Three-dimensional morphology of the palate in subjects with unilateral complete cleft lip and palate at the stage of permanent dentition.

OBJECTIVE: Three-dimensional analysis of palate size and shape in patients with complete unilateral cleft lip and palate (UCLP) at the stage of permanent dentition. SUBJECTS: Thirty randomly selected dental casts of boys approximately 15 years old with complete UCLP and 28 dental casts of normal boys of the same age. INTERVENTIONS: All patients underwent lip repair according to Tennison with primary periosteoplasty (mean age 8.5 months) and palate repair by pushback and pharyngeal flap surgery (mean age 4.9 years). MAIN OUTCOME MEASURES: Data on the palate height in 210 defined locations. RESULTS: The palate in patients with UCLP was narrower throughout its whole extent, more anteriorly than posteriorly. From the canines posteriorly, it was also lower, and the difference as compared with controls increased in a posterior direction up to the level of second premolars (up to 30%) and then slightly diminished (to 21% between the first molars). The reduction of area of transverse sections reached 45% between premolars and 39% between first molars. The palate in the anterior portion was highest on the cleft side and in a posterior direction the maximum height of the palate shifted toward the midline and even beyond that line toward the noncleft side. Palatal height did not depend on dentoalveolar arch width. CONCLUSION: The smaller width and height of the palate confirm the substantially reduced space for the tongue in patients with UCLP. The reduction is only slightly larger than in previously examined patients with isolated cleft palate. Palatal vault is asymmetrical, highest anteriorly on the cleft side and posteriorly on the noncleft side.     

The basis for presurgical orthopedic treatment of infants with unilateral complete cleft lip and palate.

OBJECTIVE: The purpose of this study was to describe the posttreatment morphology of the upper part of the oral cavity of complete unilateral cleft lip and palate (UCLP) patients and to compare it to noncleft contemporaries. Patients were treated according to a protocol designed to keep a proper resting posture of the oral cavity. DESIGN: Retrospective study on dental casts. SETTING: The study was performed at a maxillofacial center serving a population of 2 million inhabitants. Data for noncleft subjects are the result of a longitudinal study at the same institution. PATIENTS: Twenty-one Caucasian UCLP patients (13 males, 8 females) aged 5 to 9 years with no other congenital anomalies and no postoperative orthodontic treatment. INTERVENTIONS: Each patient received 5 to 6 months of preoperative orthopedics with a passive plate and external nonelastic strapping with definitive lip repair at age 5 to 7 months, soft palate repair at 11 to 15 months, and hard palate repair with mucoperiosteal closure of the alveolus at 30 to 36 months. Each patient was compared to the mean values obtained from a longitudinal study of a group of 25 healthy noncleft children of the same ethnic group (11 males, 14 females). RESULTS: Analysis of dental casts indicated that 16 patients had a width, depth, and length of the alveolar arch in the range of the mean normal values minus two standard deviations. Their analyzed palates were flatter than normal. Six of 21 children had too small an alveolar arch for their ages, and they did not acquire a correct posture of the oral cavity. CONCLUSION: The results indicate that the upper part of the oral cavity of UCLP patients can reach the dimensions of noncleft contemporaries despite surgery.     

The relationship between arch dimensions and the 5-year index in the primary dentition of patients with complete UCLP.

OBJECTIVE: To compare dental arch dimensions of children in the primary dentition with repaired unilateral clefts of the lip and palate (UCLP) to a noncleft group of a similar age and determine how the dimensions of the cleft arches relate to an index of treatment outcome. METHOD: Dental study casts of 44 5- to 6-year-olds with complete UCLP (22 boys and 22 girls) from a single center, whose primary surgery had been carried out by one surgeon, were matched for age, sex, and ethnicity with dental study casts from a longitudinal growth study. Analysis of variance was used to ascertain differences in arch dimensions between the two groups. The cleft group casts were then assessed with an established index of surgical outcome, the 5-year-old index. Spearman's rank correlation coefficient was used to see how the arch dimensions of the cleft group related to the categories of the index. RESULTS AND CONCLUSIONS: Maxillary arch dimensions were significantly smaller in the cleft group than in the noncleft group, irrespective of sex (p < .05). In the mandibular arch, there was no difference between the cleft and noncleft groups (p > .05). Maxillary arch dimensions of the cleft group correlated significantly with the 5-year-old index for arch length and intercanine width (p < .05) but not intermolar width (p = .842). This would suggest that the 5-year-old index is a suitable tool for assessing the outcome of treatment in the primary dentition for anteroposterior and anterior transverse arch dimensions.     

Changes produced by presurgical orthopedic treatment before cheiloplasty in cleft lip and palate patients.

OBJECTIVE: The purpose of this study was to test the hypothesis that, with the use of preoperative treatment, the dimensions of the upper part of the oral cavity of an infant with unilateral cleft lip and palate (UCLP) become more similar to those of a noncleft infant. DESIGN: This was a retrospective study of upper dental casts taken at birth and prior to lip repair at 6 months of age. A treated group, an untreated group, and a group of noncleft contemporaries were compared cross-sectionally and longitudinally. Models were analyzed by the trigonometric method. SETTING: The study was performed at a maxillofacial center servicing a population of two million. PARTICIPANTS: The treated group consisted of 24 babies born after 1990 with UCLP that started presurgical treatment within 20 days of life. The untreated group consisted of 25 randomly selected UCLP casts taken at birth and 25 casts taken just before lip surgery. The noncleft group consisted of 25 full-term infants whose mothers participated in the longitudinal growth study. All participants belonged to the same ethnic group. INTERVENTIONS: Presurgical treatment consisted of the babies constantly wearing a thin, passive acrylic plate mimicking the normal palate and a slim adhesive tape fixed to the lip segments to bring them slightly together. RESULTS: The upper oral cavity in a newborn with UCLP was significantly larger than in a noncleft infant, the only exception being in the sagittal dimension. After presurgical treatment, the upper oral cavity was remodeled and slightly enlarged; there was a lesser difference from the noncleft at 6 months than at birth. The cleft in the alveolus reduced significantly, and the position of the incisive point improved. The group without presurgical treatment had no remodeling, and the growth dynamics were similar to the noncleft so that the dimensional differences from the normal remained the same as at birth. CONCLUSION: The morphological characteristics of the upper part of the mouth change if the functional conditions in the oral cavity are changed. Infants with presurgical orthopedics become more similar to noncleft contemporaries than those without presurgical orthopedics.     

单侧完全性唇腭裂患者牙弓宽度正畸扩弓治疗后的稳定性研究

目的探讨单侧完全性唇腭裂后牙反[牙合]患者正畸扩弓矫治后牙弓宽度的稳定性。方法已经完成保持的经过四角舌弓及固定矫治器正畸治疗的手术后单侧完全性唇腭裂患者20名（男性14名，女性6名），三维测量仪对治疗前、治疗后及保持后的研究模型进行尖牙间、第一、二双尖牙、第一磨牙间宽度以及基骨和牙槽弓宽度的测量。统计方法为配对资料的方差分析，两两比较用Fishe rLSD法。结果经过四角舌弓及固定矫治器治疗后单侧完全性唇腭裂患者上颌各段宽度均增加，差异有统计学意义；下颌除第一双尖牙外各段宽度变化不具统计学意义。正畸治疗后上颌牙弓宽度的增加在尖牙和双尖牙区大于磨牙区。保持结束后牙弓各段宽度较治疗后均有减小，其中上颌尖牙间宽度减小1．34±0．82mm（P〈0．05）、第一双尖牙间宽度减小1．52±0．78mm（P〈0．05）达到显著水平。但是保持结束后上颌各段的牙弓宽度仍大于治疗前，差异有统计学意义。结论经过四角舌弓及固定矫治器系统治疗后，单侧完全性唇腭裂患者上颌牙弓各段的宽度均显著增加；保持结束后上颌牙弓各段宽度虽有复发，但是大部分矫治结果能够保持。     

恒牙晚期单侧完全性唇腭裂患者正畸治疗临床疗效研究

目的　通过测量恒牙晚期单侧完全性唇腭裂（UCLP）患者术后牙牙合、软硬组织的相关数据,观察正畸治疗对患者面型、牙弓及咬合关系的临床疗效。方法　选择10例UCLP恒牙晚期（15～17岁）术后患者,采用上颌慢速扩弓联合固定矫治,对治疗前、扩弓保持半年后X线头颅侧位片及扩弓治疗前、扩弓结束后、保持半年后牙牙合模型相关数据进行测量。采用配对t检验和配伍组设计资料的方差分析的统计方法,2组之间的两两比较用最小显著差(LSD)检验。结果　UCLP患者在正畸治疗后,X线头颅侧位片在软硬组织部分测量数据上有显著性变化(P<0.01),牙弓宽度在尖牙和前磨牙区有明显增加（P<0.01）,前磨牙区宽度的增加能稳定保持（P<0.05）。结论　 恒牙晚期UCLP术后患者经正畸治疗,骨骼、面部软硬组织及咬合关系均有较理想的治疗效果。     

Early assessment of dental arch development in repaired unilateral cleft lip and unilateral cleft lip and palate versus controls.

OBJECTIVE: To evaluate dental arch relationships and dimensions, relative to an age matched noncleft sample, in Caucasian 3-year-old children with repaired unilateral cleft lip (UCL) or unilateral cleft lip and palate (UCLP). DESIGN: Prospective, cross-sectional, case-control study performed in Scotland, U.K. PARTICIPANTS: Eleven children with repaired unilateral cleft lip, 16 children with repaired unilateral cleft lip and palate, and 78 children as controls. MAIN OUTCOME MEASURES: Dental arch relationships and linear arch dimensions. RESULTS: Prevalence of Class III incisor relationship was 31.3% in children with unilateral cleft lip and palate compared with 9.1% in children with unilateral cleft lip. A buccal crossbite was present in 36% of children with unilateral cleft lip, compared with 75.6% of children with unilateral cleft lip and palate.Mean linear maxillary arch dimensions did not differ significantly between children with unilateral cleft lip and the controls. Except for second intermolar width, statistically significant differences existed in mean linear maxillary arch dimensions between the unilateral cleft lip and the unilateral cleft lip and palate groups; the mean linear maxillary arch dimensions were significantly greater in the control group than in the unilateral cleft lip and palate group. The mean cleft-affected anterior quadrant length appeared to be the arch dimension with the greatest power of discrimination among the three groups. There were no significant differences in mean linear mandibular arch dimensions among the three groups. CONCLUSIONS: Anterior crossbite was almost three times more common in the unilateral cleft lip and palate group than in the unilateral cleft lip group. Mean linear maxillary arch dimensions differed significantly between the unilateral cleft lip and palate group and the control group. There were no significant differences in mean linear maxillary arch dimensions between unilateral cleft lip and controls or between mean linear mandibular arch dimensions for unilateral cleft lip, unilateral cleft lip and palate, and controls.     

Influence of early hard palate closure in unilateral and bilateral cleft lip and palate on maxillary transverse growth during the first four years of age.

OBJECTIVE: To evaluate and compare the effects of early primary closure of the hard palate on the anterior and posterior width of the maxillary arch in children with bilateral (BCLP) and unilateral (UCLP) cleft lip and palate during the first 4 years of life. DESIGN: A retrospective, mixed-longitudinal study. SETTING: Cleft Palate Center of the University of Erlangen-Nuremberg. SUBJECTS AND METHODS: The present investigation analyzes longitudinally 42 children with UCLP and 8 children with BCLP between 1996 and 2000 with early simultaneous primary closure of lip and hard palate (4 to 5 months). Palatal arch width was measured on dental casts with a computer-controlled three-dimensional digitizing system, and their growth velocities were calculated from consecutive periods (mean follow-up 39 months). Differences in growth velocities were compared with those of 25 children with UCLP and 15 children with BCLP with delayed closure of hard palate (12 to 14 months). RESULTS AND CONCLUSIONS: There was no significant difference in terms of anterior and posterior maxillary width between early and delayed closure of hard palate within the first 4 years of life.     

替牙期骨性Ⅲ类单侧完全性唇腭裂患者修复术后口周力的分布特征

目的:通过与同龄非唇腭裂正常 儿童比较,研究替牙期骨性Ⅲ类单侧完全性唇腭裂(unilateral cleft lip and palate,UCLP)患者上下颌不同位点口周力的特征。 方法:选取替牙期6～12岁UCLP患者20例(男14例,女6例)为UCLP组;同龄正常 儿童21例(男14例,女7例)为对照组。采用口周肌压力采集系统测量每个研究对象息止 位时双侧上下颌中切牙、尖牙或乳尖牙、第一前磨牙或乳磨牙、第一恒磨牙的唇颊、舌腭侧龈缘的口周力。使用SPSS 25.0统计软件对数据进行统计分析。 结果:1．UCLP组上颌口周力裂侧大于非裂侧( P<0.05),下颌口周力两侧无差异( P>0.05)。2. UCLP组上颌口周力大于对照组( P<0.05),两组上颌唇颊侧的口周力均在第一前磨牙/乳磨牙区最大,在中切牙区最小。3. UCLP组下颌唇颊侧口周力小于对照组( P<0.01),下颌中切牙舌侧区UCLP组大于对照组( P<0.05)。4. UCLP组上颌牙弓内外口周力差值大于对照组( P<0.05),下颌差值小于对照组( P<0.01)。 结论:替牙期骨性Ⅲ类UCLP患者口周力较同龄非唇腭裂正常 儿童存在异常。     

单侧完全性唇腭裂术后牙弓问横向关系的不调及正畸矫治后变化的探讨

目的 探讨单侧完全性唇腭裂术后患者上下颌牙弓间横向关系以及正畸治疗对上颌牙弓的影响。方法 对84名单侧完全性唇腭裂术后患者的错(牙合)畸形和上下颌颌间关系进行研究;并对36名唇腭裂术后患者进行正畸治疗前后的牙(牙合)模型进行测量分析上颌牙弓宽度的变化。结果 (1)单侧完全性唇腭裂术后60.7％的患者出现牙弓间横向关系的不协调,双尖牙区较易受累。(2)在出现牙弓间横向关系不调的患者中,双侧后牙反(牙合)者为60％。(3)正畸治疗后上颌牙弓的尖牙、第一、第二双尖牙间各自的宽度均有显著增加,第一磨牙间宽度变化不显著。上颌第一、第二双尖牙间各自宽度较尖牙间、第一磨牙间宽度增加显著。结论 单侧完全性唇腭裂术后患者上颌宽度的发育受到明显的限制,牙弓间横向关系不协调的比率较高,以双尖牙区为主;正畸矫治扩弓的重点应在双尖牙区。     

单侧完全性唇腭裂术后患者牙弓间宽度不调的矫治

目的　通过对单侧完全性唇腭裂术后患者上下颌间牙弓宽度不调的研究及对患者正畸治疗的临床观察 ,总结该类患者正畸治疗的特点。方法　对 4 8例单侧完全性唇腭裂术后患者进行临床检查 ,记录其上下牙弓间的宽度关系 ;根据患者错情况制定不同的治疗方案进行临床治疗。结果　 (1)单侧完全性唇腭裂术后患者中出现上下颌牙弓宽度不调的比率为 6 0 .4 % ,双侧后牙反为 33.3% ,单侧后牙反为 16 .7%。男女之间差异无显著性。 (2 )宽度不调以双尖牙区为重 ,上尖牙区是扩弓治疗的重点。 (3)磨牙区牙弓宽度的不协调常较轻微 ,一些患者甚至上颌最后磨牙区略宽 ,对 5例患者 (占 10 4 % )进行了上颌磨牙的腭向移动。结论　单侧完全性唇腭裂患者正畸治疗中上颌多需扩弓 ,且扩弓潜力较大。对于严重拥挤的患者 ,拔牙决定应在扩弓后作出。扩弓治疗应在牙槽突植骨前进行 ,扩弓后需延长保持时间     

Evaluation of the intercanine distance in newborns with cleft lip and palate using 3D digital casts

Objective

The purpose of this present study was to compare, by means of 3D digital casts, the anterior transverse dimension of the dental arch of newborns with and without cleft lip and palate.

Material and Methods

The sample was composed of ninety-four children aged from 3 to 9 months divided into three study groups: Group I - children without craniofacial deformities (control group); Group II - children with unilateral cleft lip and palate; Group III - children with bilateral cleft lip and palate. Impressions were executed before lip and palate repair in patients with clefts. Dental casts were digitized using a 3D scanner linked to a computer. Measurements of the intercanine distance were measured on the digital casts. Intergroup comparisons were performed using ANOVA (p<0.05).

Results

The results showed a mean of 36.5 mm for unilateral cleft lip and palate group, 34.8 mm for bilateral cleft lip and palate group and 27.52 mm for the control group. There was a statistically significant difference between the control group and both groups of patients with cleft lip and palate. There was no statistically significant difference between complete unilateral and bilateral cleft lip and palate groups.

Conclusions

Patients with complete cleft lip and palate were born with an increased anterior dimension of the maxillary dental arch compared to non cleft patients.     

Transverse changes after surgical closure of complete cleft lip, alveolus and palate

Surgery for patients with unilateral (UCLP) and bilateral (BCLP) complete cleft lip, alveolus and palate has a considerable influence upon craniofacial growth. With respect to this, the cleft team at Hannover Medical School has attempted to reduce necessary surgical interventions to labioplasty, palatoplasty and veloplasty. Still, the effects of these operations influence maxillary growth to an extent which requires orthodontic treatment in all patients. This study focuses upon the transverse alterations of the alveolar arch and the deciduous dentition after lip and palate surgery. Dental casts prior to any surgical intervention and after labioplasty and complete palaotoplasty of the hard and soft palate were measured for transverse changes by using anatomical landmarks. The results indicate a significant occurrence of anterior relative to posterior arch width loss for both UCLP and BCLP patients. Orthodontic treatment should be planned and performed with respect to these findings in order to support craniofacial growth and prevent maxillary dental arch deficiency. Received: 2 November 1998 / Accepted: 15 February 1999     

Photographs of study casts: an alternative medium for rating dental arch relationships in unilateral cleft lip and palate.

OBJECTIVE: To investigate the reliability of using photographs of study casts as an alternative to casts for rating dental arch relationships. DESIGN: Repeated-measures study. SETTING: Cleft Palate Center of the University Medical Center Nijmegen, Nijmegen, The Netherlands. PATIENTS: Records of children with complete unilateral cleft lip and palate (UCLP) (n = 49) at the age of 9 years were included. MEAN OUTCOME MEASURE(S): Statistics of intra- and interexaminer agreement. RESULTS: No significant differences were found between the rating of dental casts and photographs of dental casts, using the Goslon Yardstick. CONCLUSIONS: Photographs of dental casts provide a consistent, reproducible method for rating dental arch relationships in patients with UCLP at the age of 9 years and provide a reliable alternative to the application of the Goslon Yardstick on dental casts.     

Palate height: another indicator of surgical outcome in unilateral cleft lip and palate?

OBJECTIVE: To determine whether palate height and maxillary arch depth are systematically related to the surgical center at which primary repair in unilateral cleft lip and palate (UCLP) was carried out. DESIGN: A retrospective comparison based on study casts of consecutive cases of UCLP obtained at age 9 years from six different centers. The observer who conducted measurements was blinded to the source of individual records. SETTING: The patients whose records were analyzed received all their surgical care in a national health service setting in six different northern European centers and regions. PATIENTS: Patients were consecutively treated Caucasian children with non-syndromic complete UCLP born in the period 1976 to 1979. MAIN OUTCOME MEASURES: The main outcome measures for the original study were craniofacial form, dental arch relationships, nasolabial appearance, and speech. This report focuses on measurements of anterior maxillary arch depth and palate height. Results: Anterior arch depth and anterior palate height showed some variation among the centers. There was a tendency for anterior arch depth and palate height to also be reduced at centers at which patients showed unfavorable dental arch relationships. CONCLUSIONS: Anterior arch depth and palate height might be considered in future studies of surgical outcome and in their possible relationship to problems of articulation.     

The effects of palatoplasty and pre-surgical infant orthopedic treatment on occlusion in unilateral cleft lip and palate patients

PurposeThe aim of this study was to evaluate the effect of pre-surgical infant orthopedic treatment (Hotz plate) and type of palatoplasty on the dental arch relationship and the dental arch morphology of unilateral cleft lip and palate (UCLP) patients.Materials and methodsSeventy-four children with UCLP were divided into three groups. One group had undergone one-stage palatoplasty without Hotz plate (OSP w/o H), the second had undergone one-stage palatoplasty with Hotz plate (OSP w/H), and the third had undergone two-stage palatoplasty with Hotz plate (TSP w/H). We evaluated the dental models which were taken during initial examination at our orthodontic clinic, using the Goslon Yardstick, the 5-year-old index, and dental model analysis.ResultsRegarding both indices, there were no significant differences among the three groups. However, the dental arch width between maxillary deciduous canines in OSP w/H and TSP w/H was significantly greater than that of OSP w/o H. The dental arch width at the maxillary deciduous second molars in TSP w/H was significantly greater than in OSP w/H and OSP w/o H.ConclusionDental arch relationship in UCLP patients was not influenced by the type of palatoplasty and the use of pre-surgical infant orthopedic treatment. Our results suggest that pre-surgical infant orthopedic treatment results in the increase of anterior dental width, whereas two-stage palatoplasty is significantly effective for increasing posterior dental width in UCLP patients.     

Dental age in children with a complete unilateral cleft lip and palate.

OBJECTIVE: To assess dental age in children with a complete unilateral cleft lip and palate and to compare this with a noncleft control group. DESIGN: Two-group, mixed-longitudinal cohort study. SETTING: Cleft group from an academic center for cleft lip and palate treatment. Noncleft control group from the same population. PATIENTS: Participants included 70 Caucasian children with a full complement of teeth and a complete unilateral cleft lip and palate (45 boys and 25 girls) from the Cleft Palate Craniofacial Center at the Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands. The control group (90 boys and 91 girls) was taken from the Nijmegen Growth Study. MAIN OUTCOME MEASURE: Dental age was assessed on orthopantomograms. In the unilateral cleft lip and palate group, linear interpolation in individual age curves was applied to obtain the dental age at 5, 9.5, and 14 years of age. For these ages, a comparison was made with the noncleft control group. RESULTS: Boys and girls with a unilateral cleft lip and palate showed a significant delay in dental age, as compared with their noncleft peers at all three ages. This delay was more pronounced in boys than in girls. The gender effect was significant at chronological ages 5 and 14 years. CONCLUSIONS: Children with a complete unilateral cleft lip and palate have a delay in dental age, compared with noncleft children.     

BITE FORCE EVALUATION IN SUBJECTS WITH CLEFT LIP AND PALATE

The purpose of this study was to evaluate the masticatory function of subjects with cleft lip and palate by analyzing the bite force developed by these individuals. Bite force was evaluated in a group of 27 individuals with repaired unilateral cleft lip and palate (14 males and 13 females – aged 18-26 years) and compared to the data achieved from a group of 20 noncleft subjects (10 males and 10 females – aged 18-26 years). Measurement was achieved on three positions within the dental arch (incisors, right molars and left molars), three times at each position considering the highest value for each one. Statistical analysis was performed by ANOVA and Mann-Whitney test (α = 5%). There was a significant deficit in bite force in male individuals with cleft lip and palate compared to the male control group (p=0.02, p=0.004, p=0.003 for incisors, right and left molars, respectively). For the female group, the difference was not statistically significant (p=0.79, p=0.06, p=0.47). In the group of individuals with clefts, 92.6% were under orthodontic treatment, which could be a reason for the present findings, since it can decrease the bite force more remarkably in males than in females. In conclusion, the bite force is significantly reduced in men when comparing the cleft group to the noncleft group. In females, this reduction was not significant in the same way. However, the main reason for this reduction and for the different behavior between genders should be further investigated.     

Dental arch width stability after quadhelix and edgewise treatment in complete unilateral cleft lip and palate

OBJECTIVE: To evaluate the transverse stability of the dental arch in unilateral cleft lip and palate (UCLP) patients after orthodontic treatment with quadhelix and edgewise appliances. MATERIALS AND METHODS: Twenty repaired complete UCLP patients with posterior crossbites were chosen as the study subjects. All had ceased retention at least 15 months previously. Measurements were carried out directly on the pretreatment, posttreatment, and postretention study models using a three-dimensional dental cast analyzer. The interdental widths were measured for the canines, first premolars, second premolars, first molars, basal bone, and the alveolar arch. Two-way analysis of variance and Fisher's LSD was performed in comparing the difference between intervals. RESULTS: Lower inter-first-premolar width and upper arch widths of each region increased significantly (P < .05) after orthodontic treatment. The expansion was greater in the anterior than the posterior region in the upper arch, and the greatest increase was in the upper first premolar region. The upper arch width decreased after retention, with the decrease of the arch width in the upper canine (1.3 +/- 0.8 mm) and first premolar (1.5 +/- 0.8 mm) regions being statistically significant. The increased upper arch width in each region and the lower inter-first-premolar width maintained significant expansion after retention. CONCLUSIONS: The widths of the dental arch increased significantly after expansion with a quadhelix followed by preadjusted edgewise treatment. Relapse occurred, especially in the upper canine and first premolar region, but most of the treatment effect on the upper arch remained after retention.