Tooth-borne versus bone-borne rapid maxillary expansion for transverse maxillary deficiency: A systematic review

PURPOSE

The aim of this study was to compare dentoskeletal effects of bone-borne expanders with those of conventional expanders in adolescent and adults having transverse maxillary deficiency.

METHODS

All randomized clinical trials (RCTs) comparing the effects of bone-borne with those of tooth-borne expansion for treatment of maxillary transverse deficiency in adults and adolescents with maxillary transverse deficiency or posterior crossbite were included. The systematic search was irrespective of language and publication type. The electronic search was conducted from 1980 to January 2018.

RESULTS

The electronic searches retrieved 713 references after screening for eligibility criteria. Eight studies met the inclusion criteria for this systematic review involving 289 participants. Four studies compared rapid maxillary expansion (RME) between bone-borne and tooth-borne devices and indicated effectiveness of both devices on maxillary expansion. In the first molar region, there was no significant difference between two devices in either skeletal or dental expansion. Two studies compared the effects of bone-borne and tooth-borne device following SARME and suggested no significant difference regarding amount and pattern of expansion at various levels and in molar and premolar region between two groups. Two studies compared bone-borne and tooth-bone-borne devices.

CONCLUSION

Within the limit of the present evidence regarding maxillary expansion, it seems that both tooth-borne and bone-borne devices result in the same outcome in terms of the amount of maxillary expansion, dental tipping, stability and perceived pain both in RME and SARME procedure. PROSPERO registration: CRD42017061078.

Morphology of maxilla in patients with palatally displaced canines

OBJECTIVES

The aim of this study was to investigate the possible relationship between the morphology of maxilla and the palatally displaced canines (PDC).

MATERIALS AND METHODS

In this cross-sectional study, there were 101 patients (45 males, 56 females) aged 12 to 16years, referred to Hamadan school of dentistry in 2014. They were divided into 3 groups: the bilateral PDC (PDCb) group (male=15, female=21), the unilateral PDC (PDCu) group (male=16, female=19), and the control group (male=14, female=16). Five morphology related variables including intermolar width, maxillary arch length, palatal vault depth, palatal intermolar area, and nasal width were measured using CBCT images with Dolphin Imaging software, version 11.5. Statistical analysis was performed with ANOVA and the Dunnett test using SPSS software, version 16.0.

RESULTS

Only the palatal intermolar area and the palatal vault depth values were significantly less in the PDCu and the PDCb groups than those in the control group (the palatal intermolar area: 376.17, 381.93, and 423.75mm², the palatal vault depth: 13.19, 13.42, and 14.59mm; respectively; P<0.05). For all the variables, there was no statistically significant difference between the PDCu and PDCb groups.

CONCLUSION

Decreased palatal vault depth and palatal intermolar area may be correlated with greater chance of palatal displacement of canines. Future prospective studies in mixed dentition patients are needed as a predictive factor to find the probability of PDC.

Effect of different types of dental anchorage following first premolar extraction on mandibular third molar angulation

OBJECTIVES

The aim of this study was to determine the effect of first premolar extraction with different anchorages as well as non-extraction on mandibular third molar angulation.

MATERIALS AND METHODS

The pretreatment (T1) and posttreatment (T2) panoramic radiographs of one hundred patients from Hamadan (Iran), who underwent fixed orthodontic treatment were investigated and the angle between long axis of right mandibular third molars and a constructed horizontal plan (HRP) was measured. The sample was equally divided into four groups including first premolar extraction with maximum anchorage, that with moderate anchorage, that with minimum anchorage and non-extraction group.

RESULTS

In the first premolar extraction groups with moderate and minimum anchorages, third molar angulation increased (8.12 and 7.48°, respectively) significantly from T1 to T2 (P=0.001 and 0.003, respectively), but in the first premolar extraction group with maximum anchorage and non-extraction group, increase in third molar angulation (2.84 and 0.8°, respectively) was not statistically significant (P=0.082 and 0.943, respectively). Third molar uprighting was significantly different among four groups using one-way ANOVA (P=0.004). Tukey (HSD: honestly significant difference) post hoc test indicated that difference in third molar angulation was statistically significant between first premolar extraction group with moderate anchorage and non-extraction group (P=0.007) and also between the first premolar extraction group with minimum anchorage and non-extraction group (P=0.024).

CONCLUSION

The first premolar extraction groups with moderate and minimum anchorage may lead to more chance of third molar eruption and this can be helpful in borderline cases to consider third molar angulation as one of determining indicators to decide whether to extract or not to extract first premolars.