Treatment effect of bone-anchored maxillary protraction in growing patients compared to controls: a systematic review with meta-analysis

OBJECTIVE

The aim of this systematic review was to determine which evidence level supports maxillary advancement after bone-anchored maxillary protraction (BAMP) in growing patients compared to controls.

SEARCH METHODS

PubMed, Cochrane, Embase, Scopus, and Web-of-Science databases were searched with no restrictions on publication status or year.

SELECTION CRITERIA

Prospective and retrospective human studies about BAMP, in at least three patients, were included. Authors were contacted when necessary, and reference lists of the included studies were screened.

DATA COLLECTION AND ANALYSIS

Two authors undertook independent data extraction with conflict resolution by a third author. Risks of bias were assessed. A meta-analysis for estimates of changes for ANB angle, Wits appraisal, and incisor to mandibular plane angle (IMPA) angle of BAMP treatment compared to control groups was performed.

RESULTS

A total of 449 articles were initially retrieved; 28 full-text articles met the inclusion criteria. Sample sizes ranged from 3 to 52 patients. There was heterogeneity in cephalometric outcomes reported, which prevented the comparison of certain outcomes. ANB angle improved more with BAMP in the maxilla combined with facemask (bone-anchored facemask, BAFM) compared to traditional facemask therapy: this was statistically but not clinically significant (0.2 degrees). No data are available for BAMP with skeletal anchorage in both jaws in combination with Class III elastics (bone-anchored Class III elastics, BAC3E). Likewise, no statistically significant differences in Wits appraisal were found (less than 1 mm). Lower incisor retroclination and facial height seemed to be better controlled with BAC3E compared to BAFM.

CONCLUSIONS

The level of evidence available to support the maxillary advancement effect after BAMP was low. Publications reporting results based on identical samples tended to suggest overly positive results of BAMP. The differences in sagittal correction between BAMP and traditional facemask therapy were small and of questionable clinical significance. Long-term follow-up results are not available and, therefore, much needed.

LIMITATIONS

Most articles had a low level of evidence and some included a historical control group.

REGISTRATION

PROSPERO database number CRD42015023366.

No Need to Routinely Remove Titanium Implants for Maxillofacial Fractures

PURPOSE

Titanium implants are typically used to fix maxillofacial fractures and their routine removal is a controversial topic in maxillofacial surgery. This study aimed to estimate the removal rate and risk factors associated with removal.

MATERIALS AND METHODS

The authors designed and implemented a retrospective study. Adult patients who underwent open reduction and internal fixation with titanium implants for maxillofacial fractures were included and those who returned for implant removal were identified from January 2007 to December 2016. The predictor variables were gender, age, preoperative infection, injury time, trauma cause, and fracture site. The primary outcome variable was removal of titanium implants. Descriptive and bivariate statistics were computed. Kaplan-Meier survival methods were used to estimate rate of removal. Univariate and multivariate Cox proportional hazards models were used to identify risk factors associated with removal.

RESULTS

Of 2,325 patients (1,890 men and 435 women; average age, ∼35.49 yr) registered in this study, 163 (7.01%) had their titanium implants removed and 1-, 2-, and 10-year removal rates were 3, 7, and 8%, respectively. The risk factors most closely associated with removal were preoperative infection, injury by a blow from an object, obsolete fracture, and female gender.

CONCLUSIONS

Routinely removing titanium implants in patients with maxillofacial fracture is not necessary. When the risk factors listed earlier are present in these patients, follow-up should be scheduled more frequently.

Formation of hydroxyapatite on titanium implants in vivo precedes bone-formation during healing

The bone material interface has been an area of intense study over many decades, where studies of the healing process ranging from simple mineral deposition in vitro to actual healing in vivo have given important clues to the importance of calcium minerals in the bone/implant interface. Here, the authors use a combination of in vitro cell culture methods and in vivo implantation to study how the role of the spontaneously formed hydroxyapatite layer on Ti-implants for the in vivo-healing into the bone tissue of rat tibia. Initial experiments were made in reduced systems by incubation of TiO₂ in cell culture medium and analysis by time of flight secondary ion mass spectrometry (ToF-SIMS) and energy-dispersive x-ray spectroscopy followed by subsequent exposure of human embryological stem cells analyzed by von Kossa staining and environmental scanning electron microsopy. In vivo studies of the bone-material interface was analyzed by ToF-SIMS depth profiling using both C₆₀⁺ ions as well as a gas cluster ion source beam, Ar₁₅₀₀⁺ as sputter source. The low ion yield of the Ar₁₅₀₀⁺ for inorganics allowed the inorganic/organic interface of the implant to be studied avoiding the erosion of the inorganic materials caused by the conventional C₆₀⁺ beam.