parameters. The roentgencephalometric measurements revealed that analogous disturbed parameters were present in the nerve ablation and the transplant groups. However, in the transplant group, an additional significant effect of time between 2 and 6 months was seen for some parameters. This resulted in significant differences between the nerve ablation and transplant groups at 6 months for these parameters. Computed tomography measurements showed no significant differences in maxillary or mandibular volume in the transplant group compared with the control or nerve ablation groups. However, a significantly diminished increase in bone volume existed in the transplant group for the time period between 2 and 6 months in comparison with the control and nerve ablation groups. Muscle histomorphometric findings revealed a significant change in muscle fiber composition in the graft compared with the normal latissimus dorsi muscle; this was due to a major decrease in type IIB fibers, with an increase in type I and type IIA fibers. Compared with the normal zygomaticoauricular muscle, the amount of type I fibers was significantly increased. No fiber atrophy was found. Macroscopically, the transplanted muscle failed to increase its length during growth. Nerve histomorphometric findings demonstrated a normal amount of nerve fibers; however, they had significantly decreased diameters and reduced myelin areas. The nerve histomorphometric parameters were related to the muscle histomorphometric findings, which in turn were related to craniofacial growth disturbances. These findings suggested that the main growth differences between the transplant group and the control group may have been due to altered nerve function influencing muscle function. Scar tissue formation and the development of more intense muscle activity later are suggested as the causes of the additional effect of time between 2 and 6 months for the several parameters in the transplant group. Reasons for the failure of complete conversion of the graft to a fast muscle and the failure of the transplant to elongate during growth are discussed.

The effect of unilateral partial facial paralysis on nasofrontal sutural growth: an experimental study in the rabbit.

In a previous study in the rabbit, it was demonstrated that paralysis of the midfacial musculature results in decreased anteroposterior growth of the snout. At the end of growth, these animals showed macroscopically striking similarities to animals with unilateral fusion of the nasofrontal suture. In this study, whether nasofrontal sutural growth is unilaterally restricted in animals with unilateral partial facial paralysis was investigated. A left-sided partial facial paralysis was induced in sixteen 12-day-old New Zealand White rabbits. At the ages of 5, 9, 12, and 17 weeks, four animals were randomly assigned to be killed for analysis of nasofrontal sutural growth. In each animal, the left experimental side was compared with the right control side. By means of histomorphometric measurements, it was shown that diminished sutural growth activity was present on the left paralyzed side in periods of rapid growth. On the other hand, no significant alterations in sutural width were found. These findings seem to explain some of the macroscopic growth alterations (i.e., diminished anterior maxillary length) observed in rabbits with unilateral partial facial paralysis.

Effect of nerve repair after unilateral partial facial paralysis on craniofacial growth and development.

The effect of partial transection, coaptation, and freezing of the left facial nerve on craniofacial growth and development was investigated. Twelve-day-old New Zealand White rabbits were randomly assigned to four groups: control group (n = 15), nerve ablation group (n = 15) with a surgically induced partial facial paralysis, nerve coaptation group (n = 15) with a surgically induced partial facial paralysis treated by immediate microsurgical nerve coaptation, and nerve freezing group (n = 13) with a freezing-induced partial facial paralysis. All animals were operated on at the age of 12 days; follow-up evaluations were performed at the ages of 2 months (end-point prepubertal growth) and 6 months (full grown). Computerized dorsoventral roentgencephalometric analysis and computer tomographic three-dimensional volumetric measurements were performed at both ages. Roentgencephalometric analysis revealed that the growth disturbances of the nerve ablation group and the nerve coaptation group were analogous. In contrast, in the nerve freezing group, hardly any growth disturbances as compared with the control group were seen. The CT volume measurements revealed a significant left-right difference in maxillary volume at the ages of 2 and 6 months in the nerve coaptation group as compared with the control group. Muscle histomorphometric analysis revealed a shift in muscle fiber composition in the nerve coaptation group and the nerve freezing group, with an increase of type I fibers at the cost of type IIA fibers. This shift was significantly less pronounced in the latter than in the former. Nerve histomorphometric analysis revealed a significant increase in the number of nerve fibers in the nerve coaptation group as compared with the control group. In the nerve freezing group, the increase in the number of nerve fibers was not significantly different as compared with the control group and the nerve coaptation group. Both the equivalent diameter and the myelin area were equally reduced in the nerve coaptation and nerve freezing groups. Thus, the nerve coaptation group and the nerve freezing group did not differ significantly in the extent of nerve recovery, although they differed in the extent of muscle recovery. The extent of muscle recovery, in turn, was related to the extent of abnormal craniofacial growth and development. Indeed, the growth and development were hardly abnormal in the nerve freezing group and as abnormal as after untreated paralysis in the nerve coaptation group. Therefore, factors related to nerve regeneration, other than those assessed by nerve histomorphology, were considered to be responsible for these differences between both groups. The duration of the denervation time was regarded to be considerably shorter in the nerve freezing group than in the nerve coaptation group, resulting in the observed improved muscle recovery. The difference in the degree of axonal malalignment between both groups was considered to be negligible, because of the tolerance toward axonal malalignment at neonatal age.

The effect of unilateral partial facial paralysis and muscle ablation on craniofacial growth and development: an experimental study in the rabbit.

The effect of unilateral partial facial nerve ablation and unilateral partial midface muscle ablation on craniofacial growth and development was investigated. New Zealand White rabbits (12 days old) were randomly assigned to three experimental groups: control group, to study normal craniofacial growth and development (n = 15); nerve ablation group, surgically induced unilateral paralysis of the buccal branches of the facial nerve (n = 15); and muscle ablation group, surgical unilateral ablation of the facial muscles innervated by the buccal branches of the facial nerve (n = 12). All animals were operated on at the age of 12 days; follow-up evaluations were performed at the ages of 2 months and 6 months. The age of 2 months represents the endpoint of the prepubertal craniofacial growth and development. At the age of 6 months, the animals are fully grown; therefore, the time period between 2 and 6 months is regarded as the pubertal growth period. Computerized dorsoventral roentgencephalometric (measurement of distances and angles) and computer tomographic (three-dimensional volumetric measurements) investigations were performed at both ages. Additional dry skull measurements were performed to determine more precisely the bone segments involved in the craniofacial growth alterations studied. The obtained results indicated the following. Unilateral partial facial paralysis involving the midface resulted in growth alterations analogous to those seen after unilateral total facial paralysis. The growth alterations were not to be seen as a growth restriction (reduction in bony volume) but as growth misdirections (alterations in shape). Major growth alterations were present in those regions closely related to the facial musculature, namely the nasal, maxillary, and premaxillary regions, resulting in a snout deviation toward the operated side. The growth alterations occurred during prepuberty and remained rather stable during puberty. Morphologic signs of muscle denervation were related to the craniofacial growth disturbances. The growth alterations after unilateral partial facial paralysis were mainly biomechanically induced, as they were analogous to those observed after unilateral midfacial muscle ablation. The fact that after unilateral midfacial muscle ablation at the age of 6 months the severity of the alterations had increased was attributed to the scar formation inherent to the surgical procedure.

Maxillofacial growth after neck burn injury at a young age: an experimental study in the rabbit.

An experimental model was designed to define alterations in the normal mandibular growth process under the influence of postburn neck contractures. Additionally, this craniofacial growth model was used to compare two early treatment modalities of neck burns in their capability to minimize contracture and hence allow for normal mandibular growth and development. Growth implies increase in size as well as change in shape and position. These three aspects of growth were defined accordingly to Björk as rotations. The intramatrix rotation expresses the change in mandibular shape, and the matrix rotation expresses the change in mandibular position relative to surrounding structures. The total rotation expresses both, and together with the measurement of the mandibular length, they represent the increase in mandibular size. Thirty-two 7-week-old rabbits were divided at random in four groups of eight rabbits each and randomized for selection for the 14 operation days defined as t = 0: Group A: controls to define normal mandibular growth Group B: untreated third-degree neck burns Group C: third-degree neck burns treated by a full-thickness skin graft Group D: third-degree neck burns treated by a myocutaneous flap All animals underwent placement of two bone markers in the maxilla. With biweekly intervals, standardized lateral skull roentgenographs were taken until the rabbits reached the age of 21 weeks. In this time period, major growth accelerations including the pubertal growth spurt took place. By the use of 13 reference points and 7 reference lines, rotations and distances were calculated. Statistical analysis of the data was performed. The results show that the normal mandibular length was unaffected in all groups. There were no statistically significant changes in matrix, intramatrix, and total rotations of the mandible and the maxilla. There was a statistically significant difference in the displacement of the mandibular reference point between all groups, suggesting a variable degree of normal backward skull rotation, namely, due to group B. Explanations to be considered concerning the fact that the only minor differences were found in group B: 1. Drawbacks of the animal model: differences in skin texture, postnatal mandibular growth, and head position compared with those of humans. 2. Other functional adaptation mechanisms such as changes in head position, which are recruited at first in adapting to disturbances of homeostasis, were not measured. Soft-tissue compensation probably has overcome major bony deformations. Nevertheless, some drawbacks of the model can be viewed as ideal concerning treatment of neck burns.(ABSTRACT TRUNCATED AT 250 WORDS)

[Optimizing complicated treatments in dental medicine indirectly through the coordination center. Current challenges]. / Optimiser les traitements complexes en médecine dentaire par le biais des centres de coordination. Le nouveau défi.

Patient care and processing of the many tasks surrounding a 'multi disciplinary patient' give problems which are difficult to attend, even in well organised practices. Activities, medical and other, are seen as tasks which are standardised as much as possible. The follow up is delegated to a co-ordination centre. Special developed software supports the co-ordinator(s). There are four stages: 1. introduction of the patient and his team, 2. organisation of the preliminary examinations, 3. the treatment planning involving the organisation of a team conference, the work out of the different treatment proposals and support of the patient while choosing the treatment plan of his choice and 4. the implementation of the treatment plan. Throughout the whole procedure care is taken to have a maximal involvement of the general practitioner. The concept allows him to keep his difficult, yet challenging, patients.

Resorption of the lateral maxillary incisor: assessment by CT.

Computed tomography of the maxillary alveolar arch was performed in three children with delayed eruption of one or both maxillary cuspids. Computed tomography demonstrated close contact between the ectopically localized and nonerupted canine and the lateral incisor. The lesion was unilateral in two patients and bilateral in one. In two patients resorption of the lateral incisor root was demonstrated. Moreover, CT permitted exact determination of the extent of the lesion by differentiating between superficial cementodentine resorption limited to the cementodentine (superficial resorption) and resorption extending into the pulpal canal (pulpal canal involvement).

The effect of the amount of protrusion built into the bionator on condylar growth and displacement: a clinical study.

To evaluate the treatment effects of a variable degree of forward posturing of the mandible incorporated into the Bionator, a study was undertaken on 14 patients with Class II, Division 1 malocclusion, treated for 1 year with a Bionator, maintaining the mandible in an edge-to-edge incisal position (Be group). This group was compared with a matched group of patients treated with the Bionator in whom the mandible was maintained in a "functional maxipropulsion" (Bmax group). Both groups were subdivided further according to sex for selected parameters. Twenty-nine measurements on cephalometric x-ray films taken before and after 1 year of treatment were statistically analyzed. According to this study, "edge-to-edge" protrusion is superior to "functional maxipropulsion" in increasing ramal height. The difference in increase in corpus length after treatment (greater in boys than in girls) was sex related rather than dependent on appliance characteristics. When studying the effect of functional appliances, it is suggested that a patient group be subdivided by sex. After treatment a repositioning of the condyle was found in a more downward and possibly slightly forward direction relative to sella point (S) in both groups. A relocation of the condyle should be considered as another treatment effect of functional appliances. The more important lowering of the condyle found in the Bmax group may partly explain the significant increase in SNB, the 1.6-fold larger decrease in overbite, and the highly significant increase in anterior lower facial height in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study between the SFS and LFS rotation as a possible morphogenic mechanism.

Cephalometric tracings of twenty-seven untreated adult Caucasians, selected on a clinical impression of reduced lower facial height were studied and compared with tracings of nine untreated adult Caucasians with increased lower facial height. Various linear and angular measurements for both groups were analyzed and compared. As has been previously described for the SFS, the LFS group can be subdivided into at least two subtypes. Subtype I is characterized by a long ramus, increased OP-PP, an increased SN:MP-angle, and excessive lower anterior facial height. These persons manifest the most typical clinical characteristics of the long face syndrome and have excessively long faces. In Subtype II, however, extreme backward and downward rotation of the mandible, combined with a short or extremely short ramus, is associated with an increase in lower anterior facial height. The increase in posterior maxillary height was not striking in this subtype. It was demonstrated that many of the characteristics of the LFS group and the SFS group can be explained by clockwise or counterclockwise rotation of the mandible "in concert" with the hyoid, tongue, pharynx, and cervical spine. The LFS group was characterized by a clockwise rotation of the mandible "in concert" with the hyoid, tongue, pharynx, and cervical spine. The mandible of the SFS group rotated similarly, but in the opposite counterclockwise direction. The vital need to maintain patency of the upper airway at the level of the base of the tongue may account for rotation in the LFS.

The short face syndrome.

Cephalograms of twenty-seven untreated adult Caucasians, selected on the basis of a clinical impression of reduced lower facial height, were studied. Various linear and angular measurements were studied and compared to the Bolton standards. The short face syndrome SFS is a clinically recognizable facial type with reduced lower facial height as the common denominator. On the basis of the FPI (facial proportion index), the RH (ramus height), the OP-PP distance (or posterior maxillary height), and the SN:MP angle, two subgroups were distinguished in the SFS group. SFS, was characterized by a long ramus, sharply reduced SN:MP angle, an FPI close to 10, and a slightly reduced posterior maxillary height. In contrast, SFS2 was characterized by a short ramus, a slightly reduced SN:MP angle, an FPI with values around or below zero, and a sharply reduced posterior maxillary height. The latter group was designated as vertical maxillary deficiency.

[Leontiasis ossea: a symptom...!]. / Leontiasis ossea : un symptôme...!

The keyword "leontiasis ossea" has no diagnostic significance. It is only a description of a symptom of bone disease with a broad variability such as Paget's disease, fibrous dysplasia, hyperparathyroïdism and condensing osteopathies. (Pyle's disease, or cranio-diaphyseal dysplasia.) The first case presented shows advanced Paget's disease with radiographic signs of maxillary bone pathology. A tooth extraction in this patient was complicated by a severe healing problem. Sequestration occurred after two years. Healing was only obtained after removal of the sequestrum. The authors believe that the healing problem was directly related to Paget's disease of maxillary bone. The second case represents a patient with hyperparathyroïdism, showing an unusual facial swelling as only physical symptom of the disease. The problem of interpretation of biopsymaterial and the occurrence of osteosclerotic appearence on X-ray are discussed. The authors suggest that a complete examination (X-ray of the skeleton, blood and urine parameters, and functionel tests) should be performed to put forward a right diagnosis in the patient, presenting leontiasis ossea.