Effects of Guided Bone Regeneration Around Commercially Pure Titanium and
Hydroxyapatite-Coated Dental Implants. I. Radiographic Analysis
William C. Stentz, Brian L. Mealey, Pirkka V. Nummikoski, John C.
Gunsolley, and Thomas C. Waldrop
The purpose of this study was to determine which treatment of a large
osseous defect adjacent to an endosseous dental implant would produce the
greatest regeneration of bone and degree of osseointegration: barrier
membrane therapy plus demineralized freeze-dried bone allograft (DFDBA),
membrane therapy alone, or no treatment. The current study assessed
radiographic density changes in bone within the healed peri-implant osseous
defect. In a split-mouth design, 6 implants were placed in edentulous
mandibular ridges of 10 mongrel dogs after preparation of 6 cylindrical
mid-crestal defects, 5 mm in depth and 9.525 mm in diameter. An implant
site was then prepared in the center of each defect to a depth of 5 mm
beyond the apical extent of the defect. One mandibular quadrant received
three commercially pure titanium (Ti) screw implants (3.75 x 10 mm), while
the contralateral side received three hydroxyapatite (HA) coated root-form
implants (3.3 x 10 mm). Consequently, the coronal 5 mm of each implant was
surrounded by a circumferential defect approximately 3 mm wide and 5 mm
deep. The three dental implants in each quadrant received either DFDBA
(canine source) and an expanded polytetrafluoroethylene membrane (ePTFE),
ePTFE membrane alone, or no treatment (control). Standardized radiographs
were taken at 1 week and 4 months post-implant placement. Computer-assisted
densitometric image analysis (CADIA) was performed at 6 areas of interest
(coronal, middle, and apical defect areas mesial and distal to each
implant) for each of the implant sites. Significantly greater increase in
bone density was obtained using DFDBA/ePTFE compared to ePTFE alone or the
controls; likewise, ePTFE alone resulted in greater bone density change
than the controls. There were no significant differences in radiographic
bone density adjacent to Ti versus HA-coated implants. When 3 dogs having
postoperative membrane complications were eliminated from the analysis, the
results were similar with the exception that defects adjacent to Ti
implants had significantly less density gain when compared to HA-coated
implants. The results of this study indicate the use of DFDBA/ePTFE in
large surgically-created defects promotes a denser healing of bone adjacent
to implants when measured radiographically than either ePTFE alone or no
treatment.
J Periodontol 1997;68:199-208.
A Bone Regenerative Approach to Alveolar Ridge Maintenance Following Tooth
Extraction. Report of 10 Cases
V. Lekovic, E.B. Kenney, M. Weinlaender, T. Han, P. Klokkevold, M. Nedic,
and M. Orsini
Ten patients who required two or more anterior teeth extractions were
utilized in this study. Extraction procedures were carried out with a
full-thickness surgical flap approach. After flap reflection, teeth were
removed with a minimum of trauma to the surrounding bone. Following
extraction, silicone-based impression techniques were used to produce a
model of the alveolar process and small metal pins were placed in the
alveolus to be used as fixed points to make measurements of ridge
dimensions. One socket was covered with an expanded polytetrafluoroethylene
(ePTFE) barrier membrane (experimental site); the other socket was a
conventional control. The soft tissue flaps were then mobilized using
periosteal releasing incisions, and the wound closed with ePTFE mattress
sutures. Six months following extraction, patients were treated with flap
surgery to expose both extraction sites to remove the ePTFE membranes and
to measure ridge dimensions using the pins as fixed points. Clinical and
model measurements have shown statistically significant better ridge
dimensions at experimental sites than at control sites (P less than or
equal to 0.05). Three patients with exposed membranes had similar
dimensional changes as controls. Results from this study suggested that
this improved technique offers a predictable alveolar ridge maintenance
enhancing the bone quality for dental implant procedures and esthetic
restorative dentistry.
J Periodontol 1997;68:563-570.
Actisite
A new antibiotic therapy using tetracycline-impregnated fibers(trade name
Actisite) for treating localized periodontal infection has been cleared for
marketing by the U.S. Food and Drug Administration. These fibers offer new
options to help control subgingival microflora and bleeding in isolated
sites of periodontal disease.
This first controlled local-antibiotic-delivery-system is supplied as a
nine-inch monofilament of ethylene/vinyl acetate copolymer 0.5mm in a
diameter containing 12.7mg of evenly-dispensed tetracycline. When placed in
a periodontal pocket, it provides continuous release of tetracycline with a
mean gingival fluid concentrations of 32 micrograms/ml. 250mg of oral
tetracycline generally produces about 10 micrograms/ml in the gingival
sulcus fluid.
Studies have demonstrated that scaling and root planing followed by
tetracycline fiber placement was more effective than scaling alone and
reduced mean pocket depth by an additional 0.6mm and bleeding on probing by
an additional 13% after six months. Bacterial populations were also
reduced. The benefits of the fibers seem to increase over a six-month
period, possibly due to the fact that tetracycline is retained in the roots.
Proctor & Gamble, which is marketing Actisite, recommends tha fibers be
used as an adjunct to therapy for recurrent periodontal disease in isolated
individual problem sites. The fibers can also be used in acute periodontal
abscesses, but should be loosely packed to allow for drainage. If the site
fails to respond to fiber therapy, then periodontal surgery may be indicated.
A single fiber is placed into a completely fill pocket to its base using a
cord packer. Cyanoacrylate adhesive is used to help secure the fiber in
place and the patient is instructed not to brush or floss the area for ten
days. Local analgesia is usually not required at placement and the fibers
are removed after ten days as they become a foreign body after about 14
days. The fibers should be placed by the doctor only. If stripping of the
epithelial attachment occurs and is kept open by the apical placement of
the fiber, a permanent increase in pocket depth may occur.
The development of tetracyline fibers is an important step in treating
localized periodontal infections by sustained high-dosage of local
antibiotic delivery. When multiple areas are infected, tetracycline fibers
are not the treatment of choice. Many other medications are currently being
tested, including metronidazole, doxycycline, minocycline and chlorhexidene
in chips, fibers, strips and gels. The obvious next step would be a
delivery system that is more time efficient at placement, biogrades in the
pocket so removal is not necessary, and is known to be effective against
the specific bacterial infection under treatment.
Clinical studies indicate that some sites don't respond favorably to the
tetracycline fibers. This may be because tetracycline is a non-specific
antibiotic and some specific infections are resistant to tetracycline or
may be located too deep in the tissue to be affected. One tetracycline
fiber study reported that some patients infected with Actinobacillus
actinomycetemcomitnas, which is know to invade tissue, got worse or showed
no improvement.
Tetracycline fibers are the first of an exciting new mode of therapy in our
continuing fight against periodontal disease.
"Updates": In Wilson's recent study pretaining to a five year investigation
of treating periodontal disease with scaling and root planing plus
tetracycline fibers a regression was noted from the original gains in the
previous parent study that lasted six months. It appears that the use of
the tetracycline fibers provided no significant advantage with regards to
probing depth reduction or clinical attachment gain in a five year period.
This underscores the need for long-term evaluations for these types of
therapy.
References:
1. Listgarten M: Effect of Tetracycline and /or scaling on human
periodontal disease. J. Clin Perio 1978 5:246-71.
2. Newman MG, Kornman KS, Doherty FM: A 6-month multi-center evaluation of
adjunctive tetracycline fiber therapy used in conjunction with scaling and
root planing in mainternace patients: J Periodontl 1994 Jul;65(7):685-91.
3. Kerry G: Tetracycline-loaded fibers as adjunctive treatment in
periodontal disease. JADA 1994 Sep;125(9):1199-1203.
4. Tonetti MS, Pini-Prato G, Cortellini P: Principles and clinical
applications of periodontal controoled drug delivery with tetracycline
fibers. Int. J. Periodontics Restorative Dent 1994 Oct;14(5):421-435.
5. Wilson T. Long-Term Results of Tetracycline Therapy. J Perio
1997;68:1029-1032.
