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.

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.

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.

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.

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.

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.

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.

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.

Ultra short time to Echo (UTE) MRI for cephalometric analysis-Potential of an x-ray free fast cephalometric projection technique.

OBJECTIVES: A novel magnetic resonance imaging (MRI) scan protocol is presented on the basis of ultra-short time to echo (UTE). By this MRI cephalometric projections (MCPs) can be acquired without the need of post processing in one shot. Different technical parameterizations of the protocol are performed. Their impact on the performance of MCPs is evaluated in comparison to the gold standard-the lateral cephalometric radiography (LCR) for cephalometric analysis (CA) in orthodontics. METHODS: Seven MCPs with various scan parameters influencing the scan duration and one LCR are used from one subject. 40 expert assessors performed CA for 14 predefined cephalometric landmarks. Relative metric distances and absolute angular measurements were calculated. Statistical analysis is presented and the deviations are highlighted to demonstrate the potential of the method for further analysis. RESULTS: The MCPs are acquired in 5-154 seconds, depending on resolution and contrast. Mean relative distances were 2.4-2.7 mm in MCPs and 1.6 mm in LCR, which demonstrate the accuracy and level of agreement of the expert assessors in identifying anatomical landmarks. In comparison to other studies, the presented MCP performed similar in angular analysis and demonstrated on average deviation of 1.2° ±1.1° in comparison to LCR. Despite the point articulare (Ar) and the related gonial angle the calculate distances and angles show outcomes in the range of ±2°/2mm. CONCLUSIONS: MCPs can be acquired much faster in comparison to other techniques known from literature for CA. This study demonstrated the potential of the new method and showed first feasible results. Further research is needed to analyze the performance on a broad range of patients.

Efficiency of the skeletonized Pendulum K appliance for non-compliance maxillary molar distalization : A clinical pilot study.

PURPOSE: Conventional anchorage with exclusively intraorally anchored appliances for non-compliance molar distalization combines a palatal acrylic button with periodontal anchorage. This type of anchorage is critically discussed because of the temporary hygienic impairment of the palate and the uncertain anchoring quality of the button. A purely dentally/periodontally anchored Pendulum K appliance was developed, which is exclusively anchored via four occlusal rests. The aims of this pilot study were to examine the suitability of the skeletonized Pendulum K for distalization of maxillary molars, and to investigate the quality of this alternative anchoring modality. PATIENTS AND METHODS: In all, 10 patients received skeletonized Pendulum K appliances attached to all maxillary premolars for bilateral molar distalization. Supporting anchorage through an acrylic button adjacent to the anterior palate was not used. The pendulum springs were initially activated on both sides with a distalization force of 220 cN each and provided with uprighting and toe-in bends. The specific force/moment system was regularly reactivated intraorally by adjustment of the distal screw. RESULTS: The study demonstrates the suitability of the skeletonized Pendulum K appliance for the distalization of maxillary molars (3.28 ± 0.73 mm). Side effects on the molars were slight distal tipping (3.50 ± 2.51°/PP, 3.00 ± 1.41°/SN) and mesial inward rotation (average 2.75 ± 7.50° and 4.50 ± 12.77°). Significant anchorage loss occurred in the form of mesialization of the incisors by 1.40 ± 0.82 mm and of the first premolars by 2.28 ± 0.85 mm. CONCLUSION: The skeletonized Pendulum K appliance allows compliance-free upper molar distalization. Exclusively dental/periodontal anchorage resulted in a lower percentage of molar distalization compared to a conventional anchoring preparation of the Pendulum K with a palatal acrylic button. Anchorage loss had a comparatively stronger effect on the anchoring premolars but less on the incisors. Typical side effects on the molars such as distal tipping and mesial inward rotation were remarkably low.

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.

Occlusal height difference between maxillary central and lateral incisors: should aesthetic perception influence bracket placement?

BACKGROUND: The aim of this study was to verify anecdotal evidence that the maxillary central-to-lateral occlusal height difference (OHD) of more than 0.5 mm is a feature displayed in the majority of media and to discuss its implications for individualized orthodontic treatment planning. METHODS: Photographs of smiling female models were collected from a variety of printed advertisements and allocated to 3 groups (n = 30 each): 1 dental, 2 fashion and 3 orthodontics. Group 4 used female patient images from orthodontic textbooks, assuming an OHD of 0.5 mm between maxillary central and lateral incisors. OHD was assessed by measuring the incisor height on the photographs and using average values to establish height differences. RESULTS: The average maxillary central-to-lateral incisor OHD differences were 1.39 mm (dental literature), 1.34 mm (fashion advertisements), 1.23 mm (orthodontics) and 0.62 mm (orthodontic textbooks) respectively. The differences between the advertisement groups were not significant (P >  0.05), but for orthodontic textbooks they were (P <  0.001). CONCLUSIONS: Advertisers seem to prefer greater maxillary central-to-lateral OHD compared to commonly used bracket placement protocols. Therefore, discussing OHD at start of treatment is recommended; modification of commonly used bracket placement protocols may be helpful to achieve desired aesthetic outcome.

Are morphologic and topographic alterations of the mandibular fossa after fixed functional treatment detectable on tomograms? Visual classification and morphometric analysis.

AIM: The goal was to evaluate if changes in morphology and topography of the mandibular fossa after Functional Mandibular Advancer (FMA) treatment are detectable on tomograms. Furthermore, the suitability of digital tomograms (DT) over magnetic resonance imaging (MRI) for this particular question was investigated. MATERIALS AND METHODS: In all, 25 patients (14 female, 11 male) with a skeletal class II malocclusion received treatment with a FMA. DTs were available prior to (T1) and after (T2) FMA treatment. A total of 50 temporomandibular joints were investigated. The mandibular fossae were evaluated metrically and visually regarding treatment-induced alterations. A p < 0.05 was set as the level for statistical significance for all tests. Results were compared to the results of a recent MRI study. RESULTS: Visual inspection of all 50 joints in the DT at T1 and T2 revealed no alterations of the fossa shape in the sagittal plane; 24 patients showed identical morphology of right and left joints. The metrical analysis revealed no significant changes regarding width, depth and ratio thereof between T1 and T2. There also were no bilateral differences. Another 18 different distance measurements between porion, mandibular fossa, articular eminence and pterygoid fossa showed no significant changes. There was no detectable proof of a fossa shift. CONCLUSIONS: No changes in the sagittal plane, mandibular fossa, the articular tubercle, or a possible fossa shift were found in the DT of class II patients after FMA treatment. DT and MRI measurements and the visual inspection revealed identical findings; thus, DT appears to be a valuable research tool for sagittal analysis of mandibular fossa changes.

Mandibular fossa morphology during therapy with a fixed functional orthodontic appliance : A magnetic resonance imaging study.

OBJECTIVE: During therapy of distoclusion entailing a rigid, fixed orthodontic appliance, the mandibular fossa and condyle are ideally remodeled, while dentoalveolar effects occur through adaptive mechanisms. Adaptive processes, especially in the fossa region, have not been adequately investigated. Our magnetic resonance imaging (MRI) investigation aimed to assess the effects of therapy with a functional mandibular advancer (FMA) on mandibular fossa morphology. PATIENTS AND METHODS: We monitored via MRI the therapeutic course of 25 patients at three time points. Visual findings and metric assessments were carried out in the sagittal plane. Three-dimensional (3D) reconstructions of the joint structure of two exemplary patients were also made. RESULTS: Visual examinations of the MRI slices at the three time points revealed no changes in fossa shape in any of the 50 temporomandibular joints. Lateral comparisons showed that the morphology of the fossae of all 25 patients was identical. Metric analysis demonstrated no significant alterations in width, depth, or in their ratio, not even laterally. Nine measurements of the distances between the porion, mandibular fossa, and articular eminence revealed no significant changes in total or on the left and right sides, or intralaterally. CONCLUSION: The visual findings and metric analyses of parasagittal MRI slices did not indicate any morphological changes in the mandibular fossa or articular eminence in patients with distoclusion treated via a rigid, fixed orthodontic appliance. However, special reworking of the MRI data facilitated reconstruction of the surfaces of joint structures in 3D. This new method makes it possible to depict more accurately and noninvasively the adaptive mechanisms not ascertainable via metric methods and to assess them as 3D structures.

Insertion torque values and success rates for paramedian insertion of orthodontic mini-implants : A retrospective study.

OBJECTIVES: Orthodontic mini-implants (OMIs) are a reliable method to provide temporary orthodontic anchorage. We hypothesized that there is an optimal insertion torque (<10 Ncm) that can be used to ensure the success of self-drilling OMIs in the paramedian region. PATIENTS AND METHODS: Included were 40 (26 females, 14 males) consecutive patients requiring palatal skeletal anchorage. Mean age was 17.3 years (range 11.0-44.6 years) for female patients and 15.7 years (range 10.6-36.9 years) for male patients. A total of 22 patients received a Beneslider according to Wilmes for the distalization of maxillary first molars, 10 patients received a Mesialslider for the mesialization of maxillary first molars, and 8 patients received a bone-borne rapid palatal expansion (RPE) appliance. Torque values of 10-15 Ncm were recorded in 46.3% of the OMIs and 15-20 Ncm in 35% of OMIs. OMIs that endured the orthodontic force applied for ≥6 months were considered as success. RESULTS: The overall success rate was 98.8%. No significant differences were found between insertion torque values with respect to the right and left sides, Jarabak's ratio, facial axis, and Frankfort to mandibular plane angle. There were no significant differences in the OMIs insertion torques with regard to the different appliances. No association was found between insertion torque and vertical skeletal morphology. CONCLUSION: With an overall success rate of 98.8%, the study hypothesis that greater insertion torque (>10 Ncm) will decrease the success rate and increase palatal OMI failure was rejected.

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.

Influence of interradicular and palatal placement of orthodontic mini-implants on the success (survival) rate.

BACKGROUND: The purpose of this retrospective cohort study was to investigate the success rates of orthodontic mini-implants (OMIs) placed in different insertion sites and to analyse patient and site- related factors that influence mini-implant survival. METHODS: Three hundred eighty-seven OMIs were inserted in 239 patients for orthodontic anchorage and were loaded with a force greater than 2 N. Two different insertion sites were compared: 1. buccal inter-radicular and 2. palatal, at the level of the third palatal ruga. Survival was analysed for location and select patient parameters (age, gender and oral hygiene). The level of statistical significance was set at p < 0.05. RESULTS: The overall success rate was 89.1%. There were statistically significant differences between insertion sites; success rate was 98.4% for OMIs placed in the anterior palate and 71% for OMIs inserted buccal between roots (p < 0.001). CONCLUSIONS: Success rate of OMIs was primarily affected by the insertion site. The anterior palate was a more successful location compared to buccal alveolar bone.

Effects of combined orthodontic-orthognathic treatment for class II and III correction on posterior airway space : Comparison of mono- and bignathic osteotomies.

OBJECTIVES: Comparison of treatment effects on the posterior airway space (PAS) in patients treated with combined orthodontic-orthognathic surgical treatment. METHODS: Pre- and postsurgical lateral cephalograms of 53 (34 females, 19 males) Caucasian patients were analyzed using a customized set of measurements. According to malocclusion (Class II or III) and surgical approach (either monognathic or bignathic), patients were allocated into four groups. PAS was assessed from cranial to caudal at six levels (P1-P6). 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: In patients treated for Class II malocclusion, PAS retropalatally (P1 level) almost remained unchanged, whereas measurements at levels P2-P6 showed a mean increase ranging from approximately 2-5.5 mm. Significant changes were most pronounced in monognathic Class II patients (group 1) at levels P2-P4 with mean values ranging from approximately 3.7-5.5 mm. In patients treated for Class III malocclusion (groups 3 and 4), measurements at the P1 level almost remained unchanged in patients who underwent mandibular setback surgery (group 3), whereas the same measurements exhibited significant increase (>6 mm) in patients treated with bignathic surgery (group 4). CONCLUSIONS: Bignathic surgery led to smaller changes of pharyngeal depth in Class II and III patients than monognathic surgery. Alterations of the PAS due to orthognathic surgery should be considered during orthodontic and presurgical treatment planning.