Lip Bumper Treatment Research Articles

Lip Bumper Therapy Does Not Influence the Sagittal Mandibular Incisor Position in a Retrospective CBCT Study.

Lip bumper (LB) therapy is used as a treatment approach for mild to moderate crowding without extraction of teeth. Previous studies demonstrated that LB increases arch length through molar uprighting and lateral expansion. However, the effects of LB on mandibular incisors are inconclusive. The controversial results from different studies may be due to limitations including absence of a control group and/or use of 2D radiography. To address this issue, the current retrospective longitudinal CBCT study compared a rapid maxillary expansion (RME) group with no lower treatment [16 patients (9 females, 7 males); median age 8.86 years at T1 and 11.82 years at T2] and an RME + LB group [18 patients (13 females, 5 males); median age 9.46 years at T1 and 12.10 years at T2]. The CBCTs taken before and after phase 1 treatment were 3D superimposed based on the mandibular structure and were measured to determine the angular and linear changes of the mandibular incisors over the course of LB treatment. For comparisons between different timepoints within a group, a Wilcoxon matched-pairs signed rank test was used. For intergroup comparisons, a Mann–Whitney U test was used. Both groups showed eruption and protrusion of the mandibular incisors during the observation period, while there was no significant change in proclination of the lower incisors. When comparing the discrepancy of change between groups, there was no statistically significant difference detected. In summary, by utilizing a longitudinal 3D database, the current study demonstrated that the effect of LB on the position of the mandibular incisors is limited.

Perioral muscle activity changes after Lip Bumper treatment.

This prospective non-randomised case-control study analysed lip muscle activity after Lip Bumper (LB) treatment thought surface electromyography. The study group was composed of 40 young patients with a mean age of 10 years and 1 month, treated with LB in the lower arch, while 40 children who did not undergo any treatment, matched for sex and age with the previous sample, constituted the control group. Measurements were performed at the beginning and after 1 year for both groups. Electromyographic recordings were obtained in rest position and during the swallowing of 50 ml of water. In the study group, after 1 year of LB treatment, a statistically significant decrease in values was found; specifically, in upper lip muscle activities at rest position with the appliance in situ (p <0.002) and both with (p <0.001) and without (p <0.001) the appliance for the lower lip. One year of LB treatment significantly reduced lip muscle activities at both rest position and during swallowing compared with the untreated sample. These results indicated a potential short-term of upper and lower lip muscle adaptation to the new balance induced by LB treatment.

6 下顎リップバンパー治療における歯列の変化と下顎運動との関連について(第475回 大阪歯科学会例会)

6 下顎リップバンパー治療における歯列の変化と下顎運動との関連について(第475回 大阪歯科学会例会)

Predictors of postretention stability of mandibular dental arch dimensions in patients treated with a lip bumper during mixed dentition followed by fixed appliances.

To identify which dental and/or cephalometric variables were predictors of postretention mandibular dental arch stability in patients who underwent treatment with transpalatal arch and lip bumper during mixed dentition followed by full fixed appliances in the permanent dentition. Thirty-one patients were divided into stable and relapse groups based on the postretention presence or absence of relapse. Intercuspid, interpremolar, and intermolar widths; arch length and perimeter; crowding; and lower incisor proclination were evaluated before treatment (T0), after lip bumper treatment (T1), after fixed appliance treatment (T2), and a minimum of 3 years after removal of the full fixed appliance (T3). Logistic regression analyses were performed to evaluate the effect of changes between T0 and T1, as predictive variables, on the occurrence of relapse at T3. The model explained 53.5 % of the variance in treatment stability and correctly classified 80.6 % of the sample. Of the seven prediction variables, intermolar and interpremolar changes between T0 and T1 (P = .024 and P = .034, respectively) were statistically significant. For every millimeter of increase in intermolar and interpremolar widths there was a 1.52 and 2.70 times increase, respectively, in the odds of having stability. There was also weak evidence for the effect of sex (P = .047). The best predictors of an average 4-year postretention mandibular dental arch stability after treatment with a lip bumper followed by full fixed appliances were intermolar and interpremolar width increases during lip bumper therapy. The amount of relapse in this crowding could be considered clinically irrelevant.

Short- and long-term evaluation of mandibular dental arch dimensional changes in patients treated with a lip bumper during mixed dentition followed by fixed appliances.

To evaluate short- and long-term mandibular dental arch changes in patients treated with a lip bumper during the mixed dentition followed by fixed appliances, compared with a matched control sample. Dental casts and lateral cephalograms obtained from 31 consecutively treated patients before (T0) and after (T1) lip bumper, after fixed appliances (T2), and a minimum of 3 years after fixed appliances (T3) were analyzed. The control group was matched as closely as possible. Arch width, arch perimeter, arch length, and incisor proclination were evaluated. Repeated measures ANOVA was used to analyze changes in measurements over all four time points between treatment and control groups. Arch widths and crowding were always significantly different except at T2-T1. At T1-T0, only crowding decreased 3.2 mm while intercanine, interpremolar, and intermolar widths increased by 3.8, 3.3, and 3.9 mm, respectively. Changes at T3-T2 showed a significant decrease of 2.1 mm for crowding and an increase of 3.5, 2.9, 2.7, and 0.8 mm for intercanine, interpremolar, and intermolar widths and arch perimeter, respectively. Finally, at T3-T0, the reduction in crowding of 5.03 mm was significant and clinically important in the treated group. The differences between intercanine, interpremolar, and intermolar widths were also significant (2.1, 3.8, and 3.6 mm, respectively). All those differences favored the treated group. Mandibular dental arch dimensions were significantly changed after lip bumper treatment. At follow-up, all arch widths were slightly decreased, generating an increase of 0.4 mm in crowding, considered clinically irrelevant. Overall changes remained stable after an average 6.3-year follow-up.

Mandibular lip bumper treatment and second molar eruption disturbances

Mandibular lip-bumper (LB) nonextraction treatment, usually started before complete second molar (M2) eruption, inevitably interacts with the development of the dentition. Yet, its effects on M2 eruption are still unknown. The first aim of this study was to retrospectively investigate whether LB therapy (260 patients) enhances the risk for M2 ectopic eruptions and impactions in comparison with 135 untreated subjects. The second aim was to assess, among treated patients (n = 197), the main potential determinants of M2 impaction and ectopic eruption. M2 eruption and impaction were determined on panoramic radiographs. To assess the predictive role of M2 inclination in relation to the first molar, a panoramic radiograph suitable for this measurement before treatment was required. The data were analyzed by using software (version 8.2, SAS, Cary, NC). LB treatment significantly enhanced M2 impaction and ectopic eruption. Negative prognostic factors were found. An initial inclination of the M2 greater than 30° was significantly associated with a higher impaction risk compared with an angulation less than 10°. LB treatment duration longer than 2 years increased the risk of ectopic eruptions. While gaining space in the anterior arch, unwanted effects might be produced in the posterior arch. To be informed about these unplanned events is necessary to better optimize treatment.

Long-term stability of lip bumper therapy followed by fixed appliances.

Lip bumper treatment has been shown to successfully increase arch width, procline the incisors, and distalize molars. However, few studies have been performed showing the long-term stability of lip bumper treatment. In this study, mandibular casts taken by a single practitioner from 51 patients treated with lip bumpers without rapid palatal expansion were analyzed at pretreatment, post-lip bumper treatment, posttreatment, and long-term out of treatment. Measurements of arch width, arch depth, arch length, and anterior crowding were made. During treatment, there was a mean decrease in irregularity of 3.73 mm, with a posttreatment increase of 0.76 mm, for a net decrease of 2.97 mm. Despite posttreatment decreases, significant gains in arch width were maintained for extended periods of time. The intercanine width had a net increase of 1.78 mm (19% relapse), first premolars 3.39 mm (26% relapse), second premolars 2.58 mm (34% relapse), and first molars 2.17 mm (20% relapse). Lip bumper treatment along with fixed appliances is an effective means to obtain long-term increases in arch width and decreases in the irregularity index.

Relationship between dental changes and mandibular movement caused by lip bumper treatment

Relationship between dental changes and mandibular movement caused by lip bumper treatment

Muscle activity with the mandibular lip bumper

This prospective study was designed to measure muscle activity with lip bumper treatment. Surface electromyography was used to measure upper and lower lip activity with and without the appliance in place. Measurements were taken on a sample of 25 adolescent patients (age range, 10 to 17 years) before and after 12 months of lip bumper treatment. Recordings included a closed lip rest position, swallowing of water, and speech of the words “church,” “phone,” and “pop.” Insertion of the lip bumper at the pretreatment recording resulted in significantly increased activity of the upper and lower lips at rest ( P < .001) and while swallowing ( P < .05), whereas the response for speech was variable. Pretreatment and posttreatment muscle activity measurements of the lower lip were compared to determine whether 12 months of treatment with the appliance resulted in muscle adaptation. The initial increase of muscle activity with insertion of the appliance for the closed lip rest position and for swallowing was not followed by a decrease during the treatment period. There were significant differences in muscle activity when comparing the “new” equilibrium introduced by the lip bumper to the “old” pretreatment equilibrium without the appliance. Although it was shown that the insertion of the appliance had a significant influence on muscle activity of the lips, the results of this study did not indicate adaptation of the lower lip to the appliance over the treatment period. (Am J Orthod Dentofacial Orthop 2000;117:384-90)

Perioral forces and dental changes resulting from mandibular lip bumper treatment

This prospective study compares pretreatment and posttreatment forces produced by a lip bumper on the mandibular first molars and determines the dental effects of this appliance after 1 year of treatment. Twenty-five patients, ages 10 to 17 years, received fixed 0.045-inch passive stainless steel lip bumpers positioned at the level of the gingival margin, 2 mm from the labial surface of the teeth as the only form of treatment in the mandibular arch. At the end of 1 year, cephalometric radiographs and dental casts were taken, and lower lip forces remeasured during rest, speech, and swallowing. Lip force measurements were performed using specially designed strain gauges mounted bilaterally in the lip bumper tubes. Measurements of lip forces made before and after treatment were compared to explore the changes, if any, due to muscle adaptation to the appliance. Dental changes were measured from casts and cephalometric radiographs. Correlation analyses were performed to determine whether a relationship existed between initial force levels and resulting tooth movement. Pretreatment and posttreatment forces did not demonstrate a statistically significant difference. On the other hand, measurement of the dental casts revealed a significant increase in arch length caused by incisor proclination and protrusion, combined with molar distalization. The arch width significantly increased at the canines, first and second premolars, and first molars. The amount of force exerted by the lower lip on the molars was not correlated to the degree of tooth movement recorded in this sample. (Am J Orthod Dentofacial Orthop 1998;113:247-55.)

The effect of a lip bumper on lower dental arch dimensions and tooth positions.

The effect of a lip bumper on the dimensions of the lower dental arch and on the inclination of the incisors and first molars was studied in 40 children, aged 9-12 years. The children wore their lip bumper full time for 7-10 months. The effects of the lip bumper therapy were recorded on dental casts and profile cephalograms made before and after the treatment. The positions and stages of development of the lower second molars were determined on pretreatment intra-oral radiographs. The lip bumper treatment resulted in an increase of the dental arch widths between the molars, premolars, and canines. The arch length increased through proclination of the incisors and uprighting of the first molars. The stages of development and the positions of the second molars had no influence on the effect of the treatment. Simultaneous treatment in the maxilla with a headgear, a transpalatal arch or a removable plate had no influence on the outcome of the lip bumper therapy.

Mandibular arch perimeter changes with lip bumper treatment

The effects of lip bumper treatment on the mandibular arch were observed in 32 patients with late transitional and early permanent dentitions. Dental cast measurements were made for arch perimeter, arch length, and arch width. Cephalometric radiographs were used to determine labial tipping of the incisors and distal movement of the molars. Arch circumference increased in all patients, ranging from 0.7 mm to 8.8 mm, with an average of 4.1 mm. The mean increase in arch length was 1.2 mm and was largely attributed to anterior tipping of the mandibular incisors. Change in arch length was the most predictive variable for the increase in arch circumference. Passive changes in arch width were recorded, with a mean increase of 2.0 mm in the intercanine distance and 2.5 mm in the first premolar distance. Arch width increments contributed to the increase in arch circumference, but the increases in arch width were not found to be predictive of the change in arch circumference. Changes in either arch circumference or arch length were not related to the duration of treatment, age and sex of the patient, or the eruption status of the permanent second molars.