Gingival recessions of lower incisors after proclination by orthodontics alone or in combination with anterior mandibular alveolar process distraction osteogenesis

OBJECTIVES

The aim of this study was to longitudinally compare periodontal conditions in consecutive patients who had orthodontic treatment with proclination of lower incisors either by orthodontics alone or in combination with anterior mandibular alveolar process distraction osteogenesis (DO).

MATERIALS AND METHODS

Nineteen patients had orthodontic treatment with DO, 18 with extraction of lower premolars (Ex), and 18 without extractions (Nonex). Lateral cephalograms were used to evaluate lower incisor proclination, while study casts and intraoral photographs were used to evaluate labial and lingual gingival recessions before (T1) and at an average of 4.5 years (T2) after treatment.

RESULTS

No differences in labial recessions on lower incisors were present between the patient groups despite greater lower incisor proclination in the Nonex and DO groups. The Ex group showed no new development of lingual recessions in contrast to the Nonex (eight sites; two subjects) and DO groups (seven sites; three subjects). Severe lingual recessions (increased ≥1 mm) were more present in the Nonex group (five sites; two subjects) compared to the Ex group (no sites). Proclination of lower incisors of 10° or more either by orthodontic tooth movement or displacement of the whole alveolar process increased the risk of lingual gingival recessions 17 times. This was not the case with labial gingival recessions.

CONCLUSIONS

Orthodontic or surgical proclination of lower incisors beyond a 10° limit increases the risk of inducing lingual gingival recessions.

CLINICAL RELEVANCE

During orthodontic treatment, with or without DO, one should avoid proclining lower incisors more than 10° to decrease the risk of gingival recessions.

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Albino Triaca a été chef de clinique au centre de chirurgie maxillo-faciale et d’esthétique de San Marin. Il est également depuis un an professeur du service de chirurgie maxillo-faciale de Salzbourg, où il dirige plus spécifiquement le service de la chirurgie du nez. Il exerce depuis plus de 30 ans à la Klinik Pyramide au bord du lac de Zurich où il me reçoit pour cet entretien.

Neurosensory and functional evaluation in distraction osteogenesis of the anterior mandibular alveolar process

Neurosensory status and craniomandibular function of 19 patients (mean age 35.2 years, range 17.8-58.8 years) treated by combined surgical orthodontic treatment with distraction osteogenesis of the mandibular anterior alveolar process (DO group) was compared with that in 41 orthodontically treated patients (mean age 22.9 years, range 15.1-49.0 years; control group). Clinical examination took place on average 5.9 years (DO group) and 5.4 years (control group) after treatment ended. Neurosensory status was determined by two-point discrimination (2-pd) and the pointed and blunt test. Lateral cephalograms evaluated advancement of the mandibular alveolar process and possible relapse. There was no significant difference in craniomandibular function and neurosensory status between the groups. Age was significantly correlated with 2-pd at the lips (DO: p=0.01, R=0.575; control group: p=0.039, R=0.324) and chin (DO: p=0.029, R=0.501; control group: p=0.008, R=0.410). Younger patients had smaller 2-pd values. Gender, age, the amount of advancement, and relapse at point B or incision inferior show no correlation with craniomandibular function and neurosensory impairment. DO of the mandibular anterior alveolar process is a valuable and safe method with minor side effects regarding neurosensory impairment.

Unconventional implants for distal cantilever fixed full-arch prostheses: a long-term evaluation of four cases

Excessive cantilever lengths of fixed implant-supported prostheses may have functional and biomechanical disadvantages. This study reports the clinical outcomes of unconventional implants placed for distal support of a fixed implant-supported prostheses. Seven extraoral implants with intraosseous lengths of 2.5 to 4.0 mm were placed in four patients. Distal cantilevers had a mean length of 29.8 mm (range, 18.6 to 39.3 mm). No bone loss or other adverse events were found. The prosthetic plan was maintained in all patients. Within the limits of the employed research design, this concept seems to be a successful option for fixed complete implant-supported prosthesis treatment.

Skeletal and dental stability of segmental distraction of the anterior mandibular alveolar process. A 2-year follow-up

33 patients (27 females; 6 males) were retrospectively analysed for skeletal and dental relapse before distraction osteogenesis (DOG) of the mandibular anterior alveolar process at T1 (17.0 days), after DOG at T2 (mean 6.5 days), at T3 (mean 24.4 days), and at T4 (mean 2.0 years). Lateral cephalograms were traced by hand, digitized, superimposed, and evaluated. Skeletal correction (T3-T1) was mainly achieved through the distraction of the anterior alveolar segment in a rotational manner where the incisors were more proclined. The horizontal backward relapse (T4-T3) measured -0.8mm or 19.0% at point B (p<0.001) and -1.6mm or 25.0% at incision inferior (p<0.001). Age, gender, amount and type (rotational versus translational) of advancement were not correlated with the amount of relapse. High angle patients (NL/ML'; p<0.01) and patients with large gonial angle (p<0.05) showed significantly smaller relapse rates at point B. Overcorrection of the overjet achieved by the distraction was seen in a third of the patients and could be a reason for relapse. Considering the amount of skeletal relapse the DOG could be an alternative to bilateral sagittal split osteotomy for mandibular advancement in selected cases.

Soft tissue stability in segmental distraction of the anterior mandibular alveolar process. A 2-year follow-up

This study evaluated soft tissue changes in adult patients treated with distraction osteogenesis (DOG) of the anterior mandibular alveolar process and related it to different parameters. 33 patients (27 females; 6 males) were analysed retrospectively before surgery at T1 (17.0 days), after surgery at T2 (mean 6.5 days), at T3 (mean 24.4 days), and at T4 (mean 2.0 years). Lateral cephalograms were traced by hand, digitized, superimposed, and evaluated. Statistical analysis was carried out using Kolmogorov-Smirnov test, paired t test, Pearson's correlation coefficient, and linear backward regression analysis. 2 years postoperatively (T4), the net effect of the soft tissue at point B' was 100% of the advancement at point B whilst the lower lip (labrale inferior) followed the advancement of incision inferior to 46%. Increased preoperative age was correlated (p<0.05) with more horizontal backward movement (T4-T3) for labrale superior and pogonion'. Higher NL/ML' angles were significantly correlated (p<0.05) with smaller horizontal soft tissue change at point B'. Gender and the amount of skeletal and dental advancement were not correlated with postoperative soft tissue changes (T4-T3). DOG of the anterior mandibular alveolar process is a valuable alternative for mandibular advancement regarding soft tissue change and predictability.

The use of extraoral implants for distal-extension removable dentures: a clinical evaluation up to 8 years

PURPOSE

This retrospective study reports the clinical outcome following placement of extraoral implants in severely resorbed posterior ridges to support distal-extension removable dentures.

MATERIAL AND METHODS

Consecutively treated patients with partially or completely edentulous ridges, with available bone height in the posterior region of 6 mm or less, were included in the study. Implants originally intended for extraoral use (Straumann) were placed in second molar regions and allowed to heal for 4 to 6 months before abutment connection. At recall appointments, the peri-implant hard and soft tissues were evaluated. Complications with implant components, as well as mechanical and structural failures of the prostheses, were recorded. Two-year survival rates were calculated and life table analyses undertaken.

RESULTS

Twenty-nine patients (19 women and 10 men; average age 61.2 years, range, 44 to 75 years) were included in the study. Forty-seven extraoral implants in 26 patients were placed in the second molar site of the mandible. Two extraoral implants in 2 patients failed during the osseointegration phase, yielding an 8-year cumulative success rate of 91.8%. The mean distance from the extraoral implants to the most distal tooth/implant was 28.1 mm (range, 16.7 to 39.2 mm). Twenty-three extraoral implants were restored with magnets, 18 with ball anchors, and 4 with conical cylinders. Replacement of abutments and retention elements was necessary in 2 patients. Four abutments in 2 patients were disconnected from the restorations.

CONCLUSIONS

Within the limits of the employed research design, extraoral implants may be used successfully to provide support for distal-extension removable dentures in severely resorbed posterior alveolar ridges.

Segmental distraction osteogenesis of the anterior mandible for improving facial esthetics. Preliminary results

AIM

To report preliminary results of treatment with gradual repositioning of the anterior mandibular segment using distraction osteogenesis in patients with anterior tooth crowding and/or an unfavorable anteroposterior relationship between the anterior dentoalveolar area and the skeletal base.

METHODS

The following outcome measures were considered: ability of the technique to achieve the desired skeletal jaw position, resolution of the crowding, periodontal condition (recessions and probing pocket depths), temporomandibular joint symptoms, tooth sensitivity, permanent nerve injury, additional complications, and patient satisfaction. Four patients were treated.

RESULTS

All outcome measures indicated that the therapy goal was achieved and the results maintained to date. Periodontal conditions were slightly improved. Two patients were very satisfied; 2 were only partially satisfied with the therapy. In 1 patient the root of the mandibular right first premolar was damaged during the vertical osteotomy procedure and the mandibular right central incisor did not respond to the postoperative sensitivity test. Another patient reported tension at the temporomandibular joint when chewing hard food.

CONCLUSION

The preliminary results are encouraging. However, larger trials are needed to acquire sufficient knowledge of the efficacy, predictability, and ideal indications for the mandibular osteodistraction technique.

Treatment of mandibular retrusion by distraction osteogenesis: a new technique

We treated the mandibular retrusion of a 20-year-old man by distraction osteogenesis. Our aim was to avoid any visible discontinuities in the soft tissue profile that may result from conventional "one-step" genioplasty. The result was excellent. In addition to a good aesthetic outcome, there was increased bone formation not only between the two surfaces of the osteotomy but also adjacent to the distraction zone, resulting in improved coverage of the roots of the lower incisors. Only a few patients have been treated so far, but the method seems to hold promise for the treatment of extreme retrognathism, as these patients often have insufficient buccal bone coverage.

Periosteoplasty for soft tissue closure and augmentation in preprosthetic surgery: a surgical report

Soft tissue closure is a critical factor in preprosthetic surgery and implant placement. In large transverse or vertical bone augmentations, there is often insufficient or very thin mucosa available. Soft tissue dehiscences and bone or implant exposure may result. Based on the application of a periosteal flap, the presented method solves this problem. The flap is prepared in the neighboring area and folded into the corresponding surgical area. It not only provides good soft tissue coverage but also results in soft tissue augmentation. Periosteoplasty has been successfully applied in over 60 patients over the last 2 years.

Segmental distraction osteogenesis of the anterior alveolar process

PURPOSE

This article describes a nonextraction therapy for patients with anterior tooth crowding in the mandible or with an unfavorable relation between the anterior dentoalveolar area and the skeletal base. The method involves the gradual repositioning of the dentate segment by use of distraction osteogenesis.

PATIENTS AND METHODS

The method was applied in 25 patients. Indications comprised skeletal Class II patients with crowding, Class I patients with crowding, and Class III patients requiring decompensation before orthognathic surgery. A special hinge-joint bone plate was developed to allow the rotation of the anterior bone segment into the desired position. The gradual repositioning was achieved with orthodontic appliances.

RESULTS

The procedure was successful in all patients. The typical advancement at the incisal edge was 2 to 5 mm.

CONCLUSION

This method represents a new approach for nonextraction therapy in the mandible. It requires no soft or hard tissue grafting and results in favorable tissue conditions at the distraction site.

Predetermined implant positioning by means of a novel guide template technique

This paper presents a novel guide template technique for implant placement. In esthetic implant dentistry with its restoration-driven implant placement as well as in complete-arch cases with multiple implants, the precise positioning and angulation of dental implants is crucial for achieving the desired prosthetic results. Difficulties in implant positioning may arise especially with grafted jaws resulting from communication problems between surgeon and prosthodontist. This method may alleviate some of the problems common to conventional template techniques, where the drill is usually directly guided by the template. The key idea is to fixate the implant position and angulation by the help of Kirschner wires which are inserted in the alveolar ridge right through the mucosa before elevation of a mucoperiosteal flap. Thanks to this sequence, the template for guiding the wires may be positioned precisely, even on grafted edentulous ridges. After the insertion of the wires, the bone is exposed and the implant cavities prepared with a trephine drill guided over the wires alone or over wires combined with a special guidance cylinder fitting the trephine drill. The method may be combined with different planning and radiological techniques. Since the use of the template is detached from the actual drilling process, the danger of introducing debris of plastic or metal into the preparation site may be avoided. The present technique might be helpful for difficult cases by improving communication between prosthodontist and surgeon and also render additional security to the surgeon with less routine in dental implant insertion.