Mandibular bone graft material for reconstruction of alveolar cleft defects: long-term results.

OBJECTIVE: To analyze the long-term effect of mandibular bone as donor material in bone grafting of the alveolar process defect in patients with unilateral cleft lip and palate (UCLP), compared with iliac crest cancellous bone. METHOD: During a 7-year period, 101 UCLP patients were bone grafted, 57 cases with iliac crest cancellous bone and 44 with mandibular symphyseal bone. The long-term results with an observation time of more than 4 years were analyzed with respect to marginal bone level and dental and gingival condition in the grafted area. Complications were recorded. RESULTS: The bone level in the grafted area was satisfactory in both groups. Impaction of cleft-side canines was found in 35% of the patients in both groups. Patients with agenesis of the cleft side lateral incisor had significantly more impacted canines, compared with patients with a cleft-side lateral situated in the lesser maxillary segment, probably due to the fact that the lateral incisors help in guiding the canine down through the grafted area. The number of complications was scarce, although both groups demonstrated some gingival retraction with a longer crown length at the cleft side central incisor. CONCLUSION: The findings of this study have changed our strategy in bone grafting. Timing of orthodontic treatment and bone grafting has been more varied depending on the position and presence of teeth in the cleft area. Bone grafting of the alveolar process is not just a local treatment of a bony defect, but in respect to the burden of treatment, bone grafting of the alveolar process has to be planned in accordance with orthodontic treatment and maxillofacial growth.     

Radiographic determination of the position of the maxillary lateral incisor in the cleft alveolus and parameters for assessing its habilitation prospects.

OBJECTIVE: Develop patient selection criteria and guidelines for the diagnostic work-up for early secondary alveolar bone graft designed to accommodate a lateral incisor in the cleft. DESIGN: A literature review with clinical examples. INTERVENTIONS: For the majority of cleft lip and palate (CLP) patients, the timing of the secondary alveolar bone graft procedure is devised to accommodate the eruption of the maxillary canine. However, when the lateral incisor is present in the cleft area, a decision may be made to perform early grafting in order to salvage an additional tooth. Appropriate case selection for this intervention is the key for successful dental habilitation in the cleft area. RESULTS AND CONCLUSIONS: Attempts to maintain the lateral incisor are recommended only if the tooth contributes to the comprehensive orthodontic and restorative patient care and when the presence of a lateral incisor with adequate size, shape, and proper position may be demonstrated. For optimal decision making, the position, form, and periodontal ligament support of the lateral incisor should be assessed. Evaluation of these parameters is based chiefly on radiographic imaging. Occlusal projections and traditional tomography may augment the information available from periapical and panoramic radiographs. However, each of these has benefits and drawbacks that require consideration.     

Maxillary canine impactions related to impacted central incisors: two case reports

AIM: The purpose of this case report is to describe the combined surgical and orthodontic treatment of two cases with an impacted maxillary central incisor and canine in the same quadrant and to discuss the causal relationship between them. BACKGROUND: The most common causes of canine impactions are usually the result of one or more factors such as a long path of eruption, tooth size-arch length discrepancies, abnormal position of the tooth bud, prolonged retention or early loss of the deciduous canine, trauma, the presence of an alveolar cleft, ankylosis, cystic or neoplastic formation, dilaceration of the root, supernumerary teeth, and odontomas. Although impaction of the maxillary central incisor is almost as prevalent as impacted canines its etiology is different. The principal factors involved in causing the anomaly are supernumerary teeth, odontomas, and trauma. REPORTS: Case #1: A 10.5-year-old girl in the early mixed dentition stage presented with a chief complaint of the appearance of her anterior teeth. She had a Class I skeletal pattern and a history of trauma to the maxillary central incisors at age five with premature exfoliation. Radiographs revealed an impacted upper right central incisor in the region of the nasal floor, delayed eruption of the maxillary permanent central incisor, and the adjacent lateral incisor was inclined toward the edentulous space. Treatment was done in two stages consisting of surgical exposure and traction of the impacted central incisor and fixed orthodontic treatment. Case #2: An 11.5-year-old girl presented for orthodontic treatment with the chief complaint of an unerupted tooth and the appearance of her upper anterior teeth. She was in the late mixed dentition period with a Class III skeletal pattern along with an anterior cross-bite with some maxillary transverse deficiency. The maxillary right canine and central incisor were absent, but the maxillary right deciduous canine was still present. Treatment included arch expansion followed by surgical exposure and traction of the impacted teeth and fixed orthodontic treatment. SUMMARY: This case report provides some evidence of a significant environmental influence of an impacted maxillary central incisor on the path of eruption of the ipsilateral maxillary canine. When an impacted maxillary central incisor exists, the maxillary lateral incisor's root might be positioned distally into the path of eruption of the maxillary canine preventing its normal eruption. Ongoing assessment and early intervention might help to prevent such adverse situations from occurring.     

Special distraction osteogenesis before bone grafting for alveolar cleft defects to correct maxillary deformities in patients with bilateral cleft lips and palates: Distraction osteogenesis performed separately for each bone segment

IntroductionPatients with bilateral cleft lips and palates have premaxillary protrusion and characteristic jaw deformities involving three-dimensional malposition of the premaxilla and bilateral maxillary bone segments. This study examined patients with bilateral cleft lips and palates who had deviation and hypoplasia of the premaxillas and bilateral maxillary segments. Before bone grafting, the patients were treated with special distraction performed separately for each bone segment using a halo-type external device. This report describes this novel treatment method which produced good results.Material and methodsThe subjects were five patients with severe jaw deformities due to bilateral cleft lip and palate. They were treated with maxillary Le Fort I osteotomy and subsequent distraction performed separately for each bone segment using a halo device. In three of five patients, premaxillary osteotomy was not performed, and osteotomy and distraction were performed only for the right and left lateral segments with severe hypoplasia.ResultsAll patients achieved distraction close to the desired amount. The widths of the alveolar clefts were narrowed, and satisfactory occlusion and maxillary arch form were achieved. After the surgery, three of five patients underwent bone grafting for bilateral alveolar cleft defects and the bone graft survival was satisfactory.ConclusionsThis method had many benefits, including narrowing of alveolar clefts, improvement of maxillary hypoplasia, and achievement of a good maxillary arch form. In addition, subsequent bone grafting for alveolar cleft defects was beneficial, dental prostheses were unnecessary, and frequency of surgery and surgical invasiveness were reduced. This method is a good surgical procedure that should be considered for patients with bilateral cleft lips and palates who have premaxillary protrusion and hypoplasia of the right and left lateral segments.     

Modified VIP-CT flap in late maxillary alveolar cleft surgery

ObjectiveThis article describes a new application for the modified vascularized interpositional periosteal-connective tissue flap (modified VIP-CT flap) to solve problematic cases of late maxillary alveolar cleft bone grafting.MethodsThis study analysed the ability of the VIP-CT flap to provide coverage of bone grafts in maxillary alveolar cleft surgery. Donor site morbidity was also evaluated.ResultsThirteen patients were operated on using this technique, seven patients were female, the age range was between 12 and 25 years, and all of them were missing at least one permanent anterior tooth adjacent to the cleft. Two patients had bilateral alveolar clefts. In most of the operated patients one VIP-CT flap was used, but in two patients (cases 3 and 4) bilateral VIP-CT flaps were used for treatment of wide alveolar clefts. In case 3 both of the flaps were used for closure of the oral side and in case 4 one flap was used for nasal closure and another for oral side coverage. Two patients had alveolar cleft only with normal palatal anatomy, and the remaining patients had previously operated cleft palates (11 patients).ConclusionVIP-CT flaps can readily be used in adult patients with cleft lip (alveolar only) and in many operated unilateral and bilateral complete cleft lip and palate patients successfully.     

Prediction of maxillary canine impaction using eruption pathway and angular measurement on panoramic radiographs

ObjectivesTo compare the normal eruption pattern and angulation in impacted maxillary canines using panoramic radiographs to predict maxillary canine impaction.Materials and MethodsPatients aged 6 to 15 years were classified into the normal eruption group (n = 229) and the impaction group (n = 191). At least two panoramic radiographs were taken in the normal eruption group during the eruption process of the maxillary canine. The growth pattern of the maxillary canine was analyzed using an XY coordinate system, with the tip of the maxillary lateral incisor as the origin and the tooth''s long axis as the Y-axis and measurement of the relative position of the crown tip and angulation of the maxillary canine.ResultsThe crown tips of normally erupted maxillary canines were intensively distributed along the distal surface of the maxillary lateral incisor, while those of impacted canines were widely distributed. The angulations of the normally erupted canines increased as eruption increased along the lateral incisor and then decreased at the cervical point of the lateral incisor. The angulations of the impacted canines were scattered, with no uniform pattern.ConclusionsWhile using the normal eruption path of the maxillary canine and the pattern of change in angulation based on the distal surface of the maxillary lateral incisor, early intervention or regular follow-up is needed to prevent maxillary canine impaction.     

Evaluation of alveolar bone support of the permanent canine in cleft and noncleft patients.

OBJECTIVE: To quantitatively compare the alveolar bone support ratio of the permanent canine in cleft patients who received secondary alveolar bone graft with that of the population without clefts. DESIGN: Retrospective study utilizing periapical radiographs of the subjects with and without clefts. SETTING: Hospital and university based. PATIENTS: Eighteen unilateral and 9 bilateral cleft patients who had secondary bone graft procedures. MAIN OUTCOME MEASURES: Alveolar bone support of the permanent canine utilizing the ratio of bone height to root length. RESULTS: Average bone support for the permanent canine was 88.55% in patients with clefts and 95.59% in patients with no history of clefts. This difference was statistically significant. There was no statistically significant difference in alveolar bone support ratio between the unilateral and bilateral cleft patients. CONCLUSIONS: Although alveolar bone support was significantly higher in the noncleft control group, a successful level of alveolar bone support was achieved for the permanent canine on the cleft site after secondary bone graft. There was no difference in alveolar bone support achieved for the permanent canine whether the type of the cleft was unilateral or bilateral.     

Evaluation of bone volume following bone grafting in patients with unilateral clefts of lip, alveolus and palate using a CT-guided three-dimensional navigation system.

PURPOSE: In cleft patients the eruption of the permanent canine depends very much on the amount of bone available following bone grafting. The purpose of this study was to evaluate the initial defect in alveolar clefts and the volume of bone bridging found in unilateral clefts which had undergone bone grafting. PATIENTS AND METHODS: To determine the fate of the bone graft in cleft palate patients a three-dimensional CT-based Navigation System (Zeiss, Aalen, Germany) was used. CT scans of 16 patients with unilateral clefts were taken immediately preoperatively and 1 year postoperatively. The patients underwent surgery between the age of 9 and 14 years using iliac crest bone grafts. The data was transferred to the work station of the navigation system. Using the STN software, the defect at the alveolar clefts and volume of the bone grafts were determined in each case. Three-dimensional models were created showing the amount of bone immediately preoperatively and 1 year postoperatively. RESULTS: The size of the cleft defect did not correlate with the success rate of the alveolar bone grafting. The form of the transplant remained almost constant when the permanent canine erupted spontaneously into the graft. In cases of absence of the permanent tooth or when the permanent canine required orthodontic treatment, significant bone loss could be observed in the buccopalatal direction. CONCLUSION: Three-dimensional reconstruction of bone grafts using a navigation system enables a valuable objective assessment of graft volume. Bone formation can be assessed in all three dimensions showing a high grade of resorption in patients lacking physiological load.     

Maxillary incisor impaction and its relationship to canine displacement.

This study aimed to examine the eruption status of unerupted maxillary permanent canines in patients who also had an impacted central incisor. Seventy-five unilateral cases of the incisor anomaly were retrospectively examined. Using the initial panoramic films, we assessed the positions of the ipsilateral and contralateral canines and the lateral incisors and the timing (eruption progress) of the canines. The final position of the canines was evaluated from patient records and progress photographs. The data showed a significant increase in prevalence and severity of displaced canines in the ipsilateral side (41.3%) compared with the contralateral side (4.7%). Palatally displaced canines occurred in 9.5%, buccally displaced canines in 30.2%, and canine-lateral incisor transposition in 1.6% of the patients. Half of the buccally displaced canines in the ipsilateral side were pseudotransposed with the adjacent lateral incisor. The eruption timing of ipsilateral undisplaced canines was either similar or delayed, relative to the contralateral tooth, but never accelerated. The ipsilateral lateral incisor was strongly angulated because of a more distally located apex (5 mm) rather than a mesially tipped crown. The ipsilateral canine was relatively more superiorly positioned (undererupted). Patients who had trauma had a significantly higher prevalence and severity of canine displacement and more distally displaced lateral incisor apices. Initial height of incisor impaction did not influence the results. These data provide evidence of a significant environmental influence of an impacted maxillary central incisor in delaying and altering the eruption path of the ipsilateral maxillary canine.     

Allogeneic bone for secondary alveolar cleft osteoplasty

The purpose of this retrospective clinical study was to determine the efficacy of allogeneic bone for secondary alveolar cleft osteoplasty. Twenty-four patients with unilateral cleft lip and palate treated with allogeneic bone grafts were examined by a surgeon, orthodontist, and prosthodontist 20 to 47 months after surgery. Radiographic and clinical examination of the periodontal status of the teeth adjacent to the cleft and their antimeres were compared for differences with Student's t test and the Wilcoxon test. Radiographs indicated complete bone bridging in 21 patients. Two of the remaining three patients had a 1-mm radiolucent gap in the cleft site. The third patient had a 6-mm-wide radiolucency and recurrence of an oronasal fistula which was regrafted with autogenous bone. No statistically significant differences between the cleft and noncleft tooth antimeres were found for plaque, gingivitis, bleeding, sulcus depth, or level of attachment. A statistically significant difference in the amount of attached gingiva was found between the cleft and noncleft tooth antimeres. Nine patients with missing lateral incisor teeth avoided prosthetic replacement by orthodontic movement of the canine tooth into the grafted edentulous space. In those cases where the maxillary canine was unerupted at the time of the surgery, eruption into the graft occurred. Stability of the maxillary segments was sufficient to allow prosthodontic restoration with a fixed partial denture in those cases where it was indicated.     

单侧上颌尖牙阻生对牙颌三维结构的影响

目的: 采用锥形束CT（CBCT）研究单侧尖牙阻生病例牙颌的三维结构特征,评估发生上颌尖牙阻生的相关风险因素,为正畸临床早期干预提供依据。方法: 选取30例单侧上颌尖牙阻生患者的CBCT,利用Romexis软件进行三维重建,测量、比较两侧牙颌三维结构特征指标,采用SPSS17.0软件包进行配对t检验和相关数据的回归分析。结果: 阻生侧尖牙和侧切牙倾斜度明显增大,尖牙牙冠更向近中、侧切牙向远中倾斜（P<0.001）;阻生侧尖牙体积更大、侧切牙体积更小（P<0.05）,当尖牙体积增大或侧切牙体积减小时,上颌尖牙的阻生概率增加;阻生侧牙弓弧形长度更短,牙弓宽度在尖牙区和前磨牙区更短（P<0.001）,而宽度在磨牙区无显著差异（P>0.05）,两侧牙弓长度在尖牙区、前磨牙区和磨牙区无显著差异（P>0.05）。结论: 上颌尖牙阻生伴随或导致同侧牙及牙槽骨三维方向发育异常,上颌尖牙阻生的严重程度与周围牙颌结构异常密切相关,提示上颌尖牙阻生可以早期预判、诊断,且可以实施有效的早期干预。     

The prevalence of various dental characteristics in the primary and mixed dentition in patients born with non-syndromic unilateral cleft lip with or without cleft palate

This retrospective study was carried out on consecutively collected dental casts, x-rays, and photos of 129 Swedish children who had been born with non-syndromic unilateral (U) cleft lip (CL), cleft lip and alveolus (CLA), or cleft lip and palate (CLP). The following dental characteristics were investigated in the primary and permanent dentitions: 1. the presence, eruption, position, and shape of the lateral incisor; 2. the prevalence of rotation and enamel hypoplasia of the permanent central incisor; 3. the occurrence of hypodontia outside the cleft region; and 4. the transition from the primary to the succeeding permanent lateral incisor in the cleft region. Patients with clefts involving the palate (UCLP) exhibited a high frequency of hypodontia. In patients with clefts, which did not include the palate, malformed lateral incisors were a common finding. In the primary and permanent dentition, the lateral incisor had erupted distal to the cleft in 31.8 and 24.8 per cent of the UCLA and UCLP patients, respectively. No significant pattern was seen regarding the transition from the primary to the succeeding permanent lateral incisor (P = 0.15). The central incisor was rotated in 55 per cent of the patients and this positional deviation was particularly frequent in cases where the lateral incisor was missing in the premaxilla (P < 0.05). Hypodontia outside the cleft region was recorded in 15.5 per cent of the patients. Patients with UCLP had more often crossbite than patients with a UCL or a UCLA phenotype (P < 0.001).     

Prospective analysis of secondary alveolar bone grafting using computed tomography.

PURPOSE: This study radiographically evaluated the quantity and quality of secondary alveolar bone grafts from the anterior iliac crest to maxillary alveolar clefts in cleft lip and palate patients with the use of computed tomography. PATIENTS AND METHODS: A 1-year prospective study was conducted by using 14 unilateral and bilateral cleft lip and palate patients. Axial and coronal computed tomography (CT) scans were obtained during the immediate postoperative phase and at 1-year follow-up. RESULTS: This study showed that the average alveolar cleft requires a bone graft volume ranging from 0.9 to 3.6 cm3, with a mean volume of 2.10 cm3. The percentage of bone loss derived from the linear dimensional changes to the alveolar bone graft between the immediate postoperative and follow-up CT scans were as follows: 17.9% in maximal bone height, 29.9% in maximal anteroposterior bone width, and 13.7% in maximal transverse width. As compared with the linear measurements, the volumetric analysis showed a disproportional amount of volume loss equaling 43.7% and 42.5% in the coronal and axial studies, respectively. This showed a total average volume loss of 43.1% at approximately 1 year after the secondary alveolar cleft repair. However, as the canine tooth erupts through the bone graft, it can account for up to 53.4% of the total average volume loss. All 14 patients (17 clefts) showed bone bridging between the alveolar cleft radiographically, with good incorporation and maturation of the bone graft, and no recurrence of the oronasal fistula. CONCLUSION: The CT scan is a valuable radiographic imaging modality to assess and follow the clinical outcome of secondary alveolar bone grafting.     

Canines erupted through grafted alveolar cleft defects in patients with alveolar clefts: a pulp testing evaluation study

An electric pulp tester (EPT) was used to evaluate the pulpal response of erupted canines in 75 patients: 16 patients with unilateral cleft palate who received autogenous bone grafts to correct their alveolar cleft defects before canine eruption; 35 patients without cleft palate whose canines erupted spontaneously, but who required orthodontic treatment for alignment; and 24 patients without clefts whose canines required surgical uncovering and orthodontic assistance for eruption. Thirty-one percent of the erupted canines in the patients with grafted unilateral clefts did not respond to EPT, whereas all canines in the contralateral noncleft side responded to EPT. There was no clinical or radiographic evidence of pulpal pathosis of the canines that had erupted through the grafted alveolar clefts. However, these teeth had a high incidence of nonresponsiveness to pulp stimulation, therefore necessitating close follow-up in case they show eventual signs of pulpal degeneration that may require endodontic intervention.     

Factors influencing secondary alveolar bone grafting in cleft lip and palate patients: prospective analysis using CT image analyzer.

OBJECTIVE: To examine the effect of migration of the germ of the lateral incisor into the bone for eruption factors on bone bridge resorption. METHODS: Twenty-five subjects who underwent secondary alveolar bone graft were enrolled. The volume of the alveolar bone grafts immediately after the operation (V1), bone bridge formation 6 months postoperatively (V2), and tooth (teeth) migration into the bone bridge (Vt) were measured using a computed tomography (CT) image analyzer. Based upon these measurements, the following points were examined: (1) the correlation between the tooth-occupied ratio (Rt = Vt/V2 x 100) and the ratio of bone bridge resorption (Rv = (V1 - V2)/ V1 x 100); and (2) comparison of the tooth-occupied ratio (Rt) and the ratio of bone bridge resorption (Rv) between the groups with and without the germ of the lateral incisor. RESULTS: A significant negative correlation was found between Rv and Rt (p < .001). Comparison of Rv and Rt between the groups with and without a germ of the lateral incisor revealed that both indices were significantly higher in the former group than the latter one (p < .05). CONCLUSION: In cleft lip and palate patients with a germ of the lateral incisor, it is beneficial to carry out secondary bone grafting to the alveolar cleft at the age of 5 to 7 years, preceding eruption of the canine, in order to form a good bone bridge that will facilitate eruption of the lateral incisor and subsequent normal dentition and occlusion.     

Maxillary growth in patients with clefts following secondary alveolar bone grafting.

OBJECTIVE: This investigation evaluated the effects of secondary alveolar bone grafting on subsequent maxillary growth in cleft patients. DESIGN: This was a retrospective longitudinal cephalometric study. Nineteen patients who had received secondary alveolar bone grafts were matched to a control sample by sex, cleft, availability of longitudinal records, and presurgical cranial base dimensions and growth direction. All patients had at least two lateral cephalometric radiographs before surgery and two radiographs after surgery. SETTING: The records were obtained from the Longitudinal Growth Study of the Lancaster (Pennsylvania) Cleft Palate Clinic. INTERVENTIONS: All patients had received similar primary surgical procedures by the same surgeon, no orthopedics, and similar mixed-dentition orthodontics. Secondary alveolar bone grafting was the only surgical intervention different between the two groups. MAIN OUTCOME MEASURES: Six measures of maxillary sagittal and vertical growth were taken from 235 radiographs. Slopes of the regression lines for each growth dimension were compared between groups both pre- and postsurgically. RESULTS: There were no significant between-group differences in maxillary sagittal or vertical growth following the grafting procedure. Anterior maxillary vertical growth rates decreased in the grafted group when their pre- and postsurgical rates were compared. Several growth trends in the postsurgical period were found to be continuations of the rates documented presurgically and unrelated to the grafting procedure. CONCLUSIONS: When evaluated longitudinally, maxillary growth in patients having received secondary alveolar bone grafting did not differ from a group of matched controls.     

The stability of Le Fort I maxillary osteotomies in patients with simultaneous alveolar cleft bone grafts

A retrospective study was performed on 20 patients who had been treated with Le Fort I maxillary osteotomies and simultaneous alveolar cleft bone grafts. The age range was 11 to 23 years, and there were 11 males and nine females. Changes in both anterior-posterior (A-P) and vertical direction were investigated using preoperative, immediate postoperative, and long-term postoperative lateral cephalometric radiographs. The results indicated little change between the immediate postoperative and long-term postoperative position of the maxilla in an A-P dimension, but in a vertical direction there was a great tendency for relapse.     

Comparison between combined cortical and cancellous bone graft and cancellous bone graft in alveolar cleft: Retrospective study of complications during the first six months post-surgery

BackgroundIn patients with alveolar cleft, alveolar bone graft is usually performed before the permanent maxillary canine or incisor eruption and using cancellous bone harvested from the iliac crest. The authors sought to compare the early complication rate in patients who received cancellous bone graft alone and cortical bone graft in addition to cancellous bone to reconstruct the nasal floor.MethodsFor this observational, retrospective, monocentric study, patients with alveolar cleft who underwent autologous alveolar bone graft and gingivoperiosteoplasty at Montpellier Hospital were divided into two groups: group A, who had cortical and cancellous bone graft; and group B, who had only cancellous bone graft. Both groups were followed for 6 months after surgery, and complications were recorded.ResultsIn total, 319 grafts (group A, 163; group, 156) were performed from June 1999 to May 2016. The major complication rates were 8% and 5.8% in group A and B, respectively, and were not significantly different (p = 0.52). Similarly, the rates of minor complications and of donor site morbidity were not different between groups.ConclusionsThis preliminary study shows that adding a cortical bone graft for the nasal floor reconstruction does not increase the risk of complications in 6 months following the graft. Long-term benefits such as alveolar height and a piriform aperture symmetrisation will have to be analysed to study the contribution of the technique.     

Alveolar bone grafting in patients with complete clefts: a comparative study between secondary and tertiary bone grafting.

OBJECTIVE: This investigation evaluated the results of alveolar bone grafting in patients with complete clefts, comparing secondary alveolar bone grafting (during the mixed stage of dentition) versus tertiary bone grafting (after completion of the second stage of dentition). DESIGN: This was a retrospective study. Of 140 osteoplasties, which all were operated according to the same standardized surgical technique, a clinical and roentgenological follow-up investigation was carried out in a collective of 85 osteoplasties. Clinically we searched for oronasal fistulae, assessed the periodontal status, determined the extent of the gingival attachment in the area of the osteoplasty, and searched for vertical growth disturbances in the area of the osteoplasty. Roentgenologically the height of the alveolar bone in the former clefted area was ascertained. SETTING: Records were obtained from a clinical and radiological study of the Department of Oral and Maxillofacial Surgery of the Medical University of Hannover (Germany). INTERVENTIONS: All patients were operated with the same standardized surgical method. The osteoplastic bridging of the alveolar cleft was performed via a vestibular gingival marginal incision and exclusively by grafting of cancellous bone from the iliac crest. RESULTS: The best results of alveolar bone grafting in cases of secondary osteoplasty were obtained when the lateral incisor or canine had grown into the transplant and had led to a functional stress of the transplanted bone. Approximately good results were to be found in tertiary osteoplasty when the transplanted bone had been stressed functionally through a dental implant. Comparing the secondary with the tertiary osteoplasty, there was a trend of lower resorption in secondary osteoplasty. CONCLUSIONS: Secondary osteoplasty should represent an integral component of any concept for the comprehensive treatment of patients with cleft lip and palate.     

青少年患者前牙内收过程中牙槽骨改建情况的锥形束CT研究

目的 通过锥形束CT（CBCT）研究双颌前突的青少年患者前牙内收过程中前牙区牙槽骨改建情况及特点。方法 选取无正畸治疗史双颌前突并且拔除4颗第一前磨牙的青少年患者30例（男12例,女18例,年龄12~18岁）,分别在内收前后1个月拍摄CBCT,测量上下颌每一颗前牙牙根颈1/3、中1/3、尖1/3处唇舌侧牙槽骨厚度,以及上中切牙切缘、牙根颈1/3、中1/3、尖1/3矢状向上内收前后移动的距离,利用SPSS 16.0软件对测量数据进行统计分析。结果 青少年患者上下颌前牙区牙槽骨在前牙内收过程中总体表现为唇侧牙槽骨厚度增加,舌侧牙槽骨厚度减少。其中上颌中切牙根颈1/3及中1/3、上颌侧切牙根颈1/3及尖1/3、下颌中切牙根中1/3、下颌侧切牙根尖1/3、下颌尖牙根中1/3及尖1/3在内收后其牙槽骨厚度表现为增加;上颌尖牙尖1/3、下颌尖牙颈1/3在内收后其牙槽骨厚度表现为减少;其余位点牙槽骨厚度表现为不变。结论 青少年患者前牙内收过程中,前牙发生受控制的倾斜移动,内收后,前牙区牙槽骨总体表现为唇侧牙槽骨厚度增加,舌侧牙槽骨厚度减少。前牙内收后多数位点表现为随牙齿移动牙槽骨厚度增加。