Frequency and severity of malocclusions in patients with statutory health insurance in a German orthodontic practice in North Rhine Westphalia - a multi-part cross-sectional study over a 20-year period.

OBJECTIVE: Since 2002, patients with statutory health insurance in Germany must undergo an assessment of orthodontic treatment need using the "Kieferorthopädische Indikationsguppen" (KIG; orthodontic indication groups) classification system. According to this system, tooth and jaw misalignment are divided into 11 subgroups and five grades. The objectives of this study were to determine the distribution of KIG classifications in patients with statutory insurance of a German orthodontic practice (North Rhine, Germany) and to analyze changes over a 20-year period. MATERIALS AND METHODS: Since the introduction of the KIG index in 2002, 4940 statutorily insured patients over a 20-year period (2330 m, 2610 f, min 3.2, max 49.5 years, peak between 10 and 12 years) were classified at their first appointment. According to the valid guidelines of the statutory health insurance (GKV), the division was made into the highest possible KIG classification. Multiple entries were thus not made. In accordance with the operating cycles of the practice, the progression was divided into four 5-year periods. RESULTS: Over a 20-year period, 24.98% of the patients were assigned to the classification "D". 86.52% of the patients were among the 6 most frequently ("D", "E", "K", "S", "P" and "M", > 10% each) and only 13.49% among the 5 least frequently recorded classifications ("U", "B", "T", "O" and "A", < 5% each). CONCLUSION: The distribution of the 6 most frequent and the 5 least frequent KIG classifications was constant over a 20-year-period. Among all possible tooth and jaw misalignment variants, the sagittal classifications "D" and "M" represent the most frequent malocclusions. CLINICAL RELEVANCE: The results and their comparison with historical data show that both frequency and severity of tooth and jaw misalignment with orthodontic treatment need appear identical for patients with statutory health insurance over a 20-year period.

Outcome differences after orthodontic camouflage treatment in hypo- and hyperdivergent patients - A retrospective cephalometric investigation.

OBJECTIVES: To compare differences in outcome in skeletal and dental parameters in hypo- and hyperdivergent Class II patients after extraction of upper first premolars and comprehensive orthodontic treatment. MATERIALS AND METHODS: 37 Class-II-patients with dental camouflage treatment were divided into a hypo- (n = 18) or a hyperdivergent (n = 19) group depending on the mandibular plane angle (hypo: < 34° or hyper: ≥ 34°). Lateral cephalograms were available before (T1) and after (T2) treatment and were analyzed with customized measurements. Data from a growth survey served as a control and were used to calculate the actual treatment effect. Data were analyzed by one-sample Student's t-tests and independent Student's t-tests. Statistical significance was set at p < 0.05. RESULTS: The measurements showed similar changes in both groups. The effects were mainly dentoalveolar. Hypodivergent patients showed an almost equal increase in anterior and posterior facial height, while hyperdivergent patients only showed an increase in anterior facial height. CONCLUSIONS: In hyperdivergent patients, the anterior facial height increases despite camouflage treatment. This indicates a tendency towards bite opening and backward rotation of the mandible. Hypodivergent patients do not experience deepening of the bite. CLINICAL RELEVANCE: In hyperdivergent patients with upper first premolars extraction the anterior facial height increased differently than in hypodivergent patients. This should be considered if a bite opening is a possible contraindication to treatment.

Age-dependent effects on palate volume and morphology during orthodontic RME treatment.

OBJECTIVES: Rapid maxillary expansion (RME) shows different age-dependent effects. It has been shown that RME leads to a parallel expansion prior to the age of 10, while later and especially from the age of 12, a V-shaped expansion happens (transverse, anterior > posterior; horizontal, inferior > superior). However, it is not clear to what extent these effects influence palatal volume and morphology and eventually maxillary functional space. The aim of the present study was to examine possible age-related effects of treatment with a dental anchored RME appliance upon volume and width/height ratio of the anterior and posterior palate. MATERIALS AND METHODS: Sixty children and adolescents with documented treatment histories after RME were divided into three equal groups according to age at treatment begin (PG 1, < 10 years, n=20; PG 2, 10 ≤ 12 years, n=20; PG 3, > 12 years, n=20). Maxillary dental casts before and after therapy were digitised. Changes in palatal volume were determined using 3D analyses. RESULTS: In all patients, the palatal volume increases significantly after RME. Older patients experienced smaller increases in total and posterior volume in absolute and percentage terms. The anterior palate volume increases are almost equal in all patients. Since palatal width increases more markedly than palatal height, the width/height ratio always increases. Except for the posterior region in PG 3, its increase is significant in all groups, both anteriorly and posteriorly. After successful RME, the palatal morphology appears normal anteriorly in PG 1, PG 2 and PG 3 and rather steep posteriorly in PG 3. CONCLUSIONS: RME treatment with identical force application causes different, age-dependent effects upon palate volume and morphology. Width changes have a greater influence on palate volume than height changes. CLINICAL RELEVANCE: It is preferable to use an RME prior to the age of 10 if homogeneous changes of the anterior and posterior palate regarding maxillary symmetry and functional space are desired.

Effects of fixed functional orthodontic treatment in hypodivergent and hyperdivergent class II patients-a retrospective cephalometric investigation.

OBJECTIVE: To compare skeletal and dentoalveolar changes after orthodontic treatment of class II malocclusion in patients with hypodivergent and hyperdivergent growth patterns through cast splint fixed functional appliances (FFA). MATERIALS AND METHODS: N = 42 out of n = 47 patients with mandibular plane angles < 34° or ≥ 34° were divided into a hypodivergent (n = 24) and a hyperdivergent (n = 18) group. All patients received a single-step mandibular advancement protocol through an FFA. Lateral cephalograms were analyzed after initial leveling and alignment (T1) and immediately after FFA removal (T2). The therapeutic effect was calculated through comparison with age-matched controls from a growth survey. Statistical significance was set at p < 0.05. RESULTS: Hypodivergent and hyperdivergent patients showed different treatment outcomes, but significant differences existed only for overbite and interincisal angle. Nearly all measurements suggested similar treatment-related changes for both groups with exception for dentoalveolar parameters. CONCLUSION: Treatment with FFA causes similar skeletal and dentoalveolar effects in hypodivergent and in hyperdivergent patients. The correction of overjet and molar relationship is mainly caused by dentoalveolar changes. CLINICAL RELEVANCE: Hyperdivergent patients do not respond unfavorably to FFA treatment compared to hypodivergent patients. Lower incisor protrusion occurs more pronounced in hypodivergent patients. The growth pattern ought to be considered when choosing FFA for class II treatment.

Impact of rapid maxillary expansion on palatal morphology at different dentition stages.

OBJECTIVE: Rapid maxillary expansion (RME) is an established and frequently used procedure to overcome maxillary constriction. In-depth studies about morphological changes of the alveolar process and its immediate surroundings are missing. Therefore, the aim of the present study was to examine the treatment effects of a dentally anchored, rapid maxillary expander at different dentition stages upon palatal width, height and shape. MATERIAL AND METHODS: The dental casts of 114 patients-taken immediately before and after RME-were three-dimensionally analysed. Depending on the dentition stage, the patients were divided into two groups (each n = 57, group 1, early mixed dentition; group 2, late mixed or permanent dentition). RESULTS: The width increases were highly significant, both in the overall and in the individual groups (p < 0.001). While the width increase was greater in the posterior area than anteriorly in the early group, the widening in the late group happened significantly greater anteriorly than posteriorly. Palatal height increased anteriorly and posteriorly in both groups to a significant extent (p < 0.001). The height increase was more pronounced in the anterior region than in the posterior region in the late group. The palatine index according to Kim revealed a change in palatal morphology both anteriorly and posteriorly in the early group but only anteriorly in the late group. CONCLUSIONS: Maxillary expansion occurs more parallel in early treatment compared to V-shaped opening in the later treatment approach. CLINICAL RELEVANCE: RME is more advantageous in an early dentition.

Changes of epiglottis and hyoid bone position after orthodontic treatment with cast splint fixed functional appliances.

OBJECTIVES: Angle Class II malocclusions including a retrognathic mandible are the most frequent orthodontic problems. Both removable and fixed functional appliances can be used for mandibular advancement. Mandibular advancement after treatment with any fixed functional appliance has numerous therapeutic effects, such as stretching of masticatory muscles, ligaments, membranes and surrounding soft tissues, thus causing positional changes of the hyoid bone and epiglottis. This retrospective study investigates and compares treatment effects upon epiglottis- and hyoid bone position and posterior airway space in class II patients who received mandibular advancement through two different cast splint fixed functional appliances. MATERIAL AND METHODS: Two groups of 21 patients each ('Functional Mandibular Advancer' (FMA) and Herbst appliance) were investigated. The same experienced orthodontist performed the treatment in all patients, employing a single-step advancement protocol. The mandible always received initial protrusion into an edge-to-edge position. Conventional lateral cephalograms were available pre-treatment (T1) and immediately after appliance removal (T2) for all patients. The measurements comprised (I) hyoid bone, (II) epiglottis or (III) posterior airway space. Treatment-related changes were analysed with one-sample Student's t tests for intragroup comparisons and independent Student's t tests for intergroup comparisons. Statistical significance was set at p < 0.05. RESULTS: Measurements of the hyoid bone showed mostly increases for both appliances after treatment. Intergroup comparisons were not significant for FMA patients but significant for selected measurements in Herbst appliance patients. Intergroup comparisons showed insignificant changes. The posterior airway space was always insignificantly increased after treatment. The greatest increase was found caudally. Intergroup comparisons showed insignificant changes. CONCLUSIONS: Both fixed functional appliances cause an anterior and caudal displacement of epiglottis and hyoid bone and enlarge the posterior airway space. The therapeutic effects of the Herbst appliance are slightly larger, although not significantly. CLINICAL RELEVANCE: Treatment with either Herbst appliance of FMA alters the hyoid bone position and enlarges the posterior airway space. Still, long-term data are as yet unavailable; it remains unknown if the effects upon posterior airway space remain stable, and if a resulting posterior airway space enlargement may have clinical influence upon obstructive sleep apnoea syndrome.

Differential skeletal and dental effects after orthodontic treatment with bite jumping appliance or activator: a retrospective cephalometric study.

OBJECTIVES: The aim of this retrospective cephalometric study was to compare treatment outcomes with "bite jumping appliance" (BJA) or Andresen-Häupl type activator. It especially focused on skeletal and dental structures in patients with class II malocclusion. The study hypothesis was that differences in treatment-related changes would occur between patients treated with BJA or activator. MATERIAL AND METHODS: Pre- and posttreatment lateral cephalograms of 73 patients with a class II malocclusion were analyzed. Thirty-seven patients (22 females, 15 males) received treatment with a BJA (pretreatment age 11.1 ± 1.07 years) and 36 patients (20 females, 16 males) with an activator (pretreatment age 11.3 ± 1.12 years). Treatment time was 14.0 ± 1.8 months with BJA and 12.0 ± 2.0 months with activator. Paired t tests were used for intragroup and t tests for independent samples for intergroup comparisons. Results were considered statistically significant at P < 0.05. RESULTS: The comparison of sagittal and vertical skeletal changes after BJA and activator treatment did not reveal significant differences. Significant changes occurred for lower incisor inclination (P = 0.0367) and overjet (P = 0.0125) only. The reduction of overjet and proclination of lower incisors were more pronounced in BJA patients. CONCLUSIONS: Both "bite jumping appliance" (BJA) and Andresen-Häupl type activator were able to improve the occlusion of patients with a class II malocclusion. Dental effects were more pronounced for the BJA. CLINICAL RELEVANCE: Marked lower incisor proclination contributed significantly to overjet correction in BJA patients. This ought to be respected when choosing a removable functional appliance for patients whose lower incisors are already proclined prior to treatment.

A retrospective cephalometric investigation of two fixed functional orthodontic appliances in class II treatment: Functional Mandibular Advancer vs. Herbst appliance.

OBJECTIVE: The objective of the study is to compare skeletal and dental changes in class II patients treated with fixed functional appliances (FFA) that pursue different biomechanical concepts: (1) FMA (Functional Mandibular Advancer) from first maxillary molar to first mandibular molar through inclined planes and (2) Herbst appliance from first maxillary molar to lower first bicuspid through a rod-and-tube mechanism. MATERIALS AND METHODS: Forty-two equally distributed patients were treated with FMA (21) and Herbst appliance (21), following a single-step advancement protocol. Lateral cephalograms were available before treatment and immediately after removal of the FFA. The lateral cephalograms were analyzed with customized linear measurements. The actual therapeutic effect was then calculated through comparison with data from a growth survey. Additionally, the ratio of skeletal and dental contributions to molar and overjet correction for both FFA was calculated. Data was analyzed by means of one-sample Student's t tests and independent Student's t tests. Statistical significance was set at p < 0.05. RESULTS: Although differences between FMA and Herbst appliance were found, intergroup comparisons showed no statistically significant differences. Almost all measurements resulted in comparable changes for both appliances. Statistically significant dental changes occurred with both appliances. Dentoalveolar contribution to the treatment effect was ≥70%, thus always resulting in ≤30% for skeletal alterations. CONCLUSION: FMA and Herbst appliance usage results in comparable skeletal and dental treatment effects despite different biomechanical approaches. CLINICAL RELEVANCE: Treatment leads to overjet and molar relationship correction that is mainly caused by significant dentoalveolar changes.

Soft tissue profile changes after Functional Mandibular Advancer or Herbst appliance treatment in class II patients.

OBJECTIVE: The objective of the present study is to compare the effects on soft tissue profile in class II patients after treatment with either "Functional Mandibular Advancer" (FMA) or Herbst appliance. MATERIALS AND METHODS: The study included n = 42 patients treated with either FMA (n = 21) or Herbst appliance (n = 21) by the same experienced orthodontist. The treatment followed a single-step advancement protocol. Lateral cephalograms were analyzed through a set of customized measurements. The actual therapeutic effect was calculated using data from a growth survey. After testing for normal distribution and homogeneity of variance, data were analyzed by one-sample Student's t tests and independent Student's t tests. Statistical significance was set at p < 0.05. RESULTS: For both FFAs, significant upper lip retrusion, increase in lower lip's thickness, and length of the lower face occurred. Additionally, significant lower lip retrusion and straightening of the profile were found in FMA and Herbst appliance patients. All remaining variables revealed no significant differences. CONCLUSIONS: Treatment-related changes on the facial soft tissue profile could be regarded similar in class II patients treated with FMA or Herbst appliance. No treatment-related changes that were specific for FMA or Herbst appliance could be identified. Only moderate changes were noted comparing pre- and posttreatment soft tissue profiles. CLINICAL RELEVANCE: Despite proven differences in skeletal and dental treatment effects, the facial profile has not to be taken into consideration when choosing between FMA and Herbst appliance for class II treatment.

Anatomic landmarks and availability of bone for placement of orthodontic mini-implants for normal and short maxillary body lengths.

INTRODUCTION: Increasing numbers of orthodontic mini-implants are placed in the anterior maxilla. To our knowledge, bone levels and root proximity of patients with cephalometrically short maxillae have not been investigated before. The first, second, and third rugae were used as clinical reference lines, and the aim of this study was to measure bone availability in that area by comparing patients with short and normal maxillary body lengths. METHODS: The sample consisted of 21 patients in each group: short maxillary body length and normal maxillary body length. The patients' study models were bisected, and the outline of the palatal contour was marked on the surface. The models were scanned, and the palatal contours were superimposed on the palatal structures of their respective initial cephalometric headfilms, and the vertical and oblique bone levels of the sagittal plane were compared using the Student t test. The level of significance was set at P <0.05. RESULTS: Compared with maxillae of normal maxillary body length, less bone was available in maxillae of short maxillary body length. However, the differences did not reach clinical or statistical significance (P >0.05) at the third rugae. CONCLUSIONS: Almost equivalent average bone depth at the third rugae in patients with normal and short maxillary body lengths suggests that this site can be used for 8-mm long obliquely inserted orthodontic mini-implants.

The most distal palatal ruga for placement of orthodontic mini-implants.

OBJECTIVE: To evaluate the stability and bone availability of the most distal (third) palatal ruga, as an anatomical region for safe insertion of orthodontic mini-implants (OMIs) in the anterior palate. STUDY DESIGN: Orthodontic records of 35 patients were analysed. Initial (T1) and final (T2) study models were bisected and the outline of the palatal contour was marked on the surface. Models were scanned and the palatal contours were superimposed on the palatal structures on the respective initial and final cephalometric images. Cephalometric measurements were used to assess vertical (3rdRug-PP, 2ndRug-PP, and 1stRug-PP), and oblique bone levels (3rdRug-U1, 2ndRug-U1, 1stRug-U1, and 3rdRug-U1(o)). Paired Student's t-test was used to compare measurements between T1 and T2. RESULTS: The position of the third palatal ruga remained stable during orthodontic treatment (Δ2ndRug-3rdRug P = 0.1mm; P = 0.61 and Δ1stRug-3rdRug P = 0.2mm; P = 0.39). Bone availability also remained adequate (3rdRug-U1T2 (o) = 9.9mm). CONCLUSION: The third palatal ruga is a reliable clinical landmark to evaluate bone availability for the placement of OMIs in the anterior palate.

Three dimensional anatomical exploration of the anterior hard palate at the level of the third ruga for the placement of mini-implants--a cone-beam CT study.

AIM: The aim of this retrospective investigation was to measure vertical bone thickness on the hard palate, determine areas with adequate bone for the insertion of orthodontic mini-implants (MIs), and provide clinical guidelines for identification of those areas. MATERIALS AND METHODS: Pre-treatment records of 1007 patients were reviewed by a single examiner. A total of 125 records fulfilled the inclusion criteria and were further investigated. Bone measurements were performed on cone-beam computed tomography scans, at a 90° angle to the bone surface, on 28 predetermined and standardized points on the hard palate. Bone thickness at various areas was associated to clinically identifiable areas on the hard palate by means of pre-treatment plaster models. RESULTS: Bone thickness ranged between 1.51 and 13.86 mm (total thickness) and 0.33 and 1.65 mm (cortical bone thickness), respectively. Bone thickness was highest in the anterior palate and decreased significantly towards more posterior areas. Plaster model analysis revealed that bone thickness was highest at the level of the third palatal ruga. CONCLUSIONS: The areas on the anterior palate with adequate bone thickness for successful insertion of orthodontic MI correspond to the region of the third palatal ruga. These results provide stable and clinically identifiable landmarks for the insertion of palatal MIs.

An active, skeletally anchored transpalatal appliance for derotation, distalization and vertical control of maxillary first molars.

OBJECTIVE: The objective of this investigation was to evaluate treatment outcomes of the skeletally anchored 'Frog' appliance. DESIGN: A single-centre, retrospective study was performed. SETTING: Private orthodontic practice. PARTICIPANTS: Patients who had undergone comprehensive orthodontic treatment with the skeletally anchored 'Frog' appliance. METHODS: 43 participants (20 males and 23 females) who had received treatment with the skeletally anchored 'Frog' appliance where included. In order to explore dentoalveolar and skeletal treatment outcomes, pre- (T1) and post- (T2) treatment measurements were performed on patients' plaster models and cephalometric images. Comparisons between T1 and T2 were made by means of a Student's t-test. All statistical analyses were conducted at the 0·05 level of statistical significance. RESULTS: Study model analysis revealed a statistically significant derotation of maxillary molars (µΔT2-T1=9·5°, P<0·001) as well as an increase in transverse arch dimensions at the end of treatment (µΔT2-T1=2·2 mm, P<0·001). Cephalometric changes included bodily distalization of maxillary molars (µΔ(T2-T1)=-1·9 mm, P<0·001), as well as noticeable angular displacement (µΔT2-T1=4·1°, P=0·004). No significant anchorage loss was observed, as displayed by the limited change in maxillary incisor position (µΔ(T1-T2)=0·2 mm, P=0·45). In addition, excellent vertical control of the maxillary molars was achieved, with no change in the mandibular plane (ML/NSL) angle (µΔT2-T1=0·3°, P=0·38). CONCLUSIONS: The skeletal 'Frog' is effective in derotating and distalizing maxillary molars without anchorage loss and with excellent vertical control.

Clinical outcomes of cases with missing lateral incisors treated with the 'T'-Mesialslider.

The objective of this article is to review the fabrication and activation procedures of the 'T'-Mesialslider and to present the clinical outcomes in cases where canine substitution is the treatment of choice for missing maxillary lateral incisors. The 'T'-Mesialslider allows for effective mesial translation of the canines and the posterior dentition, without significant loss of anterior anchorage and with good vertical control. Possible adverse effects of the appliance and clinical recommendations for their management are also discussed. In canine substitution cases with high anchorage demands, the 'T'-Mesialslider provides an effective treatment option.

Prevalence of KIG-grades 3-5 in an orthodontic practice in North Rhine Westphalia compared with results of the DMS•6 and with KZBV data.

BACKGROUND AND AIM: The prevalence of tooth and jaw malocclusions in 8- to 9-year-olds was surveyed in a nationwide setting as part of the orthodontic module of the Sixth German Study on Oral Health (DMS•6), using the orthodontic indication groups (KIG) as index. Aim of this study was the detection of the prevalence of malocclusions requiring treatment according to the KIG index in statutorily insured patients of an orthodontic practice in North Rhine Westphalia, Germany, and to compare results with corresponding DMS•6 and KZBV data. PATIENTS AND METHODS: Between 2017-2021, n = 953 statutorily insured patients called for an initial consultation and subsequent determination of the KIG-classification and -grades. The malocclusions were classified and graded in the highest possible KIG-grade according to valid SHI guidelines. Multiple classifications were not recorded. KIG-grade > 3 according to the valid guidelines was detected in n = 815 patients. Since the DMS•6 does not contain information on KIG classifications "U" and "S", their inclusion was waived despite evaluation, leaving data from n = 683 patients for analysis and comparison. RESULTS: During the study period, n = 235 patients (34.4%) had KIG-classification "D". More than 10% were classified as "K" (120 patients, 17.6%), "P" (98 patients, 14.2%), "M" (89 patients, 13.0%), and "E" (81 patients, 11.9%). Of 16 possible classifications with KIG-grade > 3, "D4" was the most common with 26.6% (182 patients). The results confirm the findings from the multicentric DMS•6 from2021 and corresponding KZBV data from 2020. CONCLUSIONS: Sagittal deviations described by classifications "D" and "M" represent with 47.4% almost half of the malocclusions with treatment need. KIG-grade D4 is the most frequent classification. There were no regional deviations of the prevalence of KIG-grades 3-5 in the district of Viersen / North Rhine compared with the national average, not even when scrutinizing a five-year-period.

Prevalence of malocclusions requiring treatment according to the KIG classification : A multipart cross-sectional study over a 20-year period in the district of Viersen/North Rhine.

BACKGROUND AND AIM: In Germany, the reimbursement of orthodontic treatment costs within the framework of the statutory health insurance (GKV) was restricted on 01 January 2002 by the introduction of the orthodontic indication groups (KIG). The aim of this study was to evaluate the prevalence of findings requiring treatment in a specialist practice over a 20-year period. The results were then compared with data from existing older studies. PATIENTS AND METHODS: The distribution of treatment-eligible KIG (KIG classifications grades 3-5) among patients with statutory health insurance in an orthodontic practice in North Rhine was determined over a 20-year period (2002-2021) after the introduction of the KIG system. This period was additionally scrutinized in four 5­year periods according to the operating cycles of the practice. Findings were classified into the highest of 19 possible KIG treatment needs levels. Multiple classifications were not made. RESULTS: Orthodontic treatment was indicated in a total of 4537 (2393 female, 2144 male) patients according to current statutory health insurance guidelines. The KIG classification "D" (increased overjet) was the most frequent within the observed 20 years with 24.3%. Among 11 KIG classifications, 86.1% of the 6 most frequent and 13.9% of the 5 rarest findings were observed constantly over all periods. Of 19 possible indications, "D4" was the most frequent with 19.6%. Of 4537 patients, 20.7% had KIG grade 3, 63.6% KIG grade 4 and 15.7% KIG grade 5. The prevalence of sagittal deviations "D" and "M" was 35.0%, transverse "B" and "K" 17.9% and vertical "O" and "T" 3.7%. Tooth position anomalies "E" and "P" had a share of 24.6%. CONCLUSIONS: The present study confirms existing findings as well as the nationwide data of the National Association of Statutory Health Insurance Dentists (KZBV) from 2020: The sagittal deviations "D" (increased overjet) and "M" (negative overjet) represented the most frequent findings with KIG D4 as the most common classification. The prevalence and age distribution of KIG grades 3-5 requiring treatment corresponded to nationwide comparative data.

Age-dependent prevalence of malocclusions requiring treatment according to the KIG classification : A multipart cross-sectional study over a 10-year period from the district of Viersen/North Rhine.

BACKGROUND AND AIM: Patients with statutory health insurance (SHI) in Germany must undergo an assessment of orthodontic treatment need using the "Kieferorthopädische Indikationsgruppen" (KIG; orthodontic indication groups) classification system since 2002. A treatment need only exists if anomalies of a certain degree of severity are present. The aim of this study was to evaluate the age-dependent prevalence and percentage distribution of KIG grades requiring treatment in patients with SHI before the age of 18 over a 10-year period. PATIENTS AND METHODS: Between 2012 and 2021, treatment indication existed for 1951 (1025 female, 926 male) out of 2288 patients with SHI in the cohort of this study before the age of 18 according to current SHI guidelines. The KIG classification was based on the highest existing KIG grade. There were no multiple classifications. The patient cohort was divided into three patient groups (PG) according to chronological age for analysis: PG 1 < 10 years of age (early treatment), PG 2 10 to < 13 years of age (main treatment) and PG 3 13 to < 18 years of age (late treatment). RESULTS: In PG 1 (454 patients), the KIG classifications D (26.5%), K (25.5%), M (19.4%), and P (18.0%) dominated. In PG 2 (998 patients), classifications D (33.2%), predominated, whereas K (7.5%) and M (5.9%) rarely occurred. The classifications E (12.6%) and P (13.3%) appeared quite frequently. Transverse deviations occurred only about half as often in PG 2 as in PG 1 and PG 3. In PG 3 (499 patients), the classification E (17.6%) was particularly common, while P (2.6%) was rare. The proportion of KIG grades 5 decreased depending on age: 19% in PG 1, 13.5% in PG 2, 10.4% in PG 3. The prevalence of sagittal classifications was highest in all age groups (45.9% in PG 1, 39.1% in PG 2, 31.5% in PG 3). CONCLUSIONS: The distribution of KIG classifications requiring treatment was not homogeneous, but age dependent. The differences were particularly evident in the early treatment group and may be due to the limited applicability of the KIG classification system in patients before late mixed dentition. With increasing age at initial examination, the prevalence of sagittal classifications decreased, while that of vertical classifications increased. Still, the sagittal classifications D and M occurred most frequently in all age groups. The KIG classification D was always the most common in all patients until the age of 18.

Age-dependent interactions of maxillary sutures during RME and their effects on palatal morphology : CBCT and dental cast analysis.

PURPOSE: The effects of rapid maxillary expansion (RME) on the transverse palatine and midfacial sutures have been extensively scrutinized. Unlike the dentition stage, age-dependency was not yet regarded when investigating morphological changes of the tooth-bearing palate. Therefore, the first aim of the present study was to analyse age-dependent sutural and morphological changes of the palate in selected patients by cone-beam computed tomography (CBCT) and dental cast analysis. Secondly, age-dependent effects of RME on width, height, and depth of the palate in the region of the maxillary palatine processes were investigated by a comprehensive dental cast study, so that the combination of results could be used to provide a biomechanical explanation of the occurring changes. METHODS: CBCT datasets of 9 patients (between 7.3 and 13.8 years) were measured around the median palatal suture and compared with the results of an individualised dental cast analysis. In addition, possible effects on other maxillary sutures were investigated. In the dental cast study, changes after RME in the tooth-bearing palate were analysed three-dimensionally in 60 children and adolescents. It was possible to divide those into three equally sized, age-dependant groups (PG1: < 10 years, n = 20; PG2: ≥ 10 < 12 years, n = 20; PG3: ≥ 12 years, n = 20). RESULTS: The CBCT analysis reveals age-related differences in sutural responses. The opening width of the median palatine suture decreases cranially (frontal) and dorsally (horizontal). The opening mode thus changes from parallel to triangular in both planes. The transverse palatine suture completely opens in younger patients only (PG1 and PG2). The width increases are always significant in all patients. While in PG1 the width increase is greater posteriorly than anteriorly, this is always reversed in PG2 and PG3. The palatal height always increases significantly anteriorly, but posteriorly only in the youngest patients (PG 1) median and paramedian. In PG 2 and PG 3, the posterior height change is very small. That is the reason why the anteroposterior comparison reveals a much more pronounced height increase anteriorly than posteriorly. CONCLUSION: The comparison of selected CBCT data with a dental cast analysis allows the conclusion that the maxillary expansion after RME in children up to 10 years is rather parallel, whereas it occurs V­shaped (anterior > posterior transversal, inferior > superior vertical) with increasing age, especially in adolescents from the age of 12. In addition to an age-progressive rigidity of the pterygopalatomaxillary junction, morphological changes of the transverse palatine suture during growth seem to be causal. Thus, age-dependent effects of palatal expansion occur due to a positional change of maxillary centres of rotation and resistance. From dental cast measurements, especially at the skeletal-basal level, conclusions can be drawn about the median palatal suture opening mode.