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PubMed1995

Case report: treatment of dental asymmetry.

The treatment of dental asymmetries often comprises several treatment alternatives. This case report describes the treatment alternatives for an asymmetry generated secondary to surgical removal of an odontoma that included the germ of the lower left lateral incisor. The opening of the space was chosen based on the patient's wish. The asymmetrical biomechanical force system used for the correction of the midline is presented as free-body diagram.

Adult↗
PubMed1997

Distal molar movement using the pendulum appliance. Part 2: The effects of maxillary molar root uprighting bends.

A clinical study was recently undertaken to evaluate the dental and skeletal effects of the pendulum appliance (PA). In the present study, the appliance was modified by incorporating an uprighting bend into the distalizing spring during the second phase of treatment to avoid excessive distal tipping of the maxillary molars. The sample consisted of 20 patients: 8 females and 12 males, mean age 13.11 +/- 1.10 years. Eight of the patients were subjected to a slow rate of maxillary expansion. Measurements were obtained from cephalometric headfilms prior to (T1) and the day of removal (T2) of the PA. Treatment changes were analyzed and compared with the previous study. The PA with uprighting bends led to reduced molar tipping without significantly changing the effects of the PA, with the exceptions of 0.62 mm more anchorage loss of the maxillary incisor edge and increased treatment time. There was no significant difference in anchorage loss between the patients with and without maxillary expansion.

Adolescent↗
PubMed2001

Transmigrant mandibular canines: a record of 28 cases and a retrospective review of the literature.

The transmigrant mandibular canine is a rare phenomenon. Most authors have described singular cases of unilateral or bilateral occurrence; however, a few authors have published more cases. This paper describes 28 cases exhibiting transmigratory canines. The observations are compared with observations from 39 earlier reports. Women are affected more than men. The left canine undergoes transmigration more commonly than does the right canine. Transmigration and impaction appear to be more common. Most of the patients do not have any symptoms, and these canines are often discovered at the radiological examination before orthodontic treatment. The etiology is obscure; however, abnormal displacement of the tooth bud in embryonic life is a commonly accepted explanation. Prolonged retention of the deciduous canine is a good clinical sign for a thorough radiological examination, preferably including an orthopantomographic radiograph. This would help in preventive measures. However, once established, a transmigrated canine requires surgical extraction. If possible, and if space is available and the patient is willing, all orthodontic efforts should be made to restore the normal position of this functionally very useful tooth in the human dentition.

Adolescent↗
PubMed2001

Cephalometric comparison of maxillary second molar extraction and nonextraction treatments in patients with Class II malocclusions.

This retrospective cephalometric study compared the nature of the skeletodental correction of maxillary second-molar extraction and nonextraction treatments in correcting Class II malocclusions. The sample comprised 50 Class II, deep-bite, low-angle adolescents; half were treated with maxillary second-molar extraction and half were treated without extraction. Pretreatment and posttreatment lateral cephalograms were analyzed. Analysis relied primarily on the method of Lysle Johnston that evaluates sagittal changes in the teeth and supporting bones relative to the functional occlusal plane. All 18 cephalometric variables examined were statistically equivalent between the 2 groups at the start of treatment. In contrast, several skeletodental treatment changes differed significantly. The maxillary second-molar extraction group exhibited distal movement of the maxillary first molar (1.2 mm vs 0.0 mm), and there was greater flaring of the mandibular incisors in the nonextraction group (9.1 degrees vs 3.5 degrees ). The upper incisor root was torqued lingually in both groups, but there was more anterior crown movement in the nonextraction group (2.0 mm vs 0.0 mm). Also, the extraction group finished active treatment 7 months sooner on average. Sagittal molar correction in the maxillary second-molar group was a result of distalizing in the maxillary arch, whereas anchorage was expended in the mandibular arch to correct the malocclusion in the nonextraction group. In properly selected Class II malocclusions, maxillary second-molar extraction is a viable alternative treatment choice.

Adolescent↗
PubMed2000

Analysis of lateral tooth movement during forced orthodontic eruption.

STATEMENT OF PROBLEM: Forced eruption is a prosthodontic procedure that enables the treatment of otherwise problematic restorative conditions. During the vertical orthodontic movement, the root may be moved laterally, affecting the position of a tooth in the arch. PURPOSE: This study quantified the degree of lateral movement possible during the eruptive procedure and addressed the significance of this movement from a theoretical and clinical standpoint. MATERIAL AND METHODS: A patient treatment, which demonstrated the movement in a single direction on the buccolingual axis, was isolated. On the basis of this theoretical model, a clinically relevant model was developed: A "worst-case" situation for each posterior tooth was calculated, from which clinical conclusions may be derived. RESULTS: . In a given extrusion angle of 30 degrees, a lateral movement/shift of 0.58 mm resulted per 1 mm of eruption distance. The lateral movement for every millimeter of eruption and the maximum extrusion angle for each of the maxillary and mandibular posterior teeth were calculated. CONCLUSION: The lateral movement that accompanies the forced eruption procedure may compromise or be used to esthetically enhance prosthodontic treatment.

Bicuspid↗
PubMedDate not supplied

Applications of surface-surface matching algorithms for determination of orthodontic tooth movements.

Orthodontic tooth movements are described as the differences between initial and final tooth positions. A computer based method for determination of tooth movements for different treatment methods was developed. A total of 20 casts of the upper jaw of patients treated with tooth positioners or fixed appliances were used as a basis for this study. Tooth movement was analysed on casts before (Ci) and after treatment (Cf). The casts were digitized either with a COMT or 3D laser scanning systems. After digitization, the models were superimposed in the palate by using a surface-surface matching algorithm. Tooth surfaces of the orthodontically moved teeth were segmented and determination of tooth movement was accomplished by matching the moved teeth from Ci to Cf. The resulting transformations delivered three dimensional information on translations and rotations. An accuracy of 0.2 mm in translations and 1 degree in rotations could be demonstrated, showing the different efficiency of treatment schemes.

Algorithms↗
PubMed1991

Tooth displacement analysed on human autopsy material by means of a strain gauge technique.

Tooth displacement was analysed on human autopsy material for various types of orthodontic force systems using an electronic strain gauge technique. Tooth movements were registered in two dimensions with low force clip gauges on three sections of the mandible, containing the first premolar and the first molar. The sensitivity was 0.1 microns when horizontal forces of 50, 100, and 150 cN were applied at different horizontal levels producing different M/F ratios. The relationship between a force system and the resulting tooth movement was described by the position of the centre of rotation, CR, and the angle of rotation. The centre of resistance was determined for the three autopsy specimens, and depended on tooth geometry, root length, and level of bony margin. Important differences in location were found. The dynamics of initial tooth movement were analysed within the first minute of load application. Force/displacement curves were generated to evaluate the behaviour of the periodontal ligament. There was a linear correlation between the two variables. Freezing the autopsy material some days before testing had no detectable effect. The results from measurements on human autopsy material were compared with previously derived in vivo measurements.

Adolescent↗
PubMed1996

Agenesis of mandibular second premolars. Spontaneous space closure after extraction therapy: a 4-year follow-up.

The aim of this study was to investigate the space closure and occlusal changes in 11 subjects (mean age 11.8 years) with normal occlusion and agenesis of the mandibular second premolar, after extraction of the mandibular secondary primary molar and the maxillary second premolar on the side of the agenesis. The treatment started when the first premolars came into occlusion and the subjects were followed for 4 years. Dental casts were taken at the start of treatment and after 1, 2 and 4 years, and lateral cephalograms were taken at the start of treatment and after 2 and 4 years. Space closure, sagittal movements, rotational movements, and tipping of the first molars and first premolars and dental midline shift were measured on photographs of dental casts. Sagittal movement of the incisors was measured on lateral cephalograms. The results showed that most of the extraction space closed during the first year (55 per cent in the maxilla, 46 per cent in the mandible) and at the end of the follow-up period 89 per cent of the extraction space closed in the maxilla and 80 per cent in the mandible, leaving a mean residual extraction space of 0.9 and 2 mm respectively. In the maxilla, 70 per cent of the extraction space closed by mesial and rotational movements of the first molars. Maxillary premolars moved distally, rotated and tipped only during the first year of observation. In the mandible, the space closure occurred by mesial/rotational movements and tipping of first molars and distal movement and tipping of the first premolars. Unilateral extraction had no influence on the maxillary midline while it caused a statistically significant mandibular dental shift to the extraction side. Extraction therapy had no impact on the overjet, overbite or incisor inclination.

Adolescent↗
PubMed2001

Mesio-marginal findings at tilted molars. A histological-histomorphometric study.

The aim of this study was to investigate the mesio-marginal findings at tilted molars (TM) by means of histological-histomorphometric evaluation. Eight lateral tooth bone segments with TM (six mandibular, two maxillary) from males aged 20-32 years were compared with those of eight samples with non-tilted molars (NTM) in males aged 18-35 years. In comparison with the NTM samples, the TM revealed a higher amount of supra- and subgingival plaque, a significantly higher total number of inflammatory cells (P < 0.05) and blood vessels (P < 0.05) in the connective tissue adjacent to the junctional epithelium, and a lower density and corono-apical width of gingival fibres. No significant differences (P > 0.05) were found between the mesio-marginal bone level of the TM (mean: 978 microns) and that of the NTM (mean: 1222 microns). In contrast, indications were found that TM may affect the disto-marginal bone level of the mesial tooth.

Adolescent↗
PubMed2006

Effects of a segmented removable appliance in molar distalization.

The aim of the present investigation was to evaluate the skeletal and dentoalveolar treatment effects of a segmented removable appliance [removable molar distalizer (RMD)] for molar distalization. The study was conducted on 28 patients (12 females and 16 males), with a mean age of 11.8 years. All presented with a skeletal Class I malocclusion and a bilateral dental Class II molar relationship. The pre- and post-distalization records included lateral head films, study models and standard photographs. The findings were evaluated with a paired samples t-test. The average maxillary first molar distalization with the RMD was 3.98 mm, with 4.61 degrees of distal tipping. The maxillary second premolars drifted distally 2.13 mm on average with 1.54 degrees of distal tipping, while the maxillary first premolars showed 1.23 mm of mesial movement and 1.98 degrees of mesial tipping. The incisors protruded 1.09 mm with 1.27 degrees of labial tipping. The RMD was effective in distal molar movement and all patients attained a bilateral Class I molar relationship in an average period of 4.5 months. Hygiene problems and mucosal irritations, frequently found with fixed intraoral distalization techniques, were not observed during the distalization period.

Cephalometry↗
PubMed2002

A randomized clinical trial to compare the effectiveness of canine lacebacks with reference to canine tip.

AIM: To assess the effectiveness of canine lacebacks on the proclination of the upper incisors with reference to pre-treatment canine tip. STUDY DESIGN: Randomized clinical trial. SAMPLE: Patients receiving upper and lower fixed appliances attending the orthodontic departments of five orthodontic treatment providers. Sixteen patients received canine lacebacks as part of their treatment and 19 patients did not have canine lacebacks. METHOD: Patients were randomly allocated to receive canine lacebacks or not receive canine lacebacks. Upper study models were collected at the initial archwire placement and then when the working 0.019 x 0.025-inch stainless steel archwire was placed. The start canine angulation, change in upper incisor proclination/overjet, and any mesial movement of the upper first permanent molars during levelling and aligning was measured with a reflex metrograph. STATISTICS: The effect of the use of canine lacebacks on upper incisor proclination and mesial molar movement was assessed using Student t-tests. Regression analysis was used to evaluate any effect of the initial angulation of the canine. RESULTS: A mean incisor retroclination of 0.5 mm was observed in the canine lacebacks compared with a mean proclination of 0.36 mm when canine lacebacks were not used (P = 0.025). There was no statistically significant difference between groups for mesial movement of upper first molars (P = 0.99). If the canine was more distally inclined at the start of treatment, the incisors was more likely to procline, regardless of whether or not canine lacebacks were used (P = 0.027). CONCLUSIONS: The effect of canine lacebacks on preventing upper incisor proclination at the start of treatment is in the order of 1 mm and their effect on mesial molar movement is insignificant. Canines lacebacks have similar effects that are independent of pre-treatment canine angulation.

Adolescent↗
PubMed1983

The use of cranial bone grafts in the closure of alveolar and anterior palatal clefts.

A method is described for harvesting cancellous bone from the diploic space. In our opinion, this is the material of choice for bone grafting alveolar clefts in the 7- to 11-year age group. The procedure could be performed at an earlier age if the maxillary segments are under orthopedic control and in proper alignment. Success of the procedure depends on proper orthodontic preparation of the maxillary segments and careful, complete closure of the soft tissues across the anterior palatal cleft, the nasal lining defect, and the anterior alveolus. Results have been encouraging in terms of bone formation, and tooth migration into the bone graft can be expected if there has been no damage to the dental sac. Closure of the alveolar defect at the time of the primary lip closure would preclude the eventual need for a bone graft, but it cannot be accomplished without early, precise alignment of the maxillary segments if extensive periosteal denudation is to be avoided. The age beyond which periosteal closure alone will be inadequate to provide sufficient bone formation and should be supplemented by a bone graft remains to be established.

Adolescent↗
PubMedDate not supplied

Root intrusion in tooth-implant combination cases.

The various proposed etiologies for root intrusion in tooth-implant combination cases are discussed. Clinical examples of root intrusion are illustrated. Advantages and disadvantages of nonrigid connector and coping/suprastructure techniques are presented.

Dental Abutments↗
PubMed2004

Reconstruction of the maxillary midline papilla following a combined orthodontic-periodontic treatment in adult periodontal patients.

OBJECTIVE: The aim of the present study was to evaluate the role of a combined orthodontic-periodontic treatment in determining the reconstruction of midline papilla lost following periodontitis. MATERIAL AND METHODS: Twenty-eight patients, with infrabony defect and extrusion of one maxillary central incisor, were treated. At baseline, all patients presented opening of the interdental diastema and loss of the papilla. At 7-10 days after open-flap surgery, the intrusive movement started. For each patient, probing pocket depth (PPD), clinical attachment level (CAL) and papilla presence index (PI) were assessed at baseline, end of treatment and after 1 year. PI was also evaluated independently in patients with narrow or wide periodontal biotype (NPB-WPB). RESULTS: All parameters showed statistical improvement between the initial and final measurements, and showed no changes at follow-up time. The mean residual PPD was 2.50 mm, with a decrease of 4.29 mm, while the mean CAL gain was 5.93 mm. Twenty-three out of 28 patients improved the PI score at the end of therapy. No statistical difference was recorded in PI values between groups NPB and WPB. CONCLUSION: The presented clinical protocol resulted in the improvement of all parameters examined. At the end of orthodontic treatment, a predictable reconstruction of the interdental papilla was reported, both in patients with thin or wide gingiva.

Adult↗
PubMed1993

Balancing the extraction of primary teeth: a review.

Balancing the extraction of primary teeth is a procedure advocated to maintain symmetry of the developing dentition by encouraging symmetrical drift of teeth mesial and distal to the extraction sites on each side of the dental arch. Current opinion about this procedure expressed in standard reference works is confused and occasionally contradictory. Whilst some authorities cite specific situations where balancing extractions should be performed, others are less precise with their advice, and at least one considers that there is little justification for the procedure. Scientific evidence supporting the procedure is tenuous. The one study carried out specifically to compare dental centre line shift following unilateral or bilateral extraction of primary teeth showed greater shift in cases of unilateral (unbalanced) extractions. Other studies do not directly address the issue and such information as they offer is imprecise. Although the procedure of balancing extractions is strongly advocated by many clinicians, it is not based on definitive experimental evidence.

Child↗
PubMed1994

Extraction of primary canine tooth buds: prevalence and associated dental abnormalities in a group of Ethiopian Jewish children.

Recent publications have described a common belief, held in rural areas in Africa, that unerupted primary canines cause diarrhoea, vomiting and fever in infants. To relieve these symptoms a traditional native healer extracts these tooth buds. The emigration of Ethiopian Jews to Israel in 1991 allowed an investigation of this practice among this community. A group of 59 children (27 boys and 32 girls) aged 3-12 years were examined clinically and radiographically. Evidence was found of extraction of 63 primary canine buds in 35 (59%) of the children. Extraction of one canine was found in 16 children, two in 13 children and three in three children, and three children had all four canines extracted. Forty-six (74%) mandibular compared to only 16 (26%) maxillary canines had been extracted; the extractions were equally divided between both sides of the jaws. Another 19 primary canines had hypoplastic defects, probably the result of unsuccessful extractions. Associated dental abnormalities included hypoplasia of the permanent successors and adjacent primary and permanent teeth, displacement of permanent teeth, midline shift to the extraction side, missing primary lateral incisors (probably accidentally extracted) and distal eruption of permanent lateral incisors, leaving their primary predecessors retained. Parental enquiry revealed that the practice is more common in rural rather than urban areas and still exists in the Ethiopian community in Israel. The findings of this survey should urge the authorities to take steps to stop this practice.

Child↗